Ocean Heat Storage: Implications for Climate Change Research

[joelupchurch]

This paper "Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435 Hansen et al" pdf available http://pubs.giss.nasa.gov/abstracts/2005/Hansen_etal_1.html" seems to have been very influential in research on climate change.

The basic argument is that very little of the Earth's heat is stored in the atmosphere and that the heat stored in the first 2.5 meters of the ocean is equivalent to the whole atmosphere. Therefore ocean heat storage is a more reliable tool to measure the radiative imbalances in our climate system than surface temperature changes.

I've noticed that even researchers at the far end of climate debate from Hansen are starting to use the ocean heat storage metric in their papers.

Part of this is probably driven by deployment of the Argo float system that has given us unprecedented capacity to measure changes in ocean temperatures down to 2000 meters.
http://www.argo.ucsd.edu/" . There are currently 3325 active Argo floats providing real time information about ocean conditions.

 

[chriscolose]

The recent Levitus et al 2009 paper may be a good read
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf[/URL]

 

[sylas]

This paper "Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435 Hansen et al" pdf available http://pubs.giss.nasa.gov/abstracts/2005/Hansen_etal_1.html" seems to have been very influential in research on climate change.

The basic argument is that very little of the Earth's heat is stored in the atmosphere and that the heat stored in the first 2.5 meters of the ocean is equivalent to the whole atmosphere. Therefore ocean heat storage is a more reliable tool to measure the radiative imbalances in our climate system than surface temperature changes.

I've noticed that even researchers at the far end of climate debate from Hansen are starting to use the ocean heat storage metric in their papers.

Part of this is probably driven by deployment of the Argo float system that has given us unprecedented capacity to measure changes in ocean temperatures down to 2000 meters.
http://www.argo.ucsd.edu/" . There are currently 3325 active Argo floats providing real time information about ocean conditions.

This is really interesting stuff… and with lots of unanswered questions which adds to the interest!

It's long been known that the ocean's heat capacity is important; the problem has always been the computation to take it into account.

The equivalence of heat storage for the atmosphere to about 2.5 meters of ocean is a back of the envelope calculation, using century old physics. Heat capacity of air is about 1000 kJ/kg; and for water is about 4000 kJ/kg. (Single digit accuracy) The atmosphere has a pressure of 1000 hPa, under gravity of 10 m/s^2; hence there is about 10,000 kg of atmosphere for each square meter of Earth's surface. That has the heat capacity of 2,500 kg of water. You get 2,500 kg of water per square meter with a depth of 2.5 m.

Strictly speaking, this isn't a comparison with the whole ocean, but with atmosphere and ocean over a single square meter. To consider the whole Earth, you'd have to note that about 30% of the surface isn't ocean. Taking this into account, the heat capacity of the entire atmosphere is about the same as the heat capacity of the top 3.4m of the world ocean.

That only tells you that the ocean is important, which has long been understood. The modeling of climate and weather has progressed steadily thanks to more detailed measurement of factors involved, better mathematical descriptions of the physics, and faster computers to actually handle the computations. A really helpful background historical summary of the progress in quantified understanding of weather and climate over the last century is at http://www.aip.org/history/climate/GCM.htm, a chapter out of Spencer Weart's online book on the discovery of global warming.

The paper you have cited by Hansen et. al. has been influential, not so much for persuading people to consider the ocean, but for a quantified estimate of it's impact in terms of the net energy flow currently going into the ocean.

However, in my opinion the estimate given there is a substantial over estimate. They quote 0.85 W/m^2 +/- 0.15 net imbalance for the whole planet. But if you read the paper, it's clear this number is not a measurement, but based on the models. The actual measurements do indicate a positive imbalance, but substantially less. Climate models have been an enormous help in this whole field, but modeling of ocean circulation still has a ways to go before I'd put too much weight on this specific number.

The research Chris has cited is a better guide, I think. The Argo floats you mention are a key part of this – although much of the issue there is sorting out teething problems with systematic measurement errors.

Bottom line: the Leviticus et al paper estimate increasing heat content of the world ocean at roughly 4e21 J/year over recent decades, and this fits broadly with a range of empirical estimates.

Crunch the numbers: a year is 3.15e7 seconds, and the Earth's surface is 5.1e14 m^2, and this works out to about 0.25 W/m^2 as the energy imbalance.

I think this is a much more plausible value than the 0.85 used in Hansen et al (2005).

Cheers -- sylas

 

[joelupchurch]

The recent Levitus et al 2009 paper may be a good read
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf[/URL][/QUOTE]

I'm not comfortable with how they mix in the lower quality pre argo data. There seems to be a sharp change in the trendline around 2004. Is that real or just because they are mixing apples and oranges?

 

[sylas]

I'm not comfortable with how they mix in the lower quality pre argo data. There seems to be a sharp change in the trendline around 2004. Is that real or just because they are mixing apples and oranges?

I'm not sure what you refer to. I've got the paper; you can refer to a figure or a page. I've not read it in great detail. I know some of the issues involved in this, but only from comparatively superficial reading of the associated literature. I'm not an expert.

One of the problems has been systematic errors in Argo measurements. Most of that is probably ironed out, but it's an ongoing issue to sort out problems with Argo. In fact, I see that just yesterday there was a recall notice put out at the http://www.argo.ucsd.edu/seabird_notice.html wanting to stop float deployment and bring in floats for repair to pressure sensors. Pressure sensors seem to have been something of a problem all along.

This is a great experiment, but they are still sorting it all out as far as I can see. It's got great potential to help sort out ocean measurement.

A part of this paper (Levitus et al 2009) has been to consider the impact of corrected Argo data from earlier systematic errors. They also seem to be working on identifying systematic errors in older "bathythermograph" measurements that I don't know about, but which are a crucial part of the longer instrument record.

Argo is still new, so it can't tell you much about long term trend by itself. There certainly is real short term variation; there is also short term sampling errors. When you are dealing with incomplete data the short term variation is often hard to pin down. Furthermore, it's really the long term trend people are most interested in, at this point.

As a general rule in ANY measurement of a trend of anything, you can't draw conclusions from a short sample. So sure, there is likely to be some real changes from year to year. The idea of a trend is to get a longer term picture that is not distorted by short term natural oscillations and variations.

The other important recent reference is:

• Domingues, C.D., (2008) Improved estimates of upper-ocean warming and multi-decadal sea-level rise, in Nature Vol 453, pp 1090-1093 (19 June 2008) doi:10.1038/nature07080

That is an analysis of the instrument record up to 2003, but it is by the Argo floats research group and does use this new source of information. They obtain a trend in ocean heat content involving 16 +/- 3 *10²² J from 1961 to 2003; and that corresponds to a planetary energy imbalance of 0.24 W/m² – very similar indeed to Levitus et al (2009).

Cheers -- sylas

 

[joelupchurch]

I'm not sure what you refer to. I've got the paper; you can refer to a figure or a page. I've not read it in great detail. I know some of the issues involved in this, but only from comparatively superficial reading of the associated literature. I'm not an expert.

I'm referring to figure 1 on page 2. From 2000 to 2004 it increases from 7x10²² to 13x10²² joules and it then flattens out.

I just did a back of the envelope calculation based on the ocean storing 1.5x10²² joules a year. I figure that the human race uses about 5x10²⁰ joules per year, so the ocean was storing 30 times as much energy as the human race was consuming.

http://tonto.eia.doe.gov/ask/generalenergy_faqs.asp" . There are 1055 joules in a BTU.

 

[Xnn]

— The global mean concentration of CO2 in 2005 was 379
ppm, leading to an RF of +1.66 [±0.17] W m–2.

The combined anthropogenic RF is estimated to be +1.6
[–1.0, +0.8] W m–2, indicating that, since 1750, it is extremely
likely that humans have exerted a substantial warming
influence on climate.

Increasing concentrations of the long-lived greenhouse
gases (carbon dioxide (CO2), methane (CH4), nitrous oxide
(N2O), halocarbons and sulphur hexafl uoride (SF6); hereinafter
LLGHGs) have led to a combined RF of +2.63 [±0.26] W m–2.

From page 131. RF = Radiative Forcing

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf

 

[joelupchurch]

The other important recent reference is:

• Domingues, C.D., (2008) Improved estimates of upper-ocean warming and multi-decadal sea-level rise, in Nature Vol 453, pp 1090-1093 (19 June 2008) doi:10.1038/nature07080

That is an analysis of the instrument record up to 2003, but it is by the Argo floats research group and does use this new source of information. They obtain a trend in ocean heat content involving 16 +/- 3 *10²² J from 1961 to 2003; and that corresponds to a planetary energy imbalance of 0.24 W/m² – very similar indeed to Levitus et al (2009).
[/QUOTE]

I found a free copy of the paper here http://www.astepback.com/GEP/Nature%20Higher%20Warming%20SLR%20rates.pdf".

I'm not sure how much to read into their agreement with Levitus. It looks like they are working from the same datasets and may be using the same corrections.

I don't know why they used the pre 1970 data. The 1 standard deviation band is so wide, that they might as well insert random numbers. I'm also a little concerned that they cut off their graph at 2003 when Leviticus includes data through 2008.

 

[joelupchurch]

The other important recent reference is:

• Domingues, C.D., (2008) Improved estimates of upper-ocean warming and multi-decadal sea-level rise, in Nature Vol 453, pp 1090-1093 (19 June 2008) doi:10.1038/nature07080

That is an analysis of the instrument record up to 2003, but it is by the Argo floats research group and does use this new source of information. They obtain a trend in ocean heat content involving 16 +/- 3 *10²² J from 1961 to 2003; and that corresponds to a planetary energy imbalance of 0.24 W/m² – very similar indeed to Levitus et al (2009).

Sorry I messed up. The part above was from a post by sylas not me.

 

[sylas]

I'm referring to figure 1 on page 2. From 2000 to 2004 it increases from 7x10²² to 13x10²² joules and it then flattens out.

OK. I see what you mean. Here's the same data as presented at the NOAA page for this research: Global Ocean Heat Content:

The data being plotted here and in figure 1 of Levitus et al (2009) is in the "World Ocean" column of the file: ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/DATA_ANALYSIS/3M_HEAT_CONTENT/DATA/basin/3month/h22-w0-700m1-3.dat[/URL] (ftp, NOAA site). The rise you mean is from the data point for 2001 (5.073e22 J) to 2004 (12.154e22 J). You can also get at slightly more detailed 3-monthly data from the same pages.

This rise around 2003 is a part of the Argo data; it is not something that comes from trying to merge older data with new "better" data. I don't think you can draw any definite conclusions about a short term effect like this; it could be almost anything, from a calibration error to a real heat content jump to a measurement artifact of how floats are distributed with changing currents. The overall picture of increasing heat content, however, is pretty unambiguous. There are various short term oscillations in ocean currents and temperature distributions, like the ENSO oscillations with El Nino and La Nina. That's a real effect – not simply as a change in total heat content, but signal that can confound short term measures of heat content.

In this data the whole trend is a strong positive, and there's shorter noise and up and down all along the timeseries. In the Domingues et al paper (2008) that I cited, you can see their figure 1 also showing a similar up surge. Since it is the same data being analysed, this isn't enough to tell how much is an artifact of measurement, and how much is a real difference in shift. The data files allow you to look at North and South Hemisphere separately, and at a 3-month series rather than annual data, and it looks a bit like there was at least some role for a fortuitous case of simultaneous upswings in both NH and SH throughout the year 2003 and a bit each side… but either NH or SH in isolation looks more like ongoing noisy variation and an increasing trend.


