Is the Faint Young Sun Problem Solved by Increased Greenhouse Gases?

[Wax]

I'm just wondering if Global Warming is considered a fact within the science community? I'm not talking about man made global warming, just global warming in general whether it be caused by nature or man.

 

[Xnn]

Yes; it's a fact.

Global surface temperatures are rising as is the
temperature of the Oceans to several hundred meters while
there is an overall melting of ice and permafrost.

Sea levels are rising (actually accelerating) as expected primarily
from the thermal expansion with a contribution from melting ice.

The global average surface temperature has
increased, especially since about 1950. The updated
100-year trend (1906–2005) of 0.74°C ± 0.18°C

The world ocean has warmed since 1955, accounting
over this period for more than 80% of the changes in
the energy content of the Earth’s climate system.

Over the 1961 to 2003 period, the average rate
of global mean sea level rise is estimated from tide
gauge data to be 1.8 ± 0.5 mm yr–1.

There is high confidence that
the rate of sea level rise accelerated
between the mid-19th and the
mid-20th centuries based upon tide
gauge and geological data.

During the 20th century, glaciers and ice caps
have experienced widespread mass losses and have
contributed to sea level rise.

The Greenland and Antarctic Ice Sheets taken
together have very likely contributed to the sea level rise
of the past decade. It is very likely that the Greenland
Ice Sheet shrunk from 1993 to 2003, with thickening in
central regions more than offset by increased melting
in coastal regions. Whether the ice sheets have been
growing or shrinking over time scales of longer than a
decade is not well established from observations.

Temperature increases at the top of the permafrost layer of up to 3°C
since the 1980s have been reported. Permafrost warming
has also been observed with variable magnitude in the
Canadian Arctic, Siberia, the Tibetan Plateau and Europe.
The permafrost base is thawing at a rate ranging from
0.04 m yr–1 in Alaska to 0.02 m yr–1 on the Tibetan Plateau.

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

Notice that most of the heat of global warming is going into
the oceans. Only about 2% of the heat is going into surface temperatures.
See Figure TS.15 of the above link for a breakdown.

Also, the following reports month by month surface measurements.

http://www.ncdc.noaa.gov/oa/climate/research/anomalies/index.html

 

[MrGamma]

That is very interesting that most of the heat goes into the oceans. Is that due to the ice melting and perhaps warming the ocean, or is an indication that the warming is coming from other sources, such as the surface or the sea floor? I have always read that water absorbs more CO2 when it is colder, and as it warms it releases the CO2. (I have no practical experience doing so) Perhaps the sea water is absorbing the CO2 instead and thus heating the oceans?

That is incredibly interesting about the Mt.Pinatubo Volcanic Eruptions actually cooling the planet. I have always read that it had the opposite effect and that it was entirely negligible. Perhaps it is? What effect do hydro thermal vents, and underwater eruptions have on the effect of the oceans "salinity".

In particular, what is required to starve an ocean of oxygen? Will more Carbon Dioxide in water reduce it's ability to retain oxygen?

 

[Naty1]

Yes...but that doesn't mean much! During the 1970's the consensus was that an new ice age was "imminent" and was featured,for example, on the cover of Time magazine. (around 1974 or 1975).

It is far more accurate to say that the Earth undegoes warming and cooling cycles due to a wide variety of factors; ice ages, mini ice ages and warming periods are all part of the natural cycle and not fully understood.

 

[BCO]

Yes...but that doesn't mean much! During the 1970's the consensus was that an new ice age was "imminent" and was featured,for example, on the cover of Time magazine. (around 1974 or 1975).

It is far more accurate to say that the Earth undegoes warming and cooling cycles due to a wide variety of factors; ice ages, mini ice ages and warming periods are all part of the natural cycle and not fully understood.

 

[seycyrus]

I don't think that global cooling was ever a "consensus" view in the 70s. This is a very common piece of denialist FUD that gets tossed around all over the Web

Certainly there was no IPCC in 1970 that "declared" a consensus as the current IPCC "declared" one.

There certainly was a lot of talk in the 70s about cooling. Were you alive back then?

 

[Xnn]

Because the oceans are thousands of feet deep, they have a much larger heat capacity than the atmosphere. So, the oceans have been absorbing the bulk of the heat over the years. It's only because they are so large that they have been absorbing most of the heat.

The fact that sea levels are rising from thermal expansion and that overall ice is melting are independent confirmations that the globe is warming. There are also plenty of studies showing that the range of plants and animals are responding to climate change and climate zones shift poleward, so I don't see how anybody can reasonably dispute that there is warming going on.

Anyhow concerning the 1970's, my impression is that there were some people who noticed that a few years were cooler than some previous years and started wondering if perhaps there might be global cooling. The idea was discussed, but never got very far.

However, there are some similarities to today. Some people exclaim that 2005 or 1998 were very warm years and wonder if maybe the warming role of CO2 might be over stated since last year wasn't a record warm year. However, that is short sighted and counter to the consensus science of greenhouse gases.

Never the less, it's obvious that some people are extremely opposed to the whole idea of global warming, but it's not a legitimate scientific objection. Rather it seems more political. That they broke into computers shows me that honesty and integrity mean very little to them. They seem to be trying to make mountains out of mole hills in a fundamentally dishonest type of way.

