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Wax
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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.
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.
Naty1 said: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 said: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
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.
MrGamma said:What would cause the oceans to deplete of oxygen? Would more carbon dioxide added into water prevent it's ability to retain oxygen?
MrGamma said: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 said: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.
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.
No, actually SST (sea surface temperature) is only the first 1-2 meters of surface water.MrGamma said: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?
A general definition of Sea Surface Temperature (SST) is the water temperature at 1-2 meters below the sea surface
Wax said: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.
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.Xnn said: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.
MrGamma said:I will be honest... I am not 100% certain that human influence is the prime suspect in climate change.
MrGamma said: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.
MrGamma said:Shouldn't the sea temperature be cooling if massive ice sheets are melting into the oceans?
ZacharyFino said: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.
sylas said: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.
eachus said: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 said: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.
eachus said:Maybe I didn't spell it out well enough.
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.
Bill Illis said: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.
Comput Biol Chem. 2009 Dec;33(6):415-20. Epub 2009 Oct 2.
Modelling effects of geoengineering options in response to climate change and global warming: implications for coral reefs.
Crabbe MJ.
LIRANS Institute for Research in the Applied Natural Sciences, Faculty of Creative Arts, Technologies and Science, University of Bedfordshire, Park Square, Luton LU1 3JU, UK. james.crabbe@beds.ac.uk
Climate change will have serious effects on the planet and on its ecosystems. Currently, mitigation efforts are proving ineffectual in reducing anthropogenic CO2 emissions. Coral reefs are the most sensitive ecosystems on the planet to climate change, and here we review modelling a number of geoengineering options, and their potential influence on coral reefs. There are two categories of geoengineering, shortwave solar radiation management and longwave carbon dioxide removal. The first set of techniques only reduce some, but not all, effects of climate change, while possibly creating other problems. They also do not affect CO2 levels and therefore fail to address the wider effects of rising CO2, including ocean acidification, important for coral reefs. Solar radiation is important to coral growth and survival, and solar radiation management is not in general appropriate for this ecosystem. Longwave carbon dioxide removal techniques address the root cause of climate change, rising CO2 concentrations, they have relatively low uncertainties and risks. They are worthy of further research and potential implementation, particularly carbon capture and storage, biochar, and afforestation methods, alongside increased mitigation of atmospheric CO2 concentrations.
PMID: 19850527 [PubMed - in process]
http://www.ncbi.nlm.nih.gov/sites/e...ez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
J Air Waste Manag Assoc. 2009 Oct;59(10):1194-211.
Global climate change and the mitigation challenge.
Princiotta F.
Air Pollution Prevention and Control Division, National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA. Princiotta.frank@epa.gov
Anthropogenic emissions of greenhouse gases, especially carbon dioxide (CO2), have led to increasing atmospheric concentrations, very likely the primary cause of the 0.8 degrees C warming the Earth has experienced since the Industrial Revolution. With industrial activity and population expected to increase for the rest of the century, large increases in greenhouse gas emissions are projected, with substantial global additional warming predicted. This paper examines forces driving CO2 emissions, a concise sector-by-sector summary of mitigation options, and research and development (R&D) priorities. To constrain warming to below approximately 2.5 degrees C in 2100, the recent annual 3% CO2 emission growth rate needs to transform rapidly to an annual decrease rate of from 1 to 3% for decades. Furthermore, the current generation of energy generation and end-use technologies are capable of achieving less than half of the emission reduction needed for such a major mitigation program. New technologies will have to be developed and deployed at a rapid rate, especially for the key power generation and transportation sectors. Current energy technology research, development, demonstration, and deployment (RDD&D) programs fall far short of what is required.
PMID: 19842327 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/sites/e...ez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
Title: The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks
Authors:
Bates, N. R.; Mathis, J. T.
Affiliation:
AA(Bermuda Institute of Ocean Sciences, Ferry Reach, Bermuda nick.bates@bios.edu), AB(School of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, Alaska, USA)
Publication:
Biogeosciences, Volume 6, Issue 11, 2009, pp.2433-2459 (COPERNICUS Homepage)
Publication Date:
11/2009
Origin:
COPERNICUS
Bibliographic Code:
2009BGeo...6.2433B
Abstract
At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2) on the order of ‑66 to ‑199 Tg C year‑1 (1012 g C), contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3) mineral saturation states (Ω) of seawater while seasonal phytoplankton primary production (PP) mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems
http://adsabs.harvard.edu/abs/2009BGeo...6.2433B
Bill Illis said: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.
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.
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.
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.
Bill Illis said: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.
Bill Illis said: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.
Xnn said:Sylas provided a good response, but I'll like to add the the middle plicone is also being studied. The conclusions are that there is more warming found during that time than can be explained with the standard 2-4.5C/CO2 doubling. This is due to changes in vegetation and melting of Greenland and Antarctica; feedbacks which have not been taken into account by most climate models.
http://www.giss.nasa.gov/research/features/199704_pliocene/page2.html