[QUOTE]I just did a back of the envelope calculation based on the ocean storing 1.5x10[SUP]22[/SUP] joules a year. I figure that the human race uses about 5x10[SUP]20[/SUP] joules per year, so the ocean was storing 30 times as much energy as the human race was consuming.

[PLAIN]http://tonto.eia.doe.gov/ask/generalenergy_faqs.asp" . There are 1055 joules in a BTU.[/QUOTE]

That sounds about right. The contribution of human activity by direct energy production is just about negligible. As far as the Earth is concerned, the only source of energy that matters is the Sun. That's why the greenhouse effect is so important. This isn't a source of energy – our actual energy input is tiny by comparison. The greenhouse effect has such a big impact because it alters how the Earth responds to the solar energy input.

Cheers -- sylas

 

[sylas]

I'm not sure how much to read into their agreement with Levitus. It looks like they are working from the same datasets and may be using the same corrections.

Of course. The thing is that this IS Argo data being used.

I don't know why they used the pre 1970 data. The 1 standard deviation band is so wide, that they might as well insert random numbers. I'm also a little concerned that they cut off their graph at 2003 when Leviticus includes data through 2008.

It takes a lot of time and work to do these analyses. You can't just read off a value from Argo data. A global heat content figure is obtained by a lot of analysis of thousands of individual floats, along with all the issues of calibration and instrument drift and known errors with pressure sensors. Hence a paper submitted in 2007 is using data from some time prior to that.

There's a slightly different focus in the two papers Levitus (2009) is particularly concerned with correcting errors in XBTs, whereas Domingues (2008) is particularly concerned with fixing problems with recently discovered problems with the Argo floats. The Levitus paper is a repeat of an older analysis, and has been updated to take into account the new Argo corrections amongst other things; and I guess they rely upon the Argo team for the corrections to systematic Argo errors. It appears so from the acknowledgments of the papers.

I don't know how you conclude pre 1970 data is that bad. It certainly does not appear so to my analysis. The natural variation in measurement is very similar all along the series. You do have less trend prior to 1970, which is unsurprising. All the related data, on sea surface measures and sea level and so on, all indicate that the ocean has been warming substantially more since 1970 or so than prior. That's pretty definite.

We'd like to know how much... and so pre-1970 data is of considerable interest. But the figure does not show any greater "randomness" before 1970 than after, and it fits well with other related data, like the SST record. I also ran a quick check of my own using confidence bounds based on the data only and a simple regression analysis. There's a little bit of extra amplitude to the short term variations through the 1980s, but only very minor and probably not significant. There's no indication at all of additional randomness prior to 1970.

Cheers -- sylas

 

[joelupchurch]

Of course. The thing is that this IS Argo data being used.
I don't know how you conclude pre 1970 data is that bad. It certainly does not appear so to my analysis. The natural variation in measurement is very similar all along the series. You do have less trend prior to 1970, which is unsurprising. All the related data, on sea surface measures and sea level and so on, all indicate that the ocean has been warming substantially more since 1970 or so than prior. That's pretty definite.

Cheers -- sylas

Ignore the data points in figure 1 and look at the gray band marking the 1 std dev. If they are using it the way I'm familiar with, then the line is the measured value and the band represents where the is a 75% chance that actual value is. The pre 1970 data band is almost 3 times wider than the post 1970. You can fit any trend you want inside that band.

This assumes the data actually following a Gaussian distribution.

 

[sylas]

Ignore the data points in figure 1 and look at the gray band marking the 1 std dev. If they are using it the way I'm familiar with, then the line is the measured value and the band represents where the is a 75% chance that actual value is. The pre 1970 data band is almost 3 times wider than the post 1970. You can fit any trend you want inside that band.

This assumes the data actually following a Gaussian distribution.

Ah! My apologies… I was still looking at figure 1 in Levitus et al (2009). In the Levitus analysis the error bars are not actually plotted, but they can be found at the download site.

We need to bear in mind that everything in these figures is a calculation; including the error bars. There is no such thing as a direct measurement of the ocean's total heat content – it has to be inferred on the basis of many thousands of measurements and a whole heap of analysis. Both Levitus (2009) and Domingues (2008) are papers that are clearing up systematic errors in earlier measurements.

Here is a copy of Figure 1 from Domingues (2008):

(image source: realclimate blog).
What this shows are two older calculations and the new revision that Domingues et. al. have obtained, in black. The error bars shown here represent the one standard deviation of the Domingues et. al. analysis, and this does indicate that the analysis used is degraded for trends prior to 1970.

One of the lines there in the Domingues paper, given in red, is from Levitus (2005).

The first paper we’ve been using in this thread is Levitus (2009), introduced by Chris Colose. This is mainly concerned with cleaning up errors in the XBT datasets, and updating their previous and erroneous 2005 analysis. The figure 1 in Levitus (2009) does not include the error bars, but it does give a side-by-side comparison with their 2005 analysis, as shown in red in Domingues (2008). There are error bars in the datasets that I linked to previously. Hence I can plot them for you. This plot shows the annual OHC for the Levitus (2009) analysis, along with hi and lo limits corresponding to one standard error. The baseline is a bit different to the published figure… this is simply a somewhat arbitrary choice for a reference zero point.

I've also plotted here the width of the standard error calculation independently above the main data plot, which gives a better idea of how the standard error develops over time.

There are different error bars here in Levitus (2009) because they are different datasets and different calculations. Levitus is working mainly with XBT data. This is reasonably seen as a reduction in errors associated with the older dataset; but it is also likely that the error bars represent something a bit different in this case… the method error without explicit additional measurement error. That's fair enough in a downloaded dataset; it's probably method error that's more useful for other analysis. However, it remains the case that the two analyses by Levitus and Domingues are different analyses with their own associated error estimates. The 2009 analysis from Levitus et al is mostly somewhere in between their 2005 analysis and the Domingues analysis.

I don't have direct access to the Domingues et al data -- it is available, but not as a direct download, and I haven't put in an order for it by email. But it looks like the big hump from the Levitus 2005 analysis is mostly gone in 2009. What's left of that hump still represents a difference between the two analyses.

The Domingues 2008 error bars most probably include a larger measurement error component, not explicitly addressed in Levitus 2009. That's how I read it, in any case.

A great summary of this ongoing work is available at the NASA Earth observatory: Correcting Ocean Cooling. It tells the story of how the errors in the Argo floats were found and fixed, and gives a good insight into how difficult it all is. Although the article focuses on the Argo team, the final word of the article goes to Syd Levitus:

"Models are not perfect," says Syd Levitus. "Data are not perfect. Theory isn't perfect. We shouldn't expect them to be. It's the combination of models, data, and theory that lead to improvements in our science, in our understanding of phenomena."​

Cheers -- sylas

 

[Saul]

It appears the oceans have stopped warming. I am not sure that is cause for celebration.


http://www.ingentaconnect.com/content/mscp/ene/2009/00000020/F0020001/art00008;jsessionid=1k9alnlpdhr7c.alice

Ocean heat content data from 2003 to 2008 (4.5 years) were evaluated for trend. A trend plus periodic (annual cycle) model fit with R2 = 0.85. The linear component of the model showed a trend of −0.35 (±0.2) × 1022 Joules per year. The result is consistent with other data showing a lack of warming over the past few years.

Author: Loehle, Craig

Source: Energy & Environment, Volume 20, Numbers 1-2, January 2009 , pp. 101-104(4)

Cooling of the global ocean since 2003

http://www.npr.org/templates/story/story.php?storyId=88520025

 

[joelupchurch]

It appears the oceans have stopped warming. I am not sure that is cause for celebration.


http://www.ingentaconnect.com/content/mscp/ene/2009/00000020/F0020001/art00008;jsessionid=1k9alnlpdhr7c.alice



Author: Loehle, Craig

Source: Energy & Environment, Volume 20, Numbers 1-2, January 2009 , pp. 101-104(4)

Cooling of the global ocean since 2003

http://www.npr.org/templates/story/story.php?storyId=88520025

I found a copy of the paper here:

http://www.ncasi.org/publications/Detail.aspx?id=3152"

As far as I can tell, there is no data in the paper that isn't in the Leviticus paper we have been discussing. Frankly, I think, my earlier characterization of the data as essentially flat is more accurate. The trend they refer to overwhelmed by seasonal variations.

I didn't think that was remarkable, since it was consistent with the surface temperature record with some lag.

 

[Saul]

I found a copy of the paper here:

http://www.ncasi.org/publications/Detail.aspx?id=3152"

As far as I can tell, there is no data in the paper that isn't in the Leviticus paper we have been discussing. Frankly, I think, my earlier characterization of the data as essentially flat is more accurate. The trend they refer to overwhelmed by seasonal variations.

I didn't think that was remarkable, since it was consistent with the surface temperature record with some lag.

A trend of minus -0.35 x 10^22 Joules/year for the period 2003 to 2008 is not essentially flat. A negative trend in the planet’s ocean temperature shows the planet is cooling. A clearer description than "a lack of warming of over the last few years" is the planet was been cooling from the period 2003 to present.

Ocean heat content data from 2003 to 2008 (4.5 years) were evaluated for trend. A trend plus periodic (annual cycle) model fit with R2 = 0.85. The linear component of the model showed a trend of -0.35 (±0.2) x 10^22 Joules per year. The result is consistent with other data showing a lack of warming over the past few years.

Both the atmosphere and the ocean appear to be cooling. (Which makes sense as sea ice is also increasing.)

What is causing a significant five year cooling of the planet?

Comment:
The upper stratospheric temperature paper that was published in 2008 only used data up until 2003.

 

[sylas]

Careful guys; this is descending into crackpottery and irrelevance. There's a reason the Earth Science forum requires peer-reviewed references for support of controvertial claims – there's a lot of flagrant nonsense out there.

This thread is about the topic of Ocean Heat content. This is an excellent topic, and there are some genuine scientific puzzles and open questions here. Unfortunately, the thread risks being derailed into consideration of low grade popular caricatures of genuine science investigation.

Specifically.

• Loehle 2009 is not a legitimate peer-reviewed science paper. The available data is much better examined using the legitimate scientific papers already cited rather than distracting into fringe oddities.
• Bizarre claims are being made with no reference. The claim that "sea ice is increasing", for example, is symptomatic of the extreme flight from reality that shows up so often in these debates.
• Irrelevant distractions are showing up. For example, we have large and badly produced graphs of tropospheric temperature. That's not the ocean. (Not to mention that the data actually shows more warming than in the ocean. More below.)
• There is no "significant five year cooling". Five years is a short variation, almost by definition a five year "trend" is not significant!

More detail on each point.

References from Energy and Environment

Energy and Environment is not a science journal. It was set up by an English climate skeptic with no profession background in the topic. It doesn't show up in the recognized ranking systems and impact factors for scientific publications, anymore than OMNI or Readers Digest. The founder and main editor is Sonja Boehmer-Christiansen, an academic with background in geography, politics and policy – not science at all. The magazine has become a clearing house for easy publication of low grade material that can't get into a real science journal. Indeed, that was the aim. Boehmer-Christiansen apparently thinks there a bias against publishing work running counter to the mainstream science; but she's got it backwards. The mainstream is what it is because it has a bias against shoddy methodology and pseudoscience.

This "journal" has a lot of currency OUTSIDE science, where it is eagerly lapped up by people who don't accept the basic findings of conventional climatologists. It's cited in blogs, pundits, congressional submissions, etc, etc… but it has very little circulation in university libraries.

The paper by Craig Loehle (2009) would be okay as an undergraduate project, but the low level engaged is very obvious if you look at it side by side with a real science paper, such as Levitus (2009) or Domingues (2008) that has been used in the thread. Loehle's actual conclusions are rather weaker than his abstract suggests. The conclusion of the article is as follows:

While the current study takes advantage of a globally consistent data source, a 4.5-year period of ocean cooling is not unexpected in terms of natural fluctuations. The problem of instrumental drift and bias is quite complicated, however, (Domingues et al. 2008; Gouretski and Koltermann 2007; Wijffels et al. 2008; Willis et al. 2004, 2008a) and it remains possible that the result of the present analysis is an artifact.​

Exactly so. The result is "not unexpected" in terms of natural fluctuations, and even worse – it remains possible that the result is an "artifact".

The analysis in the paper is trite. It's nothing but an exercise in curve fitting, using a distinctly odd method for finding a trend. He fits a sine curve to the data as a way of handling the annual cycles, and then fits for an underlying linear slope, and also a linear change in amplitude. That pretty much ensures he's going to get results with limited meaning. It makes sense to have a linear trend over a long period of time, but a linear damping?!? Seriously, forget the Loehle paper. It's not going to be a part of the actual ongoing scientific work, and with good reason. Stick with the science journals. It's all the same data being used, and the science journals do it much better.

Tropospheric temperature.

We've got two huge graphs above, badly produced, talking about atmospheric trends.

This brings up a whole new topic. Fundamentally, the atmosphere shows MUCH more variation than the surface or the ocean, which puts bigger uncertainty on the trends. But in fact, the graphs Saul have provided do show an overall warming trend, along with a lot of up and down that is larger than at the surface.

The regression trend for his RSS data is 0.155 C/decade warming, with 95% confidence bounds of 0.135 to 0.175. The trend in the UAH data is 0.128 C/decade, with 95% confidence bounds of 0.107 to 0.149. There's a pretty good working relationship between the RSS and UAH research groups. The scientific disagreements are the name of the game. Each group continues to work with the other in helping to find problems. The RSS website has a really nice little tool that allows you to compare all the various datasets involved. See http://www.ssmi.com/msu/msu_data_validation.html. But take care to read the associated text; you get different trends when data is weighted by sampling to fit radiosonde data, probably because of the increased warming over the land.

For what it is worth, the sea surface temperature trend over this same period is about 0.133 C/decade, with 95% confidence limits of about 0.121 to 0.144, using the standard HadSST2 dataset: here. The deeper ocean warms more slowly than this.

This thread is about Ocean heat content.

The measurement of tropospheric temperature is an ongoing active research question. As matters stand, this is mostly about measurements. There are some theoretical issues here about refining dynamic models of the atmosphere generally, but as matters stand the models are consistent with the wide range of plausible measurement. Furthermore, this all stands distinct from questions of what is causing the rising temperatures we observe. The primary modeling issues here would be the same whether warming was driven by greenhouse, or insolation, or albedo. Theoretical predictions are within the range of the available measurements, and ongoing work to resolve discrepancies between different data sets makes for lots of interesting and contrasting work in the scientific literature. But it's almost all about trying to nail down difficult measurements.

The recent 5 year trend

Anyone who talks about a five year climate trend doesn't understand trends.

Over five years, the natural variation of climate and weather means you are necessarily looking at local variation. This is not a measure of "trend" at all, but of small scale local change. This is certainly interesting in its own right, but it isn't trend. A trend is something that extends over the time, and for climate and weather, the five year scale is dominated by natural oscillations. The long term trends show up only over longer periods.

Nor is it particularly surprising that a number of climate indices show lower values recently. The major contributing factor for this is the ENSO oscillations -- El Nino, La Nina -- which have just been through a cool point after a high point about five years ago or so. A good discussion of this is

• Fawcell, R (2007) http://www.amos.org.au/documents/item/82 , Bulletin of the Australian Meteorological and Oceanographic Society, Vol. 20, pp. 141-148.

Sea ice

The sea ice trends are strongly downwards in the Arctic, and about level in the Antarctic. Saul says:

Both the atmosphere and the ocean appear to be cooling. (Which makes sense as sea ice is also increasing.)

The above statements just don't make any sense. The actual trend for ocean and for atmosphere shows warming. Saul has mixed up a short term swing with a trend. That's just wrong, and fails to understand what "trend" means in the context of data with natural up and down variation. The oscillations are not trend, and the whole idea of trend is to abstract away from the short term variations. Trend is, by definition, not something you can find within spans of time dominated by oscillations.

But the sea ice thing takes wrong to a whole new level.

The sea ice talking point is symptomatic of the low level to which popular debate has sunk. What we actually have with sea ice is no significant trend in the Antarctic, and a very strong and unambiguous drop in the Arctic. You get the same thing with any actual scientific source of data, this is not ambiguous at all. There are good diagnostic timeseries for HadISST at the Hadley Centre.

Recently, however, Washington Post columnist George Will produced an incredible piece of nonsense mentioning increasing sea ice. The fallout from this was interesting and IMO symptomatic of the low grade of popular debate. The Washington Post has since published a couple of much more sensible op-eds on this, specifically noting that George Will's conclusions contradict the actual scientific data. Some readers might think that this represents two sides of a scientific debate. It doesn't. It represents error and denial on one side and science on the other.

Cheers -- sylas

 

[Saul]

Careful guys; this is descending into crackpottery and irrelevance. There's a reason the Earth Science forum requires peer-reviewed references for support of controvertial claims – there's a lot of flagrant nonsense out there.

Cheers -- sylas

Sylas,

Name calling of the author, the publisher, and of others in the forum does not prove your point.

Data indicates the planet (both hemispheres) was been cooling for the last 5 years. Ignoring the data does not change the data.

I provided a paper that shows the planet's oceans (Total heat content.) have been cooling for the last 5 years.

http://www.ingentaconnect.com/content/mscp/ene/2009/00000020/F0020001/art00008;jsessionid=1k9alnlpdhr7c.alice

Ocean heat content data from 2003 to 2008 (4.5 years) were evaluated for trend. A trend plus periodic (annual cycle) model fit with R2 = 0.85. The linear component of the model showed a trend of −0.35 (±0.2) × 10^22 Joules per year. The result is consistent with other data showing a lack of warming over the past few years.

http://www.npr.org/templates/story/story.php?storyId=88520025

It is quite reasonable if the continents cool the oceans will also cool. Or alternatively if the oceans are cooling there will be an increase in sea ice and colder temperatures on land.

 

[Saul]

This seems to support the assertion the planet is cooling. i.e. A lack of warming.

http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.jpg

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg

 

[Skyhunter]

Sylas,

Name calling of the author, the publisher, and of others in the forum does not prove your point.

Data indicates the planet (both hemispheres) was been cooling for the last 5 years. Ignoring the data does not change the data.

I provided a paper that shows the planet's oceans (Total heat content.) have been cooling for the last 5 years.

http://www.ingentaconnect.com/content/mscp/ene/2009/00000020/F0020001/art00008;jsessionid=1k9alnlpdhr7c.alice

Energy & Environment is not an acceptable peer reviewed journal on this forum.

This is the communique I received from Monique.

Can you provide me with a link where it says that an article submitted to the journal undergoes peer-review? I can not find it. The journal is also not listed in the ISI's Journal Citation Reports indexing service.

Monique

You are drawing a conclusion that is not supported by the NPR article.

http://www.npr.org/templates/story/story.php?storyId=88520025

It is quite reasonable if the continents cool the oceans will also cool. Or alternatively if the oceans are cooling there will be an increase in sea ice and colder temperatures on land.

That article states that the surface is not cooling.

This is puzzling in part because here on the surface of the Earth, the years since 2003 have been some of the hottest on record.

And ice is melting not growing. (With exceptions; Antarctic sea ice and high altitude glaciers experiencing increased precipitation patterns etc.)

Willis says some of this water is apparently coming from a recent increase in the melting rate of glaciers in Greenland and Antarctica.

"But in fact there's a little bit of a mystery. We can't account for all of the sea level increase we've seen over the last three or four years," he says.

It would think that when the surface temperatures of the oceans oscillate from warm to cold, that warmer water displaces the cooler water that wells up from the bottom. I suspect that with PDO and ENSO being predominately negative, that some of the sea level rise is deep warming that is not being measured.

 

[Saul]

It is asserted the planet's oceans have cooled 2003-2008.

Ocean surface temperatures support that assertion.

http://data.giss.nasa.gov/gistemp/2008/Fig2b.gif

http://data.giss.nasa.gov/gistemp/2008/Fig2b.gif

 

[sylas]

Responding to two posts in one.

Name calling of the author, the publisher, and of others in the forum does not prove your point.

There was no name calling.

Looking over my article, I am satisfied it was entirely fair. The critical remarks were properly focused on ideas and writings, without name calling applied to persons. I stand by them without hesitation, and will repeat them as appropriate. I am not attacking you personally when I refute your claims. Some of what you say is absurd and completely counter factual, well beyond legitimate scientific disagreement. I back up all such assertions. There's nothing personal intended with it; don't take this as animosity.

When I want to make points of my own, I will use positive argument and direct reference to relevant sources from the mainstream of scientific literature and research. My previous post was cautioning against going off topic, and using unreliable material.

I don't even need to make any case on what is and is not reliable as a reference. We already have guidelines here, which require you to use the peer-reviewed scientific literature. If you can't defend a particular hypothesis by showing that it is being argued within the mainstream of science this ought to be a red flag to you, frankly. In any case, that's the rules of the game.

Data indicates the planet (both hemispheres) was been cooling for the last 5 years. Ignoring the data does not change the data.

There is a fall in many climate indices over the last five years, and I have not ignored that at all. I have discussed it explicitly, just above and also in other threads. Short term temperature falls are a consequence largely of the ENSO oscillation, and I backed this up from the mainstream literature. In any case, it is an entirely unexceptional instance of natural variation similar to other rises and falls all along the last 40 years.

The paper I cited for you above, Fawcett (2008) describes the measurement and impact of the southern oscillation (ENSO). There's a lot of work going into understanding and modeling this important source of interannual change. That it exists, and has a strong influence on short term trend, is basic data.

The data shows a definite warming trend on scales where trend is meaningful, and it shows lots of short term variation above and below the underlying trend. A five year span is much too short to show "trend", but the variation is there and actively investigated in the literature. The last five years shows nothing exceptional by comparison with the previous thirty. Short term variations like this are actively studied in the literature.

It is quite reasonable if the continents cool the oceans will also cool. Or alternatively if the oceans are cooling there will be an increase in sea ice and colder temperatures on land.

This sidetrack into sea ice is just silly. The diagrams you linked show precisely what I mentioned before – a strong trend of decreasing ice cover in the Arctic, and no significant trend in the Antarctic. That you see increasing ice cover is surreal. You must be looking at "winter" in isolation, I think. There is an increase in sea ice in winter.

The data shows a strong and unambiguous down trend in sea ice cover, in the Arctic. The Arctic also shows an exceptionally high rate of warming, including the last five years. There is natural variation, just like anywhere else, and individual years can be either up or down, but the Arctic warming is several times stronger than at lower latitudes, and the five year trend is upwards as well.

Note that the extent of ice cover is not defined only by temperature. For example, the immediate cause of exceptionally low levels of ice in the summer of 2007 is wind pushing back the boundary. This made 2007 an outlier, with a minimum in sea ice well below the main trend of reducing cover. 2008 bounced back a bit – though it was still the second smallest summer ice extent on record. Actual scientists measure temperature. They don't make clueless inferences from sea ice cover in isolation of any thought for effects of precipitation, wind and currents. Ref: NASA press release: NASA Examines Arctic Sea Ice Changes Leading to Record Low in 2007.

Sea ice cover says very little about total ocean heat content. There's a small contribution, but ocean heat content is overwhelming driven by the the major oceans where sea ice is not a factor. There are genuine and unresolved open questions about heat content of the ocean. Stay tuned. Josh Willis -- one of the main Argo researchers -- will have some new papers coming out pretty soon, that will be much more relevant.

And the next post:

It is asserted the planet's oceans have cooled 2003-2008.

Ocean surface temperatures support that assertion.

You should read the text, as well as look at the diagram. The diagram you've reproduced shows both the longer warming trend, and the shorter up and down variations, with a fall in temperature in recent years.

You are using the http://data.giss.nasa.gov/gistemp/2008/ , from the Goddard Institute for Space Studies, which is one of the leading research groups on world climate modeling and monitoring. Co-incidentally I was in the middle of preparing a reply using this very summation when you posted the diagram.

The summation starts out by noting that 2008 was the coldest year since 2000, and also one of the 10 hottest years on record -- ALL of which have occurred since 1997. That's a quick insight right there into the nature of both the long term trend and the short term variation. The conclusion of the summation repeats what I have been explained to you here as well.

Summary: The Southern Oscillation and increasing GHGs continue to be, respectively, the dominant factors affecting interannual and decadal temperature change. Solar irradiance has a non-negligible effect on global temperature [see, e.g., ref. 7, which empirically estimates a somewhat larger solar cycle effect than that estimated by others who have teased a solar effect out of data with different methods]. Given our expectation of the next El Niño beginning in 2009 or 2010, it still seems likely that a new global temperature record will be set within the next 1-2 years, despite the moderate negative effect of the reduced solar irradiance.​

That "southern oscillation" is ENSO -- precisely what I also identified as the major cause for a short term drop in temperature. Here's the recent timeseries for the index:

If you compare this plot with your extracted plot of temperatures, the similar features are striking.

Cheers -- sylas

 

[Saul]

Responding to two posts in one.

There was no name calling.

Looking over my article, I am satisfied it was entirely fair. The critical remarks were properly focused on ideas and writings, without name calling applied to persons. I stand by them without hesitation, and will repeat them as appropriate. I am not attacking you personally when I refute your claims. Some of what you say is absurd and completely counter factual, well beyond legitimate scientific disagreement. I back up all such assertions. There's nothing personal intended with it; don't take this as animosity.

Cheers -- sylas

The Southern Sea ice anomaly is the highest in the 45 year period shown. The anomaly is high in both spring and in winter.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg

The Argo ocean temperature data 2003 to 2008 shows cooling if the data is not adjusted.

The paper you quote shows flat ocean temperatures 1957 to 1990 and then a large increase which again flattens 2003 to 2008.

You provide no explanation as to why there is a sudden hockey stick warming for the period 1990 to 2003. Why was there no warming prior to 1990? Why has the warming suddenly stopped?

ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf[/URL]

The global sea surface temperature shows cooling 2003 to present which supports the cooling interpretation of the Argo’s data.

I standby the assertion: the planet is cooling, the cooling trend will accelerate.

New data will either prove or disprove that assertion.

 

[Skyhunter]

The Southern Sea ice anomaly is the highest in the 45 year period shown. The anomaly is high in both spring and in winter.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.south.jpg

The Argo ocean temperature data 2003 to 2008 shows cooling if the data is not adjusted.

What do you mean, "if the data is not adjusted"?

The paper you quote shows flat ocean temperatures 1957 to 1990 and then a large increase which again flattens 2003 to 2008.

It actually shows a positive trend from 1955-1990, followed by a steep warming trend from 1990-2000, and then a very large spike from 2001-2004, and then a leveling off.

You provide no explanation as to why there is a sudden hockey stick warming for the period 1990 to 2003. Why was there no warming prior to 1990? Why has the warming suddenly stopped?

ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/grlheat08.pdf[/URL]
[/quote]
How are these questions relevant to his argument?

I would suggest you take them one at a time and not imply that because they are not specifically addressed that it is indicative of a faulty argument.
[quote]
The global sea surface temperature shows cooling 2003 to present which supports the cooling interpretation of the Argo’s data.
[/quote]
The SST data shows only 2 years of cooling not 5.
[QUOTE]2003 0.4792
2004 0.4642
2005 0.4722
2006 0.4537
[b]2007 0.3784
2008 0.3714[/b]
[PLAIN]"ftp://ftp.ncdc.noaa.gov/pub/data/anomalies/annual.ocean.90S.90N.df_1901-2000mean.dat"[/URL][/QUOTE]
[quote]
I standby the assertion: the planet is cooling, the cooling trend will accelerate.
[/quote]
Maybe this will help.
[URL]http://www.agu.org/pubs/crossref/2009/2009GL037810.shtml"[/URL]
[quote]
New data will either prove or disprove that assertion.[/QUOTE]
Current data does not support that assertion.

 

[Saul]

What do you mean, "if the data is not adjusted"?


http://www.agu.org/pubs/crossref/2009/2009GL037810.shtml"

Current data does not support that assertion.

Skyhunter.

The ocean surface temperatures are colder each year after 2003. i.e. 2003 is the warmest year in the period. That is the definition of cooling. If the ocean surface is warming the temperature increases.

What is your definition of warming?


2003 0.4792
2004 0.4642
2005 0.4722
2006 0.4537
2007 0.3784
2008 0.3714

2008 is the coldest year of the 21st century.

http://data.giss.nasa.gov/gistemp/2008/Fig2b.gif

 

[Skyhunter]

I think you are hyper focused on a very short term variation. There is a lot of water beneath the surface. That is why the ARGO measurements are such an improvement as a measure of overall ocean heat content since the diving robots measure a larger vertical column of water, where as the older buoys and ships just measured the top meter or so.

When surface temperatures are lower in the ENSO regions it is because cooler water is welling up from the bottom bringing with it rich nutrients. We know this is the case because fisherman and now biologists have been observing the link for centuries.

The cool water is displacing the warmer water. Water that was stratified during an El Nino event because the pump is turned off. That displaced warmer water is not radiating it's heat into space, therefore that heat is being stored in the ocean. Other parts of the ocean also oscillate at different cycles and perhaps for different reasons. The point I am making here is that it is very difficult to measure the oceans temperature. What is the temperature change in the deep southern ocean?

The ocean temperature measurements are just one data point. Those measurements are weighed against sea level rise minus glacial mass loss for an estimate of thermal expansion.

The long term trend is still quite positive even while solar activity is low and many major ocean oscillations are neutral to negative. The next El Nino will likely see record temperatures and then you will have the data point that you need.

 

[Xnn]

You're correct Skyhunter;

When cool water from the depths of the ocean wells up to the surface (as during La Nina conditions) then the ocean as a whole is warming more than they would be otherwise. The cooler surface waters are reflected as cooler global surface temperature, but this does not mean that the Earth as a whole is cooling off. On the contrary, less heat is being radiated to outer space. So, the planet is actually storing more heat.

The heat imbalance that the planet is experiencing (about 1.5 watts/m^2) will persist until atmopheric temperature rise significantly. However, since the oceans store most of the heat, we won't fully realize new equilibrium surface temperature until after the ocean have reached equilibrium too.

 

[sylas]

The heat imbalance that the planet is experiencing (about 1.5 watts/m^2) will persist until atmopheric temperature rise significantly. However, since the oceans store most of the heat, we won't fully realize new equilibrium surface temperature until after the ocean have reached equilibrium too.

I agree with the above, except that number 1.5 W/m² for current imbalance. Do you have a reference?

If you are talking about the whole planet, I am pretty sure the imbalance is substantially less than that. But if you can give a reference, I would be very keen to see it, seriously. I'd like to know the basis for the estimate, the time span used, and whether it is a planetary value or over a more limited region -- such as being limited to the ocean surface.

I've got another post in preparation, but I think the real value is probably about a quarter of that. (References and discussion, in [post=2186640]msg #3[/post].)

Cheers -- sylas

 

[Xnn]

I use the 1.5 Watt/m^2 as a rough approximation of the IPCC value:

the effect of human activities since 1750 has been
a net positive forcing of +1.6 [+0.6 to +2.4] W m–2.

See page 31 of the following link: http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-ts.pdf

However, by satellite direct measurements it's larger:

The 5-yr global mean CERES net flux from the standard CERES product is 6.5 W m−2, much larger than the best estimate of 0.85 W m−2 based on observed ocean heat content data and model simulations.

http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175/2008JCLI2637.1

 

[bellfreeC]

What do you mean, "if the data is not adjusted"?

I am kind of curious myself. This first technique I bolded is suppose to be a quicker study.

I have yet to google Arthur Robinson**. I suspect the petition could be signed by anyone, whether they call themselves a scientist or not.

Air-Sea CO2 Flux
by Eddy Covariance Technique in the Equatorial Indian Ocean
Fumiyoshi Kondo and Osamu Tsukamoto

"The raw CO2 fluxes by the eddy covariance technique showed a sink from the air to the ocean, and had almost the same value as the source CO2 fluxes due to the mean vertical flow, corrected by the sensible and latent heat fluxes (called the Webb correction). The total CO2 fluxes including the Webb correction terms showed a source from the ocean to the air, and were larger than the traditional bulk CO2 fluxes estimated by mass balance techniques."

EARTH SCIENCE STUDY GUIDE - Mustapha KANE, Ph.D.


-------
Last week[that was a year ago, I don't believe I heard anything about it through the broadcast medium-MrB.], Dr. Arthur Robinson of Oregon Institute of Science and Medicine announced at the National Press Club in Washington D.C. that over 31,000 American scientists signed a petition rejecting the theory of man-made global warming.

So why is the support for this theory evaporating among scientists? Perhaps it might be due to the fact that global temperature trends have remained flat for the past decade while the levels of carbon dioxide have risen 5.5%.

The foundation of the AGW theory is based on rising carbon dioxide levels producing higher temperatures. Perhaps this evaporating consensus might be due to the analysis of paleoclimate data that reach back hundreds of thousands of years through glacial/interglacial transitions. This analysis showed that changes in Earth's temperature always preceded changes in atmospheric carbon dioxide. How can that be? Well the oceans are a vast reservoir of carbon dioxide. As the oceans warm, it release this gas back into the atmosphere. The atmospheric carbon dioxide levels measured today are primarily of a natural origin rather than man-made.

Or perhaps the global warming theory is in trouble because it is based primarily on a complex computer climate model that is more hype than substance. This sophisticated model fails to include the effects of cloud-cover. Clouds are a major factor in modulating Earth's temperature. Clouds block sunlight, reflecting the light back into space thus lowering temperature. The intensity of the sun's magnetic field controls the rate that high energy particles, called galactic cosmic rays, hit the Earth's atmosphere. These particles seed cloud formation through ionization.

John Ray (M.A.; Ph.D.), writing from Brisbane, Australia.
GREENIE WATCH: 05/01/2008 - 06/01/2008
-------

Speaking of Australia [[Tim Palmer was quoted in the above blog, which is how I came across the 800+kb blogspot a couple of days ago]]... I found this quote in a pdf[link] provided by someone at the ABC network's forum, "There is no sound theoretical basis to expect a reduction in infrared radiation to space in the relatively narrow CO2 wavelength bands to cause an increase in surface temperature."
HEARTLAND INSTITUTE
International Conference on Climate Change: 8-10 March 2009

Heartland Institute's impact level I know not. William Kininmonth does not deny the enhanced temperature effect of extra carbon dioxide [in one graph it is below seventy km]. He, like me, doesn't think there is going to be any out of balance time scale.
Carbon dioxide can be factors higher and only green the Earth. Climate change is basically beyond any worthwhile predictive time scale* or so fungible that it is gibberish.

MrB.
*And Tim Palmer has to call this a "radical" indeed, a "much more radical paradigm"? I think I know why... and I hope to eventually add that to the Physics of Global Warming thread. https://www.physicsforums.com/showthread.php?t=294362

http://www.wilsoncenter.org/index.cfm%3Ffuseaction%3Dwq.essay%26essay_id%3D231274 is a taste...
James Pollard Espy (1785–1860), the first meteorologist employed by the U.S. government, was a frontier schoolmaster and lawyer until he moved to Philadelphia in 1817. ...

His stature has been diminished, however, by his unbridled enthusiasm for rainmaking. Espy suggested cutting and burning vast tracts of forest to create huge columns of heated air, believing this would generate clouds and trigger precipitation. “Magnificent Humbug” was one contemporary assessment of this scheme. Espy came to be known derisively as the “Storm King,” but he was not *deterred.


**I will endeavor to read thread #'s 245897 & 190230.

 

[sylas]

I use the 1.5 Watt/m^2 as a rough approximation of the IPCC value:

Ah! You are mixing up terms. The "forcing" is not the same as the "imbalance" currently being experienced. You are comparing numbers that are measuring completely different quantities.

The key background concept here is the Earth's energy balance. The Earth receives energy from the Sun, and emits energy back out to space, and these two fluxes are maintained in balance, because the Earth has no comparable internal source of energy.

Forcing

A forcing is a change to the balance of energy, but a forcing also produces a response to restore the balance.

The simple account of forcing is this. Suppose something changes to energy flow. It can either be a change in solar input, or in the amount of energy reflected (albedo) or in the capacity of the atmosphere to absorb radiation (greenhouse). The immediate effect is a change in the energy balance, so that there is a difference between what is absorbed and what is emitted.

The response of the planet is to heat up or cool down, and that changes the emission of thermal energy back to a state of balance again.

Forcing is thus a very useful way to quantify the impact of different things that drive temperature change.

A more precise definition of forcing is given in the IPCC 4AR WG-1 "The Physical Science Basis" (Chapter 2, section 2.2, page 133):

[Radiative forcing is] the change in net (down minus up) irradiance (solar plus longwave; in W m^-2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values.​

Imbalance

The "imbalance currently experienced" is the actual difference at a point in time between incoming and outgoing radiation. The imbalance is thus a combination of forcing and response, whereas the forcing very deliberately omits the response of the climate system for restoring balance.

However, by satellite direct measurements it's larger:

The 5-yr global mean CERES net flux from the standard CERES product is 6.5 W m^-2, much larger than the best estimate of 0.85 W m^-2 based on observed ocean heat content data and model simulations.

http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175/2008JCLI2637.1

First, this is not "larger" than the IPCC forcing, because it is measuring something different. Second, and more important, the 6.5 is not an accurate measurement of imbalance, but a demonstration of large errors in satellite derived estimates.

I think you have misunderstood what that paper is doing. The problem is that satellites are not anywhere near accurate enough to measure the imbalance. The fundamental problem being addressed in that paper is the 6.5 W/m² is wildly inaccurate, and they want to clean it up. Quoting the summary of the paper, with my emphasis:

Our best estimate of the average global net radiation at the top of the atmosphere (TOA), defined as the difference between the energy absorbed and emitted by the planet, is 0.85 +/- 0.15 W m^-2 (Hansen et al. 2005). Because of uncertainties in absolute calibration and the algorithms used to determine the earth’s radiation budget, satellite-based data products show a sizeable imbalance in the average global net radiation at the TOA, ranging from -3 to 7 W m^-2.

—Loeb, N.G. et. al. (2009) Toward Optimal Closure of the Earth’s Top-of-Atmosphere Radiation Budget, in Journal of Climate, Vol 22, Iss 3, Feb 2009, pp 748-766​

There's another important point here as well. Loeb et al are focused on clearing up the errors in satellite numbers, but they repeat Hansen's 0.85 estimate without any independent derivation of their own.

Addendum, added in edit. In my opinion, the above extract from Loeb et al should have been picked up in peer-review and sent back for correction. A range of -3 to 7 does NOT show a "sizable imbalance". Just the reverse. It means that no imbalance can be shown within the accuracy of the measurements. The phrase "show a sizable imbalance" should have been replaced by "have substantial differences". It might even be a typo, but as phrased it is nonsensical.

I noted back in [post=2186640]msg #3[/post] that Hansen's estimate is substantially greater that what is indicated from ocean heat content estimates, by Levitus, and Domingues, and others. Here, just for the record, are the relevant references.

• Domingues, C.D. et. al., (2008) Improved estimates of upper-ocean warming and multi-decadal sea-level rise, in Nature Vol 453, pp 1090-1093 (19 June 2008) doi:10.1038/nature07080
• Hansen, J. et. al. (15 authors) (2005) Earth's Energy Imbalance: Confirmation and Implications, in Science, Vol 308, no 5727, pp 1431-1435.
• Levitus, S. et. al., (2009) http://www.agu.org/pubs/crossref/2009/2008GL037155.shtml, in Geophys. Res. Lett., 36, L07608, doi:10.1029/2008GL037155.

I think the paper Hansen et al (2005) can be a bit confusing on this point. If you read it, it is clear that there's a difference between measurements and models, and the 0.85 is model based, higher than measurements, but within credible uncertainities. My own reading of the literature suggests that the mismatch is actually pretty substantial.

Since writing that, I have asked Gavin Schmidt about it, at his blog. Gavin was a co-author of Hansen et al 2005. In the responses I find that Hansen has indeed reduced his estimate in recent lectures, and draws a plain distinction between measurements and models. See, for instance, a talk given by Dr Hansen earlier this year:

Chart 14:

Modeled Imbalance: +0.75 +/- 0.25 W/m²
Ocean Data Suggest: +0.5 +/- 0.25 W/m²​

Now, the ultimate question: can we stabilize climate? We would need to restore the planet’s energy balance. The underlying imbalance (averaging over short-term fluctuations) is probably close to 0.5 W/m².

—Air Pollutant Climate Forcings within the Big Climate Picture, Talk given by J. Hansen at the Climate Change Congress, “Global Risks, Challenges & Decisions”, Copenhagen, Denmark, March 11, 2009​

​

Note that the error bounds here are quite large. He is quoting model numbers here that range from 0.5 to 1.0, whereas in Hansen 2005 the range was 0.7 to 1.0. Personally, I expect that as the dust settles we'll end up with a number a bit less than 0.5. That's not an expert opinion, but an amateur guess based on reading quite a number of different papers working towards nailing this down. I think nearly everyone agrees that the major part of this imbalance corresponds to heating within the upper 700m of the ocean; and the data on that is consistently hovering around 0.25. So it will be more than 0.25, when you consider contributions to stored energy on land and in the deep ocean, but I doubt it can be as much as 0.5.

This is by no means settled business, but it is converging towards a solution. Direct measurements of the heat content have been plagued by instrument problems, and that's still not cleared up.

Cheers -- sylas

 

[sylas]

Speaking of Australia [[Tim Palmer was quoted in the above blog, which is how I came across the 800+kb blogspot a couple of days ago]]... I found this quote in a pdf[link] provided by someone at the ABC network's forum, "There is no sound theoretical basis to expect a reduction in infrared radiation to space in the relatively narrow CO2 wavelength bands to cause an increase in surface temperature."
HEARTLAND INSTITUTE
International Conference on Climate Change: 8-10 March 2009

Heartland Institute's impact level I know not. William Kininmonth does not deny the enhanced temperature effect of extra carbon dioxide [in one graph it is below seventy km].

I've just pulled out a brief extract from the post. The problem is that you are mixing up all kinds of things here, ranging from first rate science to more or less insane pseudoscience.

It's really hard, I appreciate, to follow all the stuff that different people claim. It's hard for a nonexpert to tell what disagreements arise from actual open questions in science, and what disagreements arise from the clash between science and pseudoscience. You'll see both, in full measure, in popular writings and the internet. That's why we are required to use peer reviewed scientific sources here in physicsforums. It cuts out a lot of the nonsense straightaway.

Dr Tim Palmer is a first rate scientist, dealing with important open questions.

The Heartland Institute is a notorious and enthusiastic purveyor of pseudoscientific nonsense, dressed up as a parody of the real thing. They mix up good and bad without any apparent discrimination, and are completely unreliable as a source.

The quote you give here from Kininmonth (starting out "no sound theoretical basis") is scientifically on a par with claims that the Earth is 6000 years old.

It is impossible to overstate just how ridiculous that claim is.

Any undergraduate course on radiation and the atmosphere will deal with changing absorption of thermal radiation with increasing greenhouse gas concentrations. The impact of CO2 is one of the more straightforward. It has a large window of absorption close to the peak of Earth's thermal emission spectrum, and with increasing concentrations there is additional absorption primarily in the wings of the absorption band. The effect can be calculated, as a forcing, to quite good accuracy, using basic physics that is in no doubt whatsoever.

I have explained more about how absorption works in [post=2165483]msg #3[/post] of thread "Estimating the impact of CO2 on global mean temperature".

Please don't just drop large piles of random claims into the thread. Stick to legitimate scientific references, and try to relate it to some identifiable coherent point, directly related to the specific topic of the thread.

Cheers -- sylas

PS. I've looked up a bit more about William Kininmonth. He's a loony. He describes himself as "Director of the Australasian Climate Research Institute". That turns out to be a trading name set up by William Kininmonth, which he runs out of his own private residence. It is typical of the Heartland Institute that they'd pick up this kind of stupidity and include it uncritically in their ludicrous "conference".

 

[bellfreeC]

The Heartland Institute is a notorious and enthusiastic purveyor of pseudoscientific nonsense, dressed up as a parody of the real thing.

All right, don't hold back. :)

The quote you give here from Kininmonth (starting out "no sound theoretical basis") is scientifically on a par with claims that the Earth is 6000 years old.

It is impossible to overstate just how ridiculous that claim is.

<Snip=[on the more direct importance of "forcing" thread id:307685]++>

PS. I've looked up a bit more about William Kininmonth. He's a loony. ...

Well, a loon implies that he knows not[what he says] rather than a master magician who knows better.

Anyway, I see thread id:245897 is in forum=20. That maybe the place for any more comments on motives.

However, as I have read that thread{almost finished}, Andre is making much the same claim in that we know enough to have a paradigm dominance where measurements are not second class to climatic models.


Andre Sep22-08
t=245897msg=40
"with all due respect you have a motive for that. Physical realities don't have motives. It's just there, whether we like it or not. Remember Richards Müller most important observation:

Let me be clear. My own reading of the literature and study of paleoclimate suggests strongly that carbon dioxide from burning of fossil fuels will prove to be the greatest pollutant of human history. It is likely to have severe and detrimental effects on global climate. I would love to believe that the results of Mann et al. are correct, and that the last few years have been the warmest in a millennium.

Love to believe? My own words make me shudder.

...

Moreover in the water vapor feedback to keep relative humidity constant, it can be calculated that this takes just about as much energy as was required to cause the extra warming."

Andre[Sep20-08] also points to his thread id:252066,
"CO2 cooling?".

I changed the quote slightly from what Andre provided of Müller.
The age of the Earth and Man's place on it does come in and more important for a true understanding of the Coriolis effect\cause can there be any real evidence that the Earth rotates with terms fixed on an energy budget?

MrB.

++Although, I would note that I chose that sentence of Kininmonth's because it spoke of narrow bands. This would be something basic. Further the word "shoulder" is also used for "wings" I know. But what don't I know...? And would the "CO2 cooling?" thread help draw down the loony quotient or does it do the opposite, Sylas? That is another thread I need to finish reading!

 

[joelupchurch]

I noticed that Roger Pielke Sr. comments extensively on Leviticus et al. in his May 18th blog entries http://climatesci.org/". I notice he refers to post 2003 trend as a "lack of warming", rather than a cooling.

Based on some things I read that indicate we are going into a new El Nino cycle, I expect a warming trend to resume next year, assuming we come out of the current solar minimum this year.

 

[Richard111]

Please excuse a confused layman's question.
I found this graph: http://omlc.ogi.edu/spectra/water/gif/segelstein81.gif

and similar here: http://www.lsbu.ac.uk/water/vibrat.html (scroll down)

It is possible (probable) I am misinterpreting this data. It appears to me that infrared radiation above 4 microns has no heating effect on water but possibly an increase in water vapour release.

This indicates to me that the oceans are heated by sunlight only (below 3 microns) and greenhouse gases play no part in heating over 70% of this planet. This would also apply to all rivers and inland waters.

Increased water vapour = increased cloud cover = reduced solar radiation at sea level = eventual reduction in ocean heat. All in all, a self regulating negative feedback system.

Regards

Richard

 

[sylas]

Please excuse a confused layman's question.
I found this graph: http://omlc.ogi.edu/spectra/water/gif/segelstein81.gif

and similar here: http://www.lsbu.ac.uk/water/vibrat.html (scroll down)

Nice diagrams. Thanks for the links...

It is possible (probable) I am misinterpreting this data. It appears to me that infrared radiation above 4 microns has no heating effect on water but possibly an increase in water vapour release.

The energy of sunlight all gets absorbed (less what is reflected). In shallow water a few meters deep, you still get plenty of visible light penetrating to the bottom, where it heats the floor; and then the water gets heated from there by convection. In deep water nearly all radiant energy is absorbed within a couple of hundred meters.

From your diagrams, there's not much radiant energy getting below 10m, and below 100m it's going to be quite dark, as nearly all the light gets absorbed by then.

Water vapour depends on the temperature of the surface, mostly, but any energy taken into those upper layers will contribute to a warmer surface. The two go together. You get water vapour by heating water.

This indicates to me that the oceans are heated by sunlight only (below 3 microns) and greenhouse gases play no part in heating over 70% of this planet. This would also apply to all rivers and inland waters.

This is a non-sequitur. Greenhouse effects apply in precisely the same way over land and over ocean. They are determined by the atmosphere, not the surface, and they result in a greater flux of infrared radiation down to the surface from the atmosphere at around 10 μm, just where water absorbs energy most effectively. This is no accident... water is the strongest greenhouse gas in the atmosphere.

Greenhouse gases are not a direct source of energy in their own right. They are like a blanket in this respect. All the energy, ultimately, is from the Sun. What greenhouse gases do is absorb some of the thermal radiation coming up from the surface, and this makes it harder for energy to get out to space. So the surface heats up more, until it is hot enough to shed the energy it absorbs back to space.

Another completely equivalent way of considering this is "backradiation". By Kirchhoff's law, gases emit strongly in the same wavelengths that they absorb; and they radiate in all directions. The end result is that there is a large flux of energy coming down from the atmosphere... though by the second law it is not as much as is going up from the surface. The atmosphere is heated from the surface, and this is just another way of saying that the atmosphere makes it harder for the surface thermal radiation to get out into space.

The additional flux of thermal radiation coming down to the surface peaks around 10 microns.

Increased water vapour = increased cloud cover = reduced solar radiation at sea level = eventual reduction in ocean heat. All in all, a self regulating negative feedback system.

You have correctly identified an important negative feedback process.

However, there's a lot more to cloud than this effect. It's one of the hardest parts of the whole climate issue to model physically. Clouds are very good at absorbing thermal radiation, as well as reflecting sunlight. This means that they add considerably to the greenhouse effect themselves. Think about night time -- which is just as important as the day for averaging temperatures. A clear night is much colder than a cloudy one, and that is because clouds have such a strong interaction with thermal radiation. The effect of cloud depends very strongly on their altitude and composition. In general, cloud feedback is thought to be a net positive feedback; although with the largest uncertainty of any climate feedback process, to the extent that we can't be sure it is a net positive.

But the most important factor for water vapour, by far, is its direct greenhouse effect by infrared absorption in the atmosphere generally. If you look at your diagrams, to the right of the visible light band, you see water absorbing 10 μm very effectively, and that is right where Earth's main thermal emissions lie. This positive feedback is the strongest part of the effect of water vapour.

Reference: Bony, S. et. al. How Well Do We Understand and Evaluate Climate Change Feedback Processes?, in J. of Climate, Vol 19, 1 Aug 2006, pp 3445-3482.

Bony et al give the water related feedback estimates (mean and standard deviation) as follows (measured in W/m²/K)

• Water vapour direct feedback: 1.8 +/- 0.18
• Lapse rate feedback: -0.84 +/- 0.26
• Cloud feedback: 0.69 +/- 0.38

As you can see, the cloud feedback estimate is less than two standard deviations away from zero, so the sign is actually uncertain. Water vapour direct effects are strongly anticorrelated to lapse rate effects, so when combined their uncertainty is actually reduced. All told, the water vapour plus lapse rate feedback is dominant, but there's a lot of ongoing work to try and constrain cloud feedbacks better, since they are the major source of uncertainity.

Cheers -- sylas

 

[chriscolose]

I think that Richard's point was more so that shortwave radiation "penetrates more" into the water layer than does longwave (infrared) radiation. It does, but this doesn't mean infrared doesn't heat water, or that it isn't as important a term. The top 100 m or so of ocean is well stirred by turbulence, so energy dumped into the top skin layer gets mixed downward rapidly. It isn't as though the greenhouse effect suddenly shuts off as you move from land to water.

Furthermore, the enhanced greenhouse effect from anthropogenic activities results not only in enhanced downward infrared emission, but all the heat fluxes which couple the air to the surface. The increased downward emission is more so due to higher temperatures than it is directly due to higher CO2 levels, since the whole troposphere more or less warms up together.

As far as clouds, many models and limited observation suggests decreases of low cloud cover in a warmer climate, or at least a greater increase in high cover relative to low cloud cover changes (i.e., a positive feedback). As sylas noted, this is a very active topic of research and not limited to "more water vapor = more clouds," particularly since cloud formation is not determined by absolute amounts of vapor, but rather by relative humidity, which changes little on a global scale. The sign of cloud impact depends on height, latitude, optical thickness, and other things. Hartmann's FAT hypothesis (probably the leading competitor to the IRIS proposal by Lindzen et al) has high cloud top temperature changing little, which decouples the emission temperature from the surface temperature and becomes a positive feedback.

 

[joelupchurch]

I'm not comfortable with how they mix in the lower quality pre argo data. There seems to be a sharp change in the trendline around 2004. Is that real or just because they are mixing apples and oranges?

Excuse me for referencing whatsupwiththat, but it looks like I wasn't the only one who thinks the transition from preargo to argo data didn't look right. It looks like there is a problem stitching the two datasets together. If you look at the 3 month line, the change is almost all in one quarter. I was a year off reading the scale, since the post references 2002-3, not 2004.

http://wattsupwiththat.com/2009/06/02/anomalous-spike-in-ocean-heat-content/#more-8132"

 

[Richard111]

Thank you sylas #36 and thank you chriscolose #37, that was indeed my point. When I read the http://www.climates.com/SPECIAL%20TOPICS/GW/greenhouse.htm I imagined the top skin of water would vaporise. (I know it doesn't as I live by the sea.)

For heat energy reaching the surface of the Earth from all sources, the budget is as follows:

1. 34.1% comes from the Sun as direct and diffuse solar radiation (insolation). Of this amount, 20.1% is as direct solar radiation, and the remaining 14.0% as diffuse solar radiation.

2. 65.9% comes from the “greenhouse” gases of the atmosphere. Of this amount, 40.0% is from water in its various phases, 14.1% from carbon dioxide, and the remaining 7.8% from ozone and oxygen.

I must go and read up on surface turbulance and heat distribution in water.

Regards

Richard

 

[Richard111]

Well my ignorance was politely pointed out by email that liquid water responds to IR like any other substance that is opaque to IR, in fact better because of the conductive ability of water. IR, in time, will warm a brick, which is opaque to IR. (sigh) Its a long hard learning curve.

 

[Patriot Vet]

relative humidity, which changes little on a global scale.

It has been changing a lot for the past 50 years, globally. Dropping 21% in fact.

http://www.cdc.noaa.gov/cgi-bin/data/timeseries/timeseries1.pl"

Also documented by:
‘http://www.theclimatescam.se/wp-content/uploads/2009/03/paltridgearkingpook.pdf" ’ by Garth Paltridge, Albert Arking and Michael Pook

ABSTRACT:

Water vapor feedback in climate models is positive mainly because of their roughly constant relative humidity (i.e., increasing q) in the mid-to-upper troposphere as the planet warms. Negative trends in q as found in the NCEP data would imply that long-term water vapor feedback is negative—that it would reduce rather than amplify the response of the climate system to external forcing such as that from increasing atmospheric CO2.

Discussion:

First, the observations of relative humidity RH do not support the proposition that emerges from the behavior of general circulation climate models that the value of RH at any given height in the troposphere remains fairly constant under the influence of global warming (e.g., Soden and Held 2006; Pierrehumbert et al. 2007).

 

[sylas]

It has been changing a lot for the past 50 years, globally. Dropping 21% in fact.

This is looking at the wrong thing. You need to look at specific humidity, not relative humidity. The drop in relative humidity is mainly because of the rise in temperature. But feedbacks depend on the amount of water...

You've actually put your finger on one of the reasons the feedback from clouds is not as strong a negative feedback as suggested above. Cloud depends largely on relative humidity.

But the much stronger water vapour feedback depends on specific humidity, which has been increasing -- though the year to year variation is very high so measurements come with substantial uncertainty.

There are some major problems with your data source. You are using the NCEP/NCAR reanalysis data... which is not actually measurement. It is a climate model, which attempts to give a detailed climatology constrained by measured data, but the actual data given is the model, and it has known issues.

It comes with many caveats, and it's particularly dubious as a substitute for measurement of one particular aspect of the climate system.

The actual science on this indicates increasing moisture in the upper troposphere, where the feedback effect is strongest. Note that these results are consistent with reducing relativity humidity. Remember... it is specific humidity that gives the feedback, and as temperatures rise you get more water and more feedback even as relativity humidity may be dropping.

Refs:

• Soden, B.J. et al. http://www.sciencemag.org/cgi/content/abstract/310/5749/841, in Science, Vol. 310. no. 5749, pp. 841 - 844, (4 Nov 2004).
• Dessler, A.E. and Sherwood, S.C., http://geotest.tamu.edu/userfiles/216/dessler09.pdf in Science, Vol 323, no. 5917, pp. 1020 - 1021 (20 Feb 2009)

 

[chriscolose]

Patriot Vet,

I don't agree with sylas that RH is not something important to look at, mainly because while the actual water vapor feedback depends on specific humidity, the constancy of relative humidity tells you how well the change saturation vapor pressure follows expected changes from Clausius-Clapeyron. The relative humidity is roughly balanced by increases in temperature and increases in moisture. A decrease in relative humidity however does not a priori mean a negative feedback. But he is correct that this particular data is not very useful, and in fact probably worthless in determining the long-term humidity trends (see Trenberth, Fasullo and Smith 2005 and the Soden et al paper referenced above for discussion). I have blogged about the Paltridge paper and the corresponding discussion on other secondary sources, but it's probably not worth going into in more detail because it is not something that is going to change our picture of the subject and is not a useful contribution to further understanding of water vapor feedback or humidity trends. Sylas' two references are good ones to look at.

 

[sylas]

... I don't agree with sylas that RH is not something important to look at, ...

That was not my intended implication; and I am glad to accept the correction. Thanks.

My point is that it is the wrong thing to look at for water vapour feedback, which depends on the total amount of moisture in the air: specific humidity.

However, looking over the thread I see that patriot vet was actually quoting chris colose on relativity humidity and cloud feedback... and of course relative humidity is important for cloud feedback.

My understanding of the data is that there is indeed a small overall trend of reducing relative humidity, but considerable regional variation in trend. This is based on direct measurement, rather than the model based NCEP/NCAR reanalysis product, which is a poor guide.

So where are we. Richard raised the matter of feedback processes associated with water vapour. This is complex, as there are multiple effects involved.

For a useful short background and summary of the current state of knowledge, I recommend the paper cited above: http://geotest.tamu.edu/userfiles/216/dessler09.pdf . This is a short and clear review article specifically about empirical constraints on feedback processes associated with water vapour. The conclusion is that theory and observation imply a strong positive feedback; and the magnitude is most likely about 1.5 to 2.0 W/m²/K. This refers to the main water vapour feedback.

This positive feedback might be offset by a weaker negative feedback from increased cloud cover. This feedback is particularly hard to constrain, but estimates are that it is actually an additional positive feedback; and a part of the reason for this is that cloud depends in relative humidity rather than specific humidity. Relative humidity shows considerable regional variation (Dressler et al 2009 again) so a single trend gives the wrong idea. But over all, the is probably a net fall where it matters, and this contributes to cloud being an additional net positive feedback on top of the strong positive water vapour feedback.

Cheers -- sylas

 

[joelupchurch]

I think Patriot Vet has a point. If RH is dropping then the positive forcing is probably at the low end of the range that the IPCC is using. That would give a warming of 0.2 degrees centigrade per decade or even lower.

That doesn't change the ultimate problem, but gives you a lot more options for solutions.

What is really interesting is the back story on the Paltridge paper. You can read about it here:

http://www.climateaudit.org/?p=5416"

 

[chriscolose]

I think Patriot Vet has a point. If RH is dropping then the positive forcing is probably at the low end of the range that the IPCC is using. That would give a warming of 0.2 degrees centigrade per decade or even lower.

That doesn't change the ultimate problem, but gives you a lot more options for solutions.

What is really interesting is the back story on the Paltridge paper. You can read about it here:

http://www.climateaudit.org/?p=5416"

It would be very nice to stick with refereed sources or something from ".edu" and similar-quality sites. I understand that it is very "sexy" to blog about how all those AGW people are ignoring their paper, silencing dissenting views, or what have you. The fact is that if this paper is brushed to the side then the experts who actually study these things have reasons to brush it to the side, perhaps reasons which neither Paltridge or McIntyre are aware of. It may surprise some but many papers (either good or bad) in the literature are just not very important. In some cases it may be best to just tell them why their paper is not very important, or why it does not offer robust conclusions, or why other evidence is better and leave it at that.

//"--------------------------------------------------------------------------------
I think Patriot Vet has a point. If RH is dropping then the positive forcing is probably at the low end of the range that the IPCC is using"//

This really has nothing to do with the forcing, but rather the strength of the water vapor feedback, which has been the subject of study for many decades. The general picture has not changed very much.

Estimates of climate sensitivity come from the paleoclimate record and suggest that on the timescales relevant to anthropogenic perturbations, the climate is dominated by positive feedback and the equilibrium response to a doubling of CO2 is roughly 2 to 4.5 C. Evidence accumulated over the past few decades has done a good job putting constraints on various feedbacks, clouds still remaining at a very unacceptable status of understanding. Modelling and limited observations suggest decreases in low cloud cover in a warming climate. Some of the "feedback" is not actually a feedback in the traditional definition of being a response to the temperature anomaly, but rather is a rapid response to the increased forcing from CO2 independent of deltaT. If the overall cloud feedback is negative, it does not appear to be very strong.

 

[sylas]

Chris beat me to it... but since I had started writing this I'll post anyway.

I think Patriot Vet has a point. If RH is dropping then the positive forcing is probably at the low end of the range that the IPCC is using. That would give a warming of 0.2 degrees centigrade per decade or even lower.

Humidity makes no difference to forcing. I presume you meant "feedback" there, which in turn determines the climate sensitivity.

The relative humidity does not have much effect on feedback. The feedback is mainly from specific humidity (Dressler 2009). I don't believe that the humidity data is accurate enough to constrain sensitivity measurements beyond the range given in the literature and IPCC reports. If anything, the work coming out on humidity is making the low end of the range LESS likely... but with the kind of uncertainties that are reflected in having a large range of possible sensitivities.

Some references:

• Soden, B.J. et. al. (2006) An Assessment of Climate Feedbacks in Coupled Ocean–Atmosphere Models, in J. of Climate, Vol 19, July 2006, pp 3354-3360.
• Bony, S. et. al. (2006) How Well Do We Understand and Evaluate Climate Change Feedback Processes?, in J. of Climate, Vol 19, 1 Aug 2006, pp 3445-3482.
• Dessler, A.E. el. al. (2008) http://geotest.tamu.edu/userfiles/216/Dessler2008b.pdf , in Geophys Res Lett, Vol 35, L20704, doi:10.1029/2008GL035333, (2008).
• Dessler, A.E. and Sherwood, S.C., (2009) http://geotest.tamu.edu/userfiles/216/dessler09.pdf in Science, Vol 323, no. 5917, pp. 1020 - 1021 (20 Feb 2009)

IPCC sensitivity values are 2.0 to 4.5 K per CO2 doubling. Sometimes 1.5 is given as the low end of the range. Using W/m² as the forcing units, and 3.7 W/m² for a doubling, that is around 0.5 to 1.2 K per W/m².

The relationship between sensitivity and feedbacks is explained in Bony et al (2006). Basically, it works like this. Let F be a forcing, and T be a temperature. The feedback basically like a forcing you get from temperature, and is given as λ. There's a basic Planck no-feedback response (λ_P, or sometimes λ₀). The equilibrium response to forcing is given by the equation

F + (\lambda_P + \lambda) T = 0​

The Planck response is negative (higher temperature result in more emitted energy) with a value of -3.2 W/m²/K. The sensitivity is simply T/F. If we let s be the sensitivity in K per W/m², then

\begin{align*}<br /> s = T/F &amp;= \frac{-1}{-3.2 + \lambda} \\<br /> \frac{1}{s} &amp;= 3.2 - \lambda \\<br /> \intertext{Hence}<br /> \lambda &amp;= 3.2 - \frac{1}{s}<br /> \end{align*}​

Low sensitivity means low feedback parameter. Sometimes rather than the sensitivity s in K per W/m², a paper focusing on feedbacks might just give the total feedback which is the negative inverse of s. This is done in Soden (2006), for example.

Here are the values for feedback and sensitivity, at the high and low ends of the range.

\begin{array}{r|llll}<br /> &amp; \mbox{sensitivity} &amp; \mbox{sensitivity} &amp; \mbox{feedback and base response} &amp; \mbox{feedback} \\<br /> &amp; &amp; &amp; \lambda+\lambda_P &amp; \lambda \\<br /> \mbox{units:} &amp; K/\mbox{2xCO2} &amp; K W^{-1} m^2} &amp; Wm^{-2}K^{-1} &amp; Wm^{-2}K^{-1} \\<br /> \hline<br /> \mbox{IPCC v. low}&amp;1.5&amp;0.41&amp;-2.47&amp;0.73\\<br /> \mbox{IPCC low}&amp;2&amp;0.54&amp;-1.85&amp;1.35\\<br /> \mbox{Soden low}&amp;2.31&amp;0.63&amp;-1.6&amp;1.6\\<br /> \mbox{Soden high}&amp;4.11&amp;1.11&amp;-0.9&amp;2.3\\<br /> \mbox{IPCC high}&amp;4.5&amp;1.22&amp;-0.82&amp;2.38<br /> \end{array}​

The numbers from Soden (2006) are theoretical (model based) expected values. The largest feedback is the water vapour feedback, from about 1.5 to 2.1 W/m²/K (table 1, page 3355).

When compared with empirical measures of humidity, estimates of water vapour feedback are at the high end, rather than low end. Dressler et. al. (2008) estimates 2.04 from recent empirical data, but with substantial variation, from 0.94 to 2.69.

What is really interesting is the back story on the Paltridge paper. You can read about it [...snip...]

I strongly recommend we do NOT go into secondary speculations from blogs about "back stories". I'm very tempted to go down this side track, but let me just say that this blog link is a perfectly dreadful way to get the so-called "back story". What you have there is mostly a bad case of sour grapes over a paper with little relevance or value to the realities of climate, given its ... odd ... choice of data and methodology. It would be easy to see OTHER perspectives on this alleged "back story", but let's avoid that whole quagmire and stick to the science please... and the forum guidelines.

Paltridge et al is NOT using empirical measurement, but a model based reanalysis product. The NCAR/NCEP reanalysis is useful for various applications when used with due regard for its limitations. Unfortunately it has also been used for a lot of poorly founded inference that conflicts when more credible science properly based on empirical measurement directly. The paper itself tends to acknowledge the limits of the approach rather better than the pundits and bloggers who have picked it up and inflated its significance.

Cheers -- sylas

 

[joelupchurch]

Normally, I wouldn't reference a blog posting, but since this was an actual quote from the author of the paper, I decided to mention it. If it had just been a comment by Steve McIntyre, I wouldn't have brought it up.

When I see a paper mentioned, I usually check Google Scholar and see if there is a place I can download it for free and see what other papers reference it and what the other papers say. That didn't work, so I did a regular search and found the statement by the author. The statement by the reviewer was so biased that I found it remarkable that the editor didn't get another scientist to review the paper.

I looked at IPCC AR4 and section "3.4.2.2 Upper-Tropospheric Water Vapor" and there are multiple places where they say the observations are consistent with a constant Relative Humidity. That implies to me that if the RH is decreasing, that the Specific Humidity is increasing by less than expected.

As to the comment about NCAR/NCEP being a "model based reanalysis product", I should point out that applies to most of the data we are dealing with. When dealing with data collected over a period of decades, I don't see how that can be avoided. I'm not clear about why radiosonde data has more issues than the buoy data this thread started with.

I can accept that the data, especially the older data, has a high uncertainty. I made comments about pre-1970 buoy data being almost useless for this reason. But when the results show decreases in RH at every pressure over a period of decades, then explanations about this sort of bias could have creep in are in order instead of just saying the data is suspect. I looked at Wang et al., 2002a, but it isn't clear why issues with one model of radiosonde would justify discarding 50 years of data.

 

[sylas]

Normally, I wouldn't reference a blog posting, but since this was an actual quote from the author of the paper, I decided to mention it. If it had just been a comment by Steve McIntyre, I wouldn't have brought it up.

Understood -- and if the focus was on the actual science then I would be more interested. But as you said: it's all about the "back story", which means he's bellyaching about reviewers and editors. Pretty poor, IMO. There's two sides to that, and neither of them are about the science.

In any case, Paltridge DID get his paper published, albeit in a less prestigious journal. The reference is:

• Paltridge, G. et. al. (2009) Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data, in Theoretical and Applied Climatology, online Feb 2009, doi 10.1007/s00704-009-0117-x.

The major defect with this work stands out immediately in the abstract: his results are largely inconsistent with satellite data, and rely on a reanalysis which (for humidity) is based on balloon data that he identifies right from the start as "notoriously unreliable". But rather than focus identifying inaccuracies, he seems to focus on what it would mean if they were correct. What the...? My reaction would probably be pretty much the same as the reviewer he called "hysterial".

When I see a paper mentioned, I usually check Google Scholar and see if there is a place I can download it for free and see what other papers reference it and what the other papers say. That didn't work, so I did a regular search and found the statement by the author. The statement by the reviewer was so biased that I found it remarkable that the editor didn't get another scientist to review the paper.

There were other scientists reviewing the paper; and although Paltridge objects, I'm inclined to think the anonymous reviewer quoted may have nailed it. The approach of the paper is very odd indeed, and there's nothing improper about a reviewer making such judgments. It is part of the job. Reviews are MEANT to weed out most submissions to a journal. I take with a grain of salt Paltridge's claim that the editor should have ignored such a review. I've been involved in journal review (maths and computer science), and in my experience there's no problem with strongly negative reviews... only with wildly inconsistent reviews. We're not in a position to judge that; and speculations by all kinds of bloggers who have picked up on Paltridge's objections have jumped to conclusions about reasons for rejecting the paper that they are in no position to make. We can now judge the paper itself on its merits, and it's no surprise to me at all that it was rejected by Journal of Climate. Good for them.

I looked at IPCC AR4 and section "3.4.2.2 Upper-Tropospheric Water Vapor" and there are multiple places where they say the observations are consistent with a constant Relative Humidity. That implies to me that if the RH is decreasing, that the Specific Humidity is increasing by less than expected.

Two issues here. First and most importantly, there's no good reason to think there's a strong decrease in relative humidity. Paltridge is using data known to be inaccurate, which makes the whole exercise something of a waste of time.

Second: there's no particular "expectation" for constant relative humidity. The expectation is rather than the change in RH is small. That fits observations. There IS some evidence of small decreases in relativity humidity; though with sufficient uncertainty that observations are consistent with constant relative humidity. Some models involve increases, and some involve decreases, but none involve large changes.

What section 3.4.2.2 actually does (page 273) is start out by noting explicitly that humidity is uncertain, and then give a quick list of various different results. It cites Wang for evidence of increases in relative humidity, and Minschwaner and Dessler for decreases in relative humidity; then small trends both increasing and decreasing in relative humidity from Bates and Jackson, and others. The major implication is that changes in relative humidity are comparatively small... and that means specific humidity must be increasing, given the temperature trends.

My understanding is that ongoing work tends to be along the lines of Minschwaner and Dessler, for a small decrease in relative humidity.

The top of page 273, right column, is particularly relevant, since it describes the errors in radiosonde data, and the difficulty in developing accurate corrections. Satellite data is generally more reliable, though any measurements over an entire atmosphere have difficulties. Basically this is the reason for Paltridge's results... the data he's using is known to be inaccurate and lacks good error correction approaches. The trends in the graph provided in this thread don't actually mean anything much.

There is also substantial regional variation in humidity trends.

As to the comment about NCAR/NCEP being a "model based reanalysis product", I should point out that applies to most of the data we are dealing with. When dealing with data collected over a period of decades, I don't see how that can be avoided. I'm not clear about why radiosonde data has more issues than the buoy data this thread started with.

Flatly wrong. There's a drastic difference between empirical measurement and model based reanalysis. Most of the data we are dealing with is NOT a model based reanalysis, but is based on empirical data, with clearly identified differences between different instruments.

I don't know why or how you are comparing atmospheric radiosondes with bouys in the ocean. Every measurement has its own sources of error. The IPCC report clearly tells you the basis of problems with radiosondes for humidity measurement. From page 273:

In general, the radiosonde trends are highly suspect owing to the poor quality of, and changes over time in, the humidity sensors.​

The proper comparison here is radiosondes and satellites; and it looks pretty clear that for humidity, the satellites are more reliable.

I can accept that the data, especially the older data, has a high uncertainty. I made comments about pre-1970 buoy data being almost useless for this reason. But when the results show decreases in RH at every pressure over a period of decades, then explanations about this sort of bias could have creep in are in order instead of just saying the data is suspect. I looked at Wang et al., 2002a, but it isn't clear why issues with one model of radiosonde would justify discarding 50 years of data.

I've had a look also, now. Here's the reference for others:

• Wang, J.H. et al. (2002) Corrections of humidity measurement errors from the Vaisala RS80 radiosonde – Application to TOGA COARE data, in J. Atmos. Ocean. Technol., vol 19, pp 981–1002.

I don't know what you mean by "discarding". This is data that is used as best they can, and people are continuing to try and improve the error corrections. This is hard; and it means quite simply that we don't have a good picture of relative humidity trends before satellite records became available. It doesn't mean that data is simply discarded. The thing is that you have to know the problems with what you are using and give due caution to the inferences you might draw. And for times when you've got better data, then you prefer conclusions based on better data.

Note that the papers trying to measure feedback magnitudes are not trying to project back into the past without valid data. They are simply using the period when there IS good data available sufficient to help constrain sensitivity. There's no good reason at all to think that sensitivity was drastically different before we had satellite humidity measurements; only that we don't have the kind of detail in that time that would allow useful constraints to be inferred.

As for corrections: note that they work better in the lower troposphere than the upper troposphere. For more detail... and for the comparisons indicating the superior reliability of satellite data, see:

• Soden B.J. (2004) An analysis of satellite, radiosonde, and lidar observations of upper tropospheric water vapor from the Atmospheric Radiation Measurement Program in J. Geophys. Res. Vol 109, D04105, doi:10.1029/2003JD003828.

Cheers -- sylas

 

[sylas]

There is a new paper just out on heat content of the world ocean. I'll summarize the results as I understand them, in the context of numbers from earlier in the thread.

Since writing that, I have asked Gavin Schmidt about it, at his blog. Gavin was a co-author of Hansen et al 2005. In the responses I find that Hansen has indeed reduced his estimate in recent lectures, and draws a plain distinction between measurements and models. See, for instance, a talk given by Dr Hansen earlier this year:

Chart 14:

Modeled Imbalance: +0.75 +/- 0.25 W/m²
Ocean Data Suggest: +0.5 +/- 0.25 W/m²​

Now, the ultimate question: can we stabilize climate? We would need to restore the planet’s energy balance. The underlying imbalance (averaging over short-term fluctuations) is probably close to 0.5 W/m².

—Air Pollutant Climate Forcings within the Big Climate Picture, Talk given by J. Hansen at the Climate Change Congress, “Global Risks, Challenges & Decisions”, Copenhagen, Denmark, March 11, 2009​

​

Note that the error bounds here are quite large. He is quoting model numbers here that range from 0.5 to 1.0, whereas in Hansen 2005 the range was 0.7 to 1.0. Personally, I expect that as the dust settles we'll end up with a number a bit less than 0.5. That's not an expert opinion, but an amateur guess based on reading quite a number of different papers working towards nailing this down. I think nearly everyone agrees that the major part of this imbalance corresponds to heating within the upper 700m of the ocean; and the data on that is consistently hovering around 0.25. So it will be more than 0.25, when you consider contributions to stored energy on land and in the deep ocean, but I doubt it can be as much as 0.5.

This is by no means settled business, but it is converging towards a solution. Direct measurements of the heat content have been plagued by instrument problems, and that's still not cleared up.

The new paper is:

• von Schuckmann, K., F. Gaillard, and P.-Y. Le Traon (2009), http://www.agu.org/pubs/crossref/2009/2008JC005237.shtml, J. Geophys. Res., 114, C09007, doi:10.1029/2008JC005237

Abstract:

Monthly gridded global temperature and salinity fields from the near-surface layer down to 2000 m depth based on Argo measurements are used to analyze large-scale variability patterns on annual to interannual time scales during the years 2003–2008. Previous estimates of global hydrographic fluctuations have been derived using different data sets, partly on the basis of scarce sampling. The substantial advantage of this study includes a detailed summary of global variability patterns based on a single and more uniform database. In the upper 400 m, regions of strong seasonal salinity changes differ from regions of strong seasonal temperature changes, and large amplitudes of seasonal salinity are observed in the upper tropical and subpolar global ocean. Strong interannual and decadal changes superimpose long-term changes at northern midlatitudes. In the subtropical and tropical basin, interannual fluctuations dominate the upper 500 m depth. At southern midlatitudes, hydrographic changes occur on interannual and decadal time scales, while long-term changes are predominantly observed in the salinity field. Global mean heat content and steric height changes are clearly associated with a positive trend during the 6 years of measurements. The global 6-year trend of steric height deduced from in situ measurements explains 40% of the satellite-derived quantities. The global freshwater content does not show a significant trend and is dominated by interannual variability.[/color]​

What this means is that they've looked at data from the Argo floats, which we've mentioned in the thread. The paper looks at seasonal variations, and also finds a strong increase in heat content over the 6 years of the study period.

In the paper, the heat content is given in units per square meter, and I think this is for the world ocean; not the whole surface of the Earth. The study is "gridded", which means that they are looking closely at different areas; and also different depths, and finding patterns of change. They also obtain totals by integrating over all regions.

Over the six years 2003-2008 inclusive, there is a trend in total heat content for the upper 2000m of ocean corresponding to 0.77 W/m² +/- 0.11. Since this is over the world ocean, to compare with the numbers used previously in the thread we need to multiply by about 0.7; the proportion of the Earth's surface than is ocean. This gives 0.54 W/m² +/- 0.08.

These figures mean that global warming has been continuing over this period; and that when the ocean heats up enough to shut off the energy flow, there will be another 0.54 W/m² of forcing expressed as a surface temperature, just based on what changes have already taken place up to this point.

In the conclusion of the paper, they compare with Levitus et al (2009) which was introduced in [post=2186603]msg #2[/post] of the thread, and discussed in following posts. Joel, in [post=2188093]msg #6[/post], mentions the fact that the ocean heat content numbers from Levitus et al (2009) have a sharp rise around 2003 and then flatten out a bit. This is seen in figure 1 of that paper, also displayed in [post=2188248]msg #10[/post], but described simply as ocean heat content, which was not strictly accurate. It is the heat content of the upper 700m.

The same plateau effect is mentioned here, in the conclusion of the new paper:

During the 6 years of in situ measurements, an oceanic warming of 0.77 ± 0.11 W m−2 occurred in the upper 2000 m depth of the water column. This number is roughly consistent with the 10-year heat content time series published by Willis et al. [2004]. Although this represents a significant increase in the rate of warming, the updated long-term study of Levitus et al. [2009] shows that the upper ocean (0–700 m) heat content increases to a plateau during 2004–2007, i.e., in the time domain of our study.[/color]​

Cheers -- sylas