 

[MrGamma]

OKay, UNderstood. There are three camps? Pro Human Global Warming and Pro Climate Change, and Pro No change.

I am fairly certain we are living on a dynamic planet. I have no doubts about this.

What concerns me are articles like this.

http://www.unep.org/geo/yearbook/yb2009/
What would cause the oceans to deplete of oxygen? Would more carbon dioxide added into water prevent it's ability to retain oxygen?

To my understanding, there are prehistoric records of oxygen deprived oceans existing throughout the geological record and some even claim that it is cyclical. (I am not sold on the concept 100% at the moment)

I am also not sold on the concept that the "dead zones" are caused only by fertilizers. What could have possibly caused it throughout the geological record? Maybe volcanic sulfur? Are volcanoes primarily spitting out Nitrogen in any regards?

However, from a chemical perspective. What causes water to lose it's ability to retain Oxygen. And is there anything in physics which would cause ocean water to absorb more heat than usual, perhaps additional CO2 would cause it to heat up? Or perhaps the release of CO2 would cause it to heat up?

Because the oceans are thousands of feet deep, they have a much larger heat capacity than the atmosphere. So, the oceans have been absorbing the bulk of the heat over the years. It's only because they are so large that they have been absorbing most of the heat.

This is something I have trouble understanding. Shouldn't there be a latentcy between the time the surrounding air heats up the oceans due to greenhouse gases?

If I put a glass of cold water in a room filled with hot air, the water takes it's time absorbing that heat, and it never rises beyond room temperature. Not to my knowledge anyways. Would more CO2 or nitrogen in the Oceans cause it soak up the heat in the atmosphere morseo that the surrounding "air"? Or is the sunlight penetrating more deeply with more force and more heat into the oceans?

What really freaks me out, is that whenever I search for things about underwater volcanoes off the gulf of mexico, that instantly, anti-human-global warming websites pop up. I am obviously not the only one who is questioning it.

 

[Xnn]

What would cause the oceans to deplete of oxygen? Would more carbon dioxide added into water prevent it's ability to retain oxygen?

Going OT here, but the Black Sea is a huge natural dead zone.
It is caused by the bottom water being isolated from mixing with the surface.
Whenever the bottom waters are isolated from the surface there
will be a dead zone since oxygen comes from the surface.
Of course, there are other causes too.

Shouldn't there be a latentcy between the time the surrounding air heats up the oceans due to greenhouse gases?

If I put a glass of cold water in a room filled with hot air, the water takes it's time absorbing that heat, and it never rises beyond room temperature. Not to my knowledge anyways. Would more CO2 or nitrogen in the Oceans cause it soak up the heat in the atmosphere morseo that the surrounding "air"? Or is the sunlight penetrating more deeply with more force and more heat into the oceans?

What really freaks me out, is that whenever I search for things about underwater volcanoes off the gulf of mexico, that instantly, anti-human-global warming websites pop up. I am obviously not the only one who is questioning it.

It does take time for the oceans to warm. However, the oceans have something like a hundred times the mass of the atmosphere. So, if they both warm up by the same delta temperature, then the oceans will have absorbed a hundred times the amount of heat.

An equal rise in temperature does not mean an equal amount of heat energy.
What is more massive (assuming similar specific heat capacity) will absorb more heat.

 

[MrGamma]

Sorry I didn't mean to go off topic. I am just trying to understand the science through the politics.

Going OT here, but the Black Sea is a huge natural dead zone.
It is caused by the bottom water being isolated from mixing with the surface.

So a dead zone can be accomplished through poor circulation and nitrogen (according to msn.com)

It does take time for the oceans to warm. However, the oceans have something like a hundred times the mass of the atmosphere. So, if they both warm up by the same delta temperature, then the oceans will have absorbed a hundred times the amount of heat.

Still not understanding this. But I do understand the temperatures taken in the above refer mostly to the first 700 meters in depth. What about the rest?

I will be honest... I am not 100% certain that human influence is the prime suspect in climate change.

I am more inclined to believe that it's simply a natural phenomenon. Probably to do with the volcanoes, hydro thermal vents, and rift systems which pour lava into the ocean continually. To my knowledge, however, this is also one of the least researched areas of the earth. So I guess perhaps it's easy to "guess" it might be responsible for it.

Shouldn't the sea temperature be cooling if massive ice sheets are melting into the oceans?

 

[Evo]

Still not understanding this. But I do understand the temperatures taken in the above refer mostly to the first 700 meters in depth. What about the rest?

No, actually SST (sea surface temperature) is only the first 1-2 meters of surface water.

A general definition of Sea Surface Temperature (SST) is the water temperature at 1-2 meters below the sea surface

http://www.csc.noaa.gov/products/gulfmex/html/datadesc.htm

 

[sylas]

I'm just wondering if Global Warming is considered a fact within the science community? I'm not talking about man made global warming, just global warming in general whether it be caused by nature or man.

Here's my proposal for a short summary statement on a huge question.

• It is a fact that Earth as a whole warms, or cools for a variety of reasons, and that it has done so throughout its long history.
• It is a fact that the Earth has recently (over the last century) warmed significantly.

There are different estimates for the amount of warming over the last century. They are invariably more than 0.5C and less then 1.0C, and tend to be around 0.7C in total, for the change in average global surface temperatures. The changes tend to be greater over the land than over the ocean and there are substantial regional differences.

Anything "fact" in science is still always open to question in principle. The two facts above are about as solid as science gets for measurements like this. There is of course on going work to get more refined measurements, and more accurate estimates of how warming distributes over time, and over Earth's surface. There is on-going research finding out about changes in the past, and quantifying how current changes compare in the rates of change and extent of change with other episodes of change in the past.

There are also other indicators of temperature than surface temperature which can be used. Surface temperature may be the easiest to measure in the present and also probably the most directly relevant for immediate impact.

Cheers -- sylas

 

[eachus]

Let me establish where I am coming from so you know how much salt to take with my posting. I grew up in Pennsylvania, where you often saw news about coal mines in the newspapers. The words were almost always followed by disaster, and preceded by another. Coal mining is dangerous. Also, go visit Scranton sometime and look at the miles and miles of piles of coal overburden covering what once was fertile farmland.

Whatever the effect of carbon dioxide on the weather, I worry about the effects on humans. We were not evolved as a species the last time carbon dioxide levels were this high. I'd gladly vote money to see if CO2 levels have anything to do with obesity, autism, or what have you. I'm pretty sure that there are some conditions of the elderly that are made worse by higher CO2 levels.

So for me, coal is very bad, and rising CO2 levels are worse. As for global warming? I'm not sure I am against it, even if it is caused by CO2 levels.

Back to the 1970s. You may not remember but there was a major global concern by pilots. The horizon was disappearing. This was considered by pilots to be a severe problem because they relied on the horizon to orient themselves while flying. The disappearing horizon was due to what we would call today nanoparticles of carbon and hydrocarbons suspended in the air, mostly from 707s and other commercial jets. The solution? It had already started. Turbofan (as opposed to turbojet) engines were much more efficient for passenger planes. In a turbofan some of the air taken in by the first fan stage bypasses the compressor and burners. It also results in complete combustion when the bypass air mixes with the air that passed through the compressor and turbine. Airlines all switched to turbofan engines for the fuel savings, and within a few years the horizon returned. I had to wonder if turbofans got extra thrust by burning up unburned particles left by turbojets. I would have expected them to take decades to fall out of the stratosphere.

Anyone who lived in the LA area I am sure remembers a similar phenomena, smog. Diesel engines tuned for maximum efficiency emitted similar particles, as did poorly tuned automobiles. I'm sure we could have had clean air in LA without catalytic converters on automobiles, as long as they got the diesel trucks--and required frequent emissions checks on automobiles. Oh, well. The catalytic converter for everyone approach worked, it just took a lot of research to design automobile engines that worked efficiently with them.

Where am I going with this? I think that given time, the CO2 problem will be corrected like the horizon problem. I can already see that cars five years from now will be at least twice as efficient as today's cars. In part because of worries about high fuel costs, in part due to the improvements in efficiency that come sort of for free when you use electricity instead of a drive shaft. Braking energy is recovered instead of wasted. Even if you have a gasoline engine, it can be tuned to be much more efficient if it runs at just one speed. What about fuel cells? They are coming, but not that fast. And the big thing to sort out is whether they will use hydrogen, methane, methanol, ethanol, or some other fuel. In reality eventually the real fuel is protons (hydrogen ions). The rest is about how you store them, and get them into the fuel cell.

My guess? Methanol, or a methanol/ethanol mix will win out. It is compatible with current delivery systems and also with driver's expectations. The fact that methanol is a much less dangerous fuel in a crash is just a nice side benefit. But all that will take place whether or not a treaty to replace Kyoto is ever signed. It is progress, it is more efficient, and thus saves money. Saving the planet is nice, but doing it at a profit is nicer.

As for base load electrical power, the sooner politicians bite the bulllet and start approving nuclear power plants again, that problem will go away. I could write a whole article on the improvements in nuclear power plant designs and safety, but I won't do that here. The base load problem won't go away. The possibilities are wait until fossil fuel prices go through the roof, build nuclear plants now, or hope for a miracle.

Huh? Green renewable power is nice. It can also potentially provide a lot of swing power, and if done without subsidy, at a sensible price, it won't bust the federal budget. What it can't do is provide reliable power when a blizzard hits the northeast in January. Even if there are lots of wind turbines. ;-) A certain fraction of the electric power generating capacity needs to be reliable in all kinds of weather, and wind and solar are not.

There may be some technology out there that can eventually replace nuclear power without burning coal. But it won't have much of an effect on US or European or Chinese power generation before 2020. And we need to start building new generating plants now, not next decade, or the decade after. We also need to get the Chinese to stop building one new coal plant a week, and do it by example, not by raising the price of coal. (Although that might work. ;-)

 

[russ_watters]

Because the oceans are thousands of feet deep, they have a much larger heat capacity than the atmosphere. So, the oceans have been absorbing the bulk of the heat over the years. It's only because they are so large that they have been absorbing most of the heat.

To quantify that, the mass of a column of air the height of the atmosphere is equal to the mass of a column of water about 10m deep. Since the oceans are about 65% (?) of the surface area of the earth, once you've gone down 15m, you're already dealing with more mass of water than there is air in the atmosphere.

 

[atyy]

An ad-hoc committee of the American Physical Society recently reviewed the that Society's 2007 Statement on Climate Change. The committee's report reads in part:

"There are a number of problems with this statement. The first sentence presents as a fact what is only a surmise. Although the evidence is strong that climate warming has anthropogenic sources, as described above, anthropogenic warming is not a proven fact. Consequently, the wording in the first sentence “are changing the atmosphere” should have been “are probably changing the atmosphere”. In the second paragraph, the first sentence states that the fact of climate warming is incontrovertible, which is true. However, by its context this is easily misread to mean that anthropogenic warming is incontrovertible. The only clue that there are uncertainties in the predictions for the global climate is the phrase “likely to occur” in the second paragraph. This hardly conveys the great uncertainties in analysis displayed in PSB. The paragraph as a whole has an alarmist tone that belies the underlying uncertainties. ...

Despite the uncertainties in detailed predictions, it is the conviction of this committee that the APS would be well advised not to retract its support for policies and actions that are aimed at reduction in the production of greenhouse gasses. The weight of the evidence we have examined points to this as a prudent policy position."

 

[Bored Wombat]

I will be honest... I am not 100% certain that human influence is the prime suspect in climate change.

Well, in terms of the scientific literature, it is the prime suspect for climate change since the middle of last century.

On other time scales there are other prime suspects. The glaciation and interglacial cycles of the last million years and perhaps two are suspected to be primarily from Milankovitch cycles, by a physical mechanism that is not understood. Certainly CO2 provides an important feedback, but does not explain most of the temperature change from the top of an interglacial to the bottom of an ice age.

Specifically the 170 to 270 ppm variation of CO2 should make about 2°C of the about 10°C temperature change.

The bulk of it, AFAIK is ice-albedo feedback.

I am more inclined to believe that it's simply a natural phenomenon. Probably to do with the volcanoes, hydro thermal vents, and rift systems which pour lava into the ocean continually. To my knowledge, however, this is also one of the least researched areas of the earth. So I guess perhaps it's easy to "guess" it might be responsible for it.

Volcanic forcing (being aerosol forcing) is well considered. Geothermal heat is understood to be a negligible source of heat to the atmosphere and ocean. It's pretty much all the sun.

Shouldn't the sea temperature be cooling if massive ice sheets are melting into the oceans?

The last time I did the figures, the radiative imbalance due to the enhanced greenhouse effect is more than the latent heat of fusion of the melting sea ice.

 

[ZacharyFino]

its weird, when i was younger i always thought that the planet was getting warmer and warmer because its covered in billions of buildings all using electricity and cars people etc. so much going on on the surface it just seems if you isolate it as a system there is a large amount of energy wrapped around the planet, then in the 9th grade global warming by CO2 gasses was introduced to me. I've been skeptical the whole time, i accept the physics of greenhouse gases but it doesn't seem apparent to me that the greatest source of global warming is CO2 and that it is an immediate problem.

 

[andrewBR]

I don't guess that the global warming is a fact!
Tha planet is very strange, but this the result of the millions years of evollution
For me, this is normal, the planet needs change!

 

[sylas]

its weird, when i was younger i always thought that the planet was getting warmer and warmer because its covered in billions of buildings all using electricity and cars people etc. so much going on on the surface it just seems if you isolate it as a system there is a large amount of energy wrapped around the planet, then in the 9th grade global warming by CO2 gasses was introduced to me. I've been skeptical the whole time, i accept the physics of greenhouse gases but it doesn't seem apparent to me that the greatest source of global warming is CO2 and that it is an immediate problem.

The original source of warming for the Earth is the Sun. Nothing else even comes close to making the slightest difference as an energy source. All climate impacts come from changing in some way the flow of energy that comes from the Sun.

The Sun itself is remarkably constant; but the way that energy flows through the Earth is not. Earth radiates all the energy it receives from the Sun. This is called "energy balance". There can be a short term imbalance with energy actually being stored or released from the Earth, but this cannot last. The amount of energy is too large.

What makes a difference for temperature is basically two things.

• Albedo. How much solar energy gets reflected. Reflected energy does not contribute to heating.
• Emissivity. This is a measure of how efficient the Earth is at radiating heat. This is where carbon dioxide makes a difference. It makes it a bit harder for the thermal energy radiated from the Earth to get out into space; and that means you end up with higher temperatures just to keep radiating the same amount of energy.

To accept the physics of greenhouse gases MEANS to recognize a strong effect on temperature from just this effect. The physics involved implies higher temperatures when you have more greenhouse gases.

Cheers -- sylas

 

[eachus]

To accept the physics of greenhouse gases MEANS to recognize a strong effect on temperature from just this effect. The physics involved implies higher temperatures when you have more greenhouse gases.

Yep, the physics is easy--if you have growing levels of greenhouse gases (GHG) in the atmosphere. However, the primary GHG is water vapor. If the amount of water vapor was constant, then it would be easy to make working models of the atmosphere that include radiative forcing from CO2. But it is not that simple by any means. Clouds increase albedo, and thus reflect more sunlight, but they also trap heat, preventing radiative cooling from the ground or ocean under the clouds. So do clouds cause warming or cooling? Both, and sometimes at the same time. :-(

Remember that I am in favor of reducing CO2 levels. I just don't think that radiative forcing from CO2 is real.

There is not much research money these days for studying the Gaia hypothesis, that natural feedback paths make Earth's climate self regulating. But given that the solar constant has not been constant when looked at over billion year timescales, something has kept Earth from being an iceball or a Venus-like hothouse.

To be perfectly fair, current research seems to indicate that the Earth did go through an iceball (or slushball) phase several times over half a billion years ago. But it didn't stay locked in that mode. There are scientists trying to fit models that make CO2 responsible for leaving the icehouse mode. I happen to favor mountain building as the solution. And the long north-south mountain chain along the Pacific edge of the Americas as why the recent (in geological terms) Ice Ages didn't become Iceball Ages.

 

[sylas]

Remember that I am in favor of reducing CO2 levels. I just don't think that radiative forcing from CO2 is real.

My primary interest in this is from a long time interest in science education and issues where science gets misunderstood in the public sphere. What we ought to do policy wise is a social issue, which is best informed after we understand the best available relevant science.

The radiative forcing of CO₂ is one of the simplest and most elementary aspects of the whole science of climate. The physics of it has been known since the nineteenth century, and it can be quantified quite accurately with calculations from a couple of decades ago. (The full calculation is pretty arduous and requires a lot of computer time to integrate over the vertical atmosphere profile and over the electromagnetic spectrum.)

The result is 5.35 W/m² of forcing per natural log of CO₂, accurate to 10% or so. The major reference for this is

• Myhre et al., (1998) http://www.agu.org/pubs/crossref/1998/98GL01908.shtml, Geophysical Research Letters, Vol 25, No. 14, pp 2715-2718.

Note that the forcing is not in terms of temperature, but energy flux. This is what forcing means.

The next obvious question, of course, is what consequences the additional energy flux has for temperature. It will increase temperature of course; but how much? This is the source of the real uncertainties and open questions in climate science; the complex nature of the Earth response.

As temperatures rise, you get increasing specific humidity, and this (as you point out!) is the major greenhouse gas on Earth. This increase in humidity is measured, and it works as a strong positive feedback, basically amplifying the response to ANY forcing.

The other major effect is changes to weather patterns, and cloud in particular. This (as you point out) is very complicated. Most research indicates that the net effect of changing cloud in a situation of increasing temperatures is another positive feedback; although its magnitude is one of the greatest sources of uncertainty and even its sign is subject to question; under certain conditions it will be a negative (moderating) feedback.

There is not much research money these days for studying the Gaia hypothesis, that natural feedback paths make Earth's climate self regulating. But given that the solar constant has not been constant when looked at over billion year timescales, something has kept Earth from being an iceball or a Venus-like hothouse.

You don't need a Gaia hypothesis for that, or self-regulation. Even with mostly positive (amplifying) feedbacks you tend to get reasonable long term stability. There's been a lot of very significant climate change over that period. For example: consider the cycle of ice ages over the last 2.8 million years (Quaternary period). Those are very large climate shifts, and they are driven by very small changes in Earth's orbit, we think. That requires some strong positive amplifying feedbacks to give such large swings in climate.

The only reason the swings don't go to a slushball or to a Venus like hothouse is that the feedbacks are still subcritical, so the response to a bounded forcing is itself bounded. Trying to marry that with the idea of "self-regulation" is rather odd.

Be that as it may, there's plenty of scope for looking at longer term feedback processes.

To be perfectly fair, current research seems to indicate that the Earth did go through an iceball (or slushball) phase several times over half a billion years ago. But it didn't stay locked in that mode. There are scientists trying to fit models that make CO2 responsible for leaving the icehouse mode. I happen to favor mountain building as the solution. And the long north-south mountain chain along the Pacific edge of the Americas as why the recent (in geological terms) Ice Ages didn't become Iceball Ages.

That is a very strange idea. You don't need any particular "reason" why recent Ice Ages don't go to slush balls. The only way to get the extreme slush ball is a runaway positive feedback. You don't need anything special to prevent this; and in particular you could probably have the Americas flat as a pancake without causing slushballs from the small forcings involved in the ice ages.

Ironically, the major effects of Earth's current arrangement of continents is to reduce the stability of climate, and contribute to the case where we've been having these large swings in climate in and out of Ice Ages with what are comparatively small orbital forcings. That is, these are not moderating influences; but actively help bring about large climate swings.

See, for example, Shifting Continents and Climates, a background article at Oceanus (23 Feb 2004) at the Woods Hole Oceanographic Institute.

Cheers -- sylas

 

[ViewsofMars]

Hi :)

I used to live on an island, and it was there I fell in love with the whales, dolphins and porpoises. I don’t want them to suffer. I’m especially fond of dolphins because they are super intelligent and playful creatures. I found this article which made me sad.

The Impact of a Changing Climate on Whales, Dolphins and Porpoises by Wendy Elliott, WWF Global Species Programme, and edited by Mark Simmonds, Whale and Dolphin Conservation Society (WDCS).

http://www.wdcs.org/submissions_bin/whales_hot_water.pdf

On a happier note, a friend of mine gave me a present. It was a huge gourd that had small (three inch) strokes of blue and white little whales on it and was painted by a killer whale. I have a photograph of the whale painting the gourd! It's awesome. Everytime I look at it I think of the beauty that is alive and breathing, which brings me joy. There was a "Certificate of Authenticity" that came along with the gourd. It reads, "Shouka, Killer Whale (Orcinus orca) is one of Six Flags Discovery Kingdom's most enthusiastic painters. Painting is one of the many fun activities Shouka enjoys with her trainers between shows. She painted her first gourd in honor of the 2nd annual Mare Faire. She loves a lot of attention from her trainers, dolphin companions, and other human friends. She can often be heard outside Shouka Stadium when she is vocalizing with excitement during a variety of activities such as painting, mimicking her trainers and eating ice."

 

[eachus]

The radiative forcing of CO₂ is one of the simplest and most elementary aspects of the whole science of climate. The physics of it has been known since the nineteenth century, and it can be quantified quite accurately with calculations from a couple of decades ago. (The full calculation is pretty arduous and requires a lot of computer time to integrate over the vertical atmosphere profile and over the electromagnetic spectrum.)

The result is 5.35 W/m² of forcing per natural log of CO₂, accurate to 10% or so. The major reference for this is

• Myhre et al., (1998) http://www.agu.org/pubs/crossref/1998/98GL01908.shtml, Geophysical Research Letters, Vol 25, No. 14, pp 2715-2718.

Maybe I didn't spell it out well enough. So I'll let H. L. Mencken try: "For every complex problem, there is a solution that is simple, neat, and wrong." In this case the assumption that blows up is that the CO2 is evenly distributed throughout the atmosphere. We now know that assumption is wrong in two dimensions. CO2 is heavier than air, so anthropocentric CO2 tends to stay in the lower atmosphere, where it does not contribute to radiative forcing or global warming. (CO2 from volcanoes is injected into the upper atmosphere, and tends to stay there. But that is a different issue.)

The other simplifying assumption that fails is that anthropocentric CO2 is distributed evenly in latitude. NASA has some nice animations which show just how wrong this is--there are two belts of anthropocentric CO2 in the mid-latitudes in both hemispheres, while the CO2 concentration in higher latitudes and at the equator is much lower.

Put it all together, and anthropocentric CO2 doesn't do much forcing, if any. But remember what I said, that I am very much in favor of reducing CO2 emissions because the current levels are already killing people--but elderly people and people with asthma, not by global warming.

A good test of how well someone understands the issues is their attitude towards nuclear power. Nuclear power is the only remotely reasonable replacement for base load coal plants today. You are allowed to be opposed to liquid metal fast breeder reactors (LMFBRs) but that is a detail. I don't know of anyone who still wants to build LMFBRs to close the nuclear fuel cycle. Today, gas cooled and molten salt breeders are a much safer, and actually less expensive alternative.

 

[sylas]

Maybe I didn't spell it out well enough.

You spelt it out just fine. It is not that I fail to understand you; it is that we disagree. Put more bluntly; you are incorrect, and spelling it out in more detail only underlines the problems.

In this case the assumption that blows up is that the CO2 is evenly distributed throughout the atmosphere. We now know that assumption is wrong in two dimensions. CO2 is heavier than air, so anthropocentric CO2 tends to stay in the lower atmosphere, where it does not contribute to radiative forcing or global warming. (CO2 from volcanoes is injected into the upper atmosphere, and tends to stay there. But that is a different issue.)

Variation in CO₂ levels is not enough to make a significant difference to the forcing in different parts of the Earth. The extra weight is irrelevant; the various gases are well mixed in the troposphere and do not separate out by weight until you get above the tropopause. The global warming impact of greenhouse gases is due to their existence below the tropopause, because their crucial role is to leave the bulk of atmospheric thermal emissions from the tropospause, which is much colder than the surface.

A recent thread has been started on improved details in CO₂ measurements from the NASA AIRS project. See the thread [thread=363850]AIRS and Atmospheric Carbon Dioxide[/thread]. The measurements shown are for mid-troposphere, and the variation is only a few percent -- as expected for well mixed gases in the turbulent troposphere. The variation is far less that the steady increase occurring at all latitudes and all altitudes as atmospheric CO₂ levels continue to rise.

It is a requirement of this forum that controversial claims be backed up by suitable scientific references. In this case, your assertions about a separation of CO₂ by weight, and of a lack of any contribution to forcing for anthropogenic CO₂ is in conflict with very elementary atmospheric physics.

The other simplifying assumption that fails is that anthropocentric CO2 is distributed evenly in latitude. NASA has some nice animations which show just how wrong this is--there are two belts of anthropocentric CO2 in the mid-latitudes in both hemispheres, while the CO2 concentration in higher latitudes and at the equator is much lower.

By "much" you mean about 2%? Did you even read that research?

Put it all together, and anthropocentric CO2 doesn't do much forcing, if any. But remember what I said, that I am very much in favor of reducing CO2 emissions because the current levels are already killing people--but elderly people and people with asthma, not by global warming.

CO₂ levels are pretty much irrelevant for direct impact on health, at least at the levels seen in the normal atmosphere. The effect of atmospheric CO₂ on asthma is negligible. Again, you should support claims like this.

I have quoted the references for forcing of 5.35 W/m² per natural log CO₂. This is a well established forcing, not in any credible doubt. Your claims about variation in CO₂ levels don't appear to appreciate how small these variations actually are. Anthropgenic CO₂ mixes all through the atmosphere, and by basic thermodynamics it necessarily gives a substantial radiative forcing. The forcing due to CO₂ increases since pre-industrial times is about 1.7 W/m², corresponding to a rise from 280ppm to 385ppm, and the source of this increase is anthropogenic, as established by the Suess effect and also by simple bookkeeping with the magnitude of fluxes involved.

The impacts or social issues or policy issues are not on topic in this thread. The question is simply about getting the science of climate right. Is global warming a fact? Yes it is; and so also is the significance of CO₂ as a major contributing factor to increasing temperatures.

What remains uncertain is the magnitude of climate response to various forcings (sensitivity), the associated patterns of climate change as the globe heats up, and also the contribution of various other forcings, both non-greenhouse forcings, and greenhouse forcings from other gases.

Cheers -- sylas

 

[Xnn]

eachus;

Global warming due human emission of CO2 is a fact. However, the rate of change is so slow (0.02C/year) that it is difficult to measure and easy to dismiss. Even over 10 years, 0.2C is a small change.

On a typical day, temperatures vary by 10C between day and night.
While from one day to the next, 3 or 4 C is not unusual.

So, even though the science of global warming from CO2 is well understood and http://www.ipcc.ch/publications_and_data/ar4/wg1/en/contents.html" , we will continue to find people that are quick to reject it without taking the time to understand it.

Some of the opposition is due to a lack of knowledge, but others are driven by fear and political motives.

 

[Bill Illis]

Anyone ever put Myhre's forcing estimates into the Stefan-Boltzmann equations.

If the total forcing increase from GHGs is 1.7 W/m2, the Stefan-Boltzmann equations predict very little temperature change from an increase this small.

Surface TempK Today = (390 W/m2/5.67E-08)^.25 = 287.98K = 15.0C

Surface TempK Pre-Ind = (388.3 W/m2/5.67E-08)^.25 = 287.66K = 14.7C

So either Myhre's estimates are not really the traditional watts/metre^2 measure we use normally or the Stefan-Boltzmann equations aren't even being used.

 

[ViewsofMars]

The American Association for the Advancement of Science has the “Science Insider” with articles pertaining to this discussion. I think it’s worthy of a review. Thanks.

http://blogs.sciencemag.org/cgi-bin/mt/mt-search.cgi?tag=Copenhagen&blog_id=9&IncludeBlogs=9

 

[sylas]

Anyone ever put Myhre's forcing estimates into the Stefan-Boltzmann equations.

Yes, they have. What the Stefan-Bolzmann equations give you is called "non-feedback response". But note that the forcing calculation by Myhre is not based on Stefan-Bolztman. It is based on radiative transfers up and down a transparent atmosphere. The calculation you are doing is a kind of check to see how the known forcing of CO₂ matches up with the observed changes in temperature.

The difference with the real climate on Earth is that as temperature increases, so also do other aspects that bear upon energy balance. Ice melts (increasing albedo), humidity increases (more greenhouse, but less lapse rate) cloud changes (altering both greenhouse and albedo in complex ways); plus also changes in vegetation and land cover.

All this becomes feedback, either positive or negative, which bears upon "climate sensitivity" to either amplify or damp the base non-feedback response.

I mentioned this in my earlier post, as an aspect of climate that is NOT well known. The base non-feedback response is pretty well constrained, but it does not suffice to let you infer the temperature impact.

If the total forcing increase from GHGs is 1.7 W/m2, the Stefan-Boltzmann equations predict very little temperature change from an increase this small.

Surface TempK Today = (390 W/m2/5.67E-08)^.25 = 287.98K = 15.0C

Surface TempK Pre-Ind = (388.3 W/m2/5.67E-08)^.25 = 287.66K = 14.7C

So either Myhre's estimates are not really the traditional watts/metre^2 measure we use normally or the Stefan-Boltzmann equations aren't even being used.

There are several omissions in your application of Stefan-Boltzmann, even ignoring the effects of all the feedback processes. Most importantly, you are mixing up a surface temperature change with a forcing that is defined with respect to the top of the atmosphere.

Here is a better way of doing it. The Earth is not a black body emitter. You must consider both albedo and emissivity.

The Earth has an albedo of about 0.3, which means that about 30% of the solar input is reflected, and does not give any heating. Also, the radiation into space from the Earth corresponds to an effective temperature of about 255K. This is because of the greenhouse effect, which gives Earth an effective emissivity. Surface temperature is about 288K, because of the additional blanketing effect of the atmosphere.

You get into the right ball park by using a grey-body approximation relating surface temperature to the absorbed solar energy. For a grey-body, the Stephan-Boltzmann relation is

Q = \sigma \epsilon T^4​

Q is the thermal emission flux from the top of the atmosphere, and ε is an effective emissivity. T is the surface temperature.

The solar constant is about 343 W/m² over the surface of the planet. 30% of this is reflected, leaving 240 W/m² energy absorbed. This is what Earth emits as thermal radiation; it is the value for Q. T is the surface temperature, about 288K.

The value for ε is about 0.6; but in fact we can cancel it as follows.

\frac{dQ}{dT} = 4 \sigma \epsilon T^3 = 4Q/T​

The rate of change of energy emitted with temperature is about 4 * 240 / 288 = 3.3 W/m²/K. This is a non-feedback response. For every 3.3 W/m² of forcing (change in Q) we should get about a degree of temperature change -- ignoring feedbacks.

The 1.7 W/m² forcing corresponds to a bit over half a degree.

You obtain a slightly smaller value because you are using Stephan-Boltzmann at the surface, with Q=390 as the emission of radiation from the surface. But that's the wrong comparison for a forcing, which by definition is the change in energy balance at the top of the atmosphere. The method with a non-unit emissivity will give you a closer value for the proper application of Stefan-Boltzman to a forcing. There are in the literature more detailed calculations considering the emissivity of the atmosphere and the fact that the Earth is not a uniform sphere. The value obtained is around 3.2 W/m²/K; close to the simple approximation I used above.

There are a number of important provisos with this number.

• It ignores all feedbacks. This is one of the major open questions in climate research. Most of the available evidence indicates a net positive feedback, to give a substantial amplification of the base response. A small minority of researchers propose a zero or negative feedback, but over all they have not been made a good scientific case for this, and nearly all estimates suggest that the base response is increased by a factor of around 2 to 4 times.
• This is an equilibrium response. Since it takes a long time for the ocean to heat up in response to a new forcing, you don't get all this temperature increase realized at once. Research indicates at present a steady flux of energy flowing into the ocean. This represents a forcing that is not yet realized as a surface temperature increase.
• It ignores all other forcings; there's more than CO₂ involved.

As it turns out, these additional considerations mostly cancel out. The effect of time delay with heating of the ocean works in the short term rather like a negative feedback, and so the observed amplification short term is smaller than than full equilibrium response. The other additional forcings are both positive and negative, and of comparable magnitudes each way.

The net effect is that the base response is not that far off what we should experience; generally estimated to be a small amplification over base response.

So... a naive application of Stefan-Boltzman to CO₂ levels alone gives about half a degree of heating. And the actual temperature rise we have observed is in a similar ballpark... around 0.7 degrees.

For more discussion in other threads:

• Feedback is now being discussed in thread [thread=360877]The AGW climate feedback discussion[/thread].
• Base response is discussed, with references, in [post=2199572]msg #69[/post] of thread "Physics of Global Warming", and [post=2225918]msg #47[/post] of "Ocean heat storage". The values given for base response from the literature are about 3.2 W/m²/K.

Cheers -- sylas

 

[Xnn]

Bill; That's a good point.

Although I apply the Stefan-Boltzmann differantly, I still get a similar answer; 0.5C.

Basic Stefan-Boltzmann equation:

Temp (K) = [2*TSI*emissitivity*(1-albedo)/(4*5.67*x10^-8)]^(0.25)

TSI: Total Solar Irradiance - Watts/m^2
emissitivity; nominally 0.81 - unitless
albedo; nominally 0.3 - unitless

The 1.7 watt/m^2 forcing is applied to what could be considered to be the net incoming radiation term:

TSI*(1-albedo)/4

net result 0.5C of warming since pre-industrial times due to human influence and including solar changes.

The IPCC gives a global mean radiative forcing value since pre-industrial times of 1.6 watts/m2 with a range of 0.6 to 2.4. This includes all greenhouse gases, land use, black carbon, aerosols, contrails and solar irradiance.

What's missing are the feedbacks from water vapor and snow/ice melting albedo changes. So, feedbacks have made the observed warming greater than that from the underlying inital changes.

 

[Bill Illis]

I guess I have a number of issues with the standard explanations for the physics of global warming (and thanks to sylas and Xnn for indulging me here):

First, the Stefan-Boltzmann equations are the fundamental equations governing radiation physics and temperature. I really think that global warming theory needs to be consistent in some form with these proven and successful equations.

Second, the Stefan-Boltzmann equations are logarithmic. The surface of the Earth needs to add 5.5 W/m2 to go up by 1.0K but the Sun needs to add 50,000 W/m2 to increase its temperature by 1.0K. We can't use averages covering many different radiation levels in these calculations. It must be done on each individual extra watt, one at a time - the differential rather than the average.

Third, there are four different levels of the atmosphere which are emitting at 240 W/m2. Traditionally, the tropopause is defined as the level where the Earth is in equilibrium with the Solar forcing - the first level where that occurs is about 4 kms up - lower than the top of Mount Everest and lower than the definition of the tropopause.

http://www.fas.org/irp/imint/docs/rst/Sect14/FIG01_019.jpg

Fourth, all the effective action of the greenhouse effect operates below this 4 km level. We use the term "Emissivity or even the Lapse Rate" but isn't this really just the time delay it takes for an Infra-Red photon from the surface to random walk/bounce around the atmosphere and the surface before it reaches the 4 km level and eventually escapes back into space. The average time a photon from the Sun spends in the Earth system is only 18 hours (some make it to the deep ocean and spends a thousand years in the Earth system while the majority of the energy represented by photons from the Sun escapes to space overnight after bouncing around a million individual atmosphere molecules. For every 240 W/m2 coming in from the Sun, an extra 150 w/m2 is time-delayed/accumulated near the surface to provide the Greenhouse Effect and keep the surface 33K warmer than the equilibrium temperature at 4 kms high.

Fifth, since these issues are so complicated and prone to error, why do we not look at the empirical evidence of the paleoclimate to provide an independent verification of the theory. Since the issues are so theoritical, we should go back to ground and see what has really happened in the climate per doubling of CO2. The actual/estimated temperature and CO2 history of the climate does not verify the 3.0C per doubling estimate. The paleoclimate is only consistent with 1.0C to 1.5C per doubling.

Maybe I am way off base here, but these issues are not addressed in the standard explanation. It only takes a 25% error in the estimates from the standard explanation to make a huge difference in the global warming per doubling estimate.