Global warming less extreme than feared?
Policymakers are attempting to contain global warming at less than 2°C. New estimates from a Norwegian project on climate calculations indicate this target may be more attainable than many experts have feared.
Internationally renowned climate researcher Caroline Leck of Stockholm University has evaluated the Norwegian project and is enthusiastic.
“These results are truly sensational,” says Dr Leck. “If confirmed by other studies, this could have far-reaching impacts on efforts to achieve the political targets for climate.”
Temperature rise is levelling off
After Earth’s mean surface temperature climbed sharply through the 1990s, the increase has levelled off nearly completely at its 2000 level. Ocean warming also appears to have stabilised somewhat, despite the fact that CO2 emissions and other anthropogenic factors thought to contribute to global warming are still on the rise.
It is the focus on this post-2000 trend that sets the Norwegian researchers’ calculations on global warming apart.
Sensitive to greenhouse gases
Climate sensitivity is a measure of how much the global mean temperature is expected to rise if we continue increasing our emissions of greenhouse gases into the atmosphere.
CO2 is the primary greenhouse gas emitted by human activity. A simple way to measure climate sensitivity is to calculate how much the mean air temperature will rise if we were to double the level of overall CO2 emissions compared to the world’s pre-industrialised level around the year 1750.
If we continue to emit greenhouse gases at our current rate, we risk doubling that atmospheric CO2 level in roughly 2050.
Mutual influences
A number of factors affect the formation of climate development. The complexity of the climate system is further compounded by a phenomenon known as feedback mechanisms, i.e. how factors such as clouds, evaporation, snow and ice mutually affect one another.
Uncertainties about the overall results of feedback mechanisms make it very difficult to predict just how much of the rise in Earth’s mean surface temperature is due to manmade emissions. According to the Intergovernmental Panel on Climate Change (IPCC) the climate sensitivity to doubled atmospheric CO2 levels is probably between 2°C and 4.5°C, with the most probable being 3°C of warming.
In the Norwegian project, however, researchers have arrived at an estimate of 1.9°C as the most likely level of warming.
Manmade climate forcing
“In our project we have worked on finding out the overall effect of all known feedback mechanisms,” says project manager Terje Berntsen, who is a professor at the University of Oslo’s Department of Geosciences and a senior research fellow at the Center for International Climate and Environmental Research – Oslo (CICERO). The project has received funding from the Research Council of Norway’s Large-scale Programme on Climate Change and its Impacts in Norway (NORKLIMA).
“We used a method that enables us to view the entire earth as one giant ‘laboratory’ where humankind has been conducting a collective experiment through our emissions of greenhouse gases and particulates, deforestation, and other activities that affect climate.”
For their analysis, Professor Berntsen and his colleagues entered all the factors contributing to human-induced climate forcings since 1750 into their model. In addition, they entered fluctuations in climate caused by natural factors such as volcanic eruptions and solar activity. They also entered measurements of temperatures taken in the air, on ground, and in the oceans.
The researchers used a single climate model that repeated calculations millions of times in order to form a basis for statistical analysis. Highly advanced calculations based on Bayesian statistics were carried out by statisticians at the Norwegian Computing Center.
2000 figures make the difference
When the researchers at CICERO and the Norwegian Computing Center applied their model and statistics to analyse temperature readings from the air and ocean for the period ending in 2000, they found that climate sensitivity to a doubling of atmospheric CO2 concentration will most likely be 3.7°C, which is somewhat higher than the IPCC prognosis.
But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a “mere” 1.9°C.
Professor Berntsen says this temperature increase will first be upon us only after we reach the doubled level of CO2 concentration (compared to 1750) and maintain that level for an extended time, because the oceans delay the effect by several decades.
The figure of 1.9°C as a prediction of global warming from a doubling of atmospheric CO2 concentration is an average. When researchers instead calculate a probability interval of what will occur, including observations and data up to 2010, they determine with 90% probability that global warming from a doubling of CO2 concentration would lie between 1.2°C and 2.9°C.
This maximum of 2.9°C global warming is substantially lower than many previous calculations have estimated. Thus, when the researchers factor in the observations of temperature trends from 2000 to 2010, they significantly reduce the probability of our experiencing the most dramatic climate change forecast up to now.
Professor Berntsen explains the changed predictions:
“The Earth’s mean temperature rose sharply during the 1990s. This may have caused us to overestimate climate sensitivity.
“We are most likely witnessing natural fluctuations in the climate system – changes that can occur over several decades – and which are coming on top of a long-term warming. The natural changes resulted in a rapid global temperature rise in the 1990s, whereas the natural variations between 2000 and 2010 may have resulted in the levelling off we are observing now.”
Climate issues must be dealt with
Terje Berntsen emphasises that his project’s findings must not be construed as an excuse for complacency in addressing human-induced global warming. The results do indicate, however, that it may be more within our reach to achieve global climate targets than previously thought.
Regardless, the fight cannot be won without implementing substantial climate measures within the next few years.
Sulphate particulates
The project’s researchers may have shed new light on another factor: the effects of sulphur-containing atmospheric particulates.
Burning coal is the main way that humans continue to add to the vast amounts of tiny sulphate particulates in the atmosphere. These particulates can act as condensation nuclei for cloud formation, cooling the climate indirectly by causing more cloud cover, scientists believe. According to this reasoning, if Europe, the US and potentially China reduce their particulate emissions in the coming years as planned, it should actually contribute to more global warming.
But the findings of the Norwegian project indicate that particulate emissions probably have less of an impact on climate through indirect cooling effects than previously thought.
So the good news is that even if we do manage to cut emissions of sulphate particulates in the coming years, global warming will probably be less extreme than feared.
| About the project |
| Geophysicists at the research institute CICERO collaborated with statisticians at the Norwegian Computing Center on a novel approach to global climate calculations in the project “Constraining total feedback in the climate system by observations and models”. The project received funding from the Research Council of Norway’s NORKLIMA programme.The researchers succeeded in reducing uncertainty around the climatic effects of feedback mechanisms, and their findings indicate a lowered estimate of probable global temperature increase as a result of human-induced emissions of greenhouse gases.The project researchers were able to carry out their calculations thanks to the free use of the high-performance computing facility in Oslo under the Norwegian Metacenter for Computational Science (Notur). The research project is a prime example of how collaboration across subject fields can generate surprising new findings. |
- Written by:
- Bård Amundsen/Else Lie. Translation: Darren McKellep/Carol B. Eckmann
- h/t to Andrew Montford via Leo Hickman
RACookPE1978 says, January 26, 2013 at 6:59 pm: “Then they minimize radiation losses to the wall with that reflective coating on the walls. …”
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I perfectly understand the idea behind the reflective coating in a thermos, and it is not different from the idea about “greenhouse gases” reducing radiation losses etc., but the problem is that this idea is apparently wrong.
As I said, coffee/surface radiate thus getting colder. Then the radiation meets the reflective coating/”greenhouse gases” and is sent back, wonderful. Now it is back radiation. The question is: does it affect the temperature of the source? The answer given by the Wood experiment (1909) is “no” (or negligible).
Eventually, we will enter the true negative territory. CO2’s radiative powers will be revealed.
@Brian H Careful, you could be right,the correlation is leaning that way and we know what the IPCC can do with correlation
greg house;
The question is: does it affect the temperature of the source? The answer given by the Wood experiment (1909) is “no” (or negligible).
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Every day, all over the world, tens of thousands of engineers design everything from blankets to nuclear reactors using the precise physics that greg house insists are impossible. Yet the things they build work as designed. Odd that, Must be some kind of effing fluke that happens over and over again where thousands of other factors accidentally cancel out the errors in the design so that they work precisely as designed despite the impossible physics. These thousands of errors per product times millions of products means that greg house is right but the engineers made trillions upon trillions of mistakes that all cancel out the bad physics.
Or maybe they got the physics right. Nah. Impossible.
Wait, do we trust the science today or not? I thought we didn’t trust those scientists. I’m confused.
It can’t be said too often that climate models are merely contrivances meant to project a future warming trend indefinitely. They can do no else. There is nothing that verifies their product and in fact all observations refute the GCM’s. Those who contrive the models claim that the product of the models validates them, and obtusely cling to this circular argument. Well, the world is slowly catching on to the fact that these GCM’s are part hoax.
In fact the ERL is reached by convection and convection is due to GHG. But worse than that, the earth’s surface is 71% water, and this cools by evaporation and so latent heat convected aloft is the principle means of cooling the surface. You adhere to a simplistic view of atmospheric processes that ignores the primary effects of water.
In fact, water in all of its phases, whether ice, liquid, or vapor, moderates temperature. Compare tropics with the Sahara. AGW theory ignores this principle. That is why the GCM’s fail abysmally.
But the global warmers ignore the abysmal failures and proceed bau.
davidmhoffer,
“Every day, all over the world, tens of thousands of engineers design everything from blankets to nuclear reactors using the precise physics that greg house insists are impossible. ”
If I understand Greg House correctly, he is saying that the back radiation cannot make the surface (or coffee) warmer than it started.
I think Greg is probably then extrapolating this idea, to arrive at the belief that back radiation can’t cause the surface temperature of the Earth to increase. Yet he has ignored the fact that energy from the sun is constantly being added to the system which does indeed make the Earth radiate at a higher temperature. That is why simple experiments with glass tubes cannot mimic what is happening in the Earths climate and analogies with thermos flasks do more to muddy the waters than to clarify.
Re Greg House.
I am aware of Woods’ experiment showing the ‘greenhouse effect’ is negligible, but so are warmist sites like Wikipedia – they also acknowledge this experiment and accept it – for greenhouses!
Looking at Global Warming however and you see the greenhouse glass is replaced by tropospheric heating, and the reflected infrared is now ‘back radiation’. No mention of greenhouses whatsoever so Woods’ findings do not apply!!! This is why the experiment must be specifically about CO2 to determine if it has any effect.
In a similar manner to Woods I would see it consisting of two tubes, as long as possible, insulated at the sides and base to prevent ambient heating, and sealed at the top with rock crystal. Sensitive thermocouples would be attached to the base and along the length. They should be put on equatorial mounts so they can follow the sun.
The basic experiment would be to double the CO2 in one of the tubes and check for temperature changes, over a 24 hour period. Variations would be : adding a fan to circulate the air, adding dry soil, adding water to the soil, and, just for fun, replicating the atmosphere of Venus.
I suspect the CO2 sensitivity would actually be zero as I see no possible mechanism for it to have any effect on the atmosphere. It would be interesting to find out.
LazyTeenager says:
January 26, 2013 at 5:09 pm
This is all very odd.
That would be cognitive dissonance kicking in. The very foundations of the CAGW conjecture on the one hand are being threatened by reality, and actual science on the other. If it were me, I’d go with the latter. Healthier emotionally and psychologically.
anticlimactic says:
January 25, 2013 at 3:30 pm
Also convection, which is a major, major player in the open atmosphere. It transports a huge amount of surface heat skyward to heights where CO2 can radiate it effectively. It can also be responsible for transporting water vapor and creating cloudiness that increases the Earth’s albedo which reduces the net solar energy absorption.
These effects cannot be readily reproduced in a small scale lab experiment.
The study ended with 2010, which was a hot year. Let’s someone ask them to include the data for the last two years, which were cooler, and ask how much those lower numbers and that additional “flat” time lowers their sensitivity number.
Mosher says: “the earth radiates at an altitude known as the ERL.. or effective radiating level. When you add GHGs to the atmosphere ( like doubling c02) you raise this level.”
Why stop there, Steve? You only described the “warming effect” of CO2. For some reason you and others who “believe” forget the other half of the equation. You only deal with surface energy but what happens to the energy in the atmosphere? GHGs are the gases that radiate energy to space. In other words, they cool the atmosphere. When you add more of them guess what happens?
Since CO2 is the primary GHG in the upper atmosphere (WV condenses out) adding more of this gas leads to increases in outgoing radiation. Since this cools the upper atmosphere it lowers the ERL and counters the GHE. That’s right, a negative feedback for CO2 warming (its small part of the GHE) is provided by CO2 itself. This effect is the reason there is no hot-spot. The extra energy trapped by CO2 at low levels in the atmosphere is radiated away by the CO2 at higher levels.
davidmhoffer says, January 26, 2013 at 10:39 pm : “Every day, all over the world, tens of thousands of engineers design everything from blankets to nuclear reactors using the precise physics that greg house insists are impossible.
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Physics is not impossible. “AGW physics” apparently is.
rgbatduke says:
January 25, 2013 at 8:07 am
The really, really amusing thing about this is the enormous impact that a tiny timespan has had on the estimate (which is absolutely on the right track). And that timespan is not “finished”. Every year with basically neutral temperature at this point shaves another 0.1 C off of the overall expected sensitivity,
henry says
we are on a curve spiraling down. by 2038 we will be back to where we were before, back in 1951.
this is an interesting article about this
http://blogs.24.com/henryp/2013/01/24/our-earth-is-cooling/
anticlimactic says, January 27, 2013 at 7:21 am: “Looking at Global Warming however and you see the greenhouse glass is replaced by tropospheric heating, and the reflected infrared is now ‘back radiation’. No mention of greenhouses whatsoever so Woods’ findings do not apply!!!”
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Wood’s finding is this: “back radiation does not affect the temperature of the source”.
Hence it applies to everything where there is back radiation. It applies to glass, gases, reflective coatings and so on.
Let me give you an example. Your finding is that “2 apples + 3 apples = 9 apples” is wrong. Does your finding apply to “2 tomatoes + 3 tomatoes = 9 tomatoes”?
OnDa says:
January 27, 2013 at 4:44 am
Wait, do we trust the science today or not? I thought we didn’t trust those scientists. I’m confused.
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In God we trust, All others bring DATA.
This paper is part of the climb down from the precipice they are hanging from. A song for the climastrologists.
anticlimactic;
I suspect the CO2 sensitivity would actually be zero as I see no possible mechanism for it to have any effect on the atmosphere.
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I suggest you read through this experiment by Heinz Hug as it is almost exactly the experiment you propose:
http://www.john-daly.com/artifact.htm
Be sure to also read through the zip file with reactions to the experiment that you will find at the top of the page.
1. The experiment shows conclusively that sensitivity in fact is not zero.
2. The conclusions drawn by Hug in regard to sensitivity in the atmospheric air column as a whole are invalid. The reasons for these are examined in detail in the zip file. In brief:
3. Hug’s experiment was conducted in an artificial atmosphere with a uniform water vapour. In the earth’s atmosphere, water vapour may range from 40,000 ppm at sea surface to nearly zero at high altitudes/cold temperatures. As the absorption spectra of water vapour and CO2 overlap, Hug’s experiment fails to take into account the fact that CO2’s effects would be more pronounced at higher altitudes and lower temperatures, hence his number is far too low.
4. Hug’s experiment also fails to consider the sheer scale of the atmospheric air column. Whatever contribution to warming that CO2 made over the 10 cm glass tube used in his experiment, it gets to make it again in the next 10 cm….and the next…and the next…. all the way to the top of the atmosphere several kilometers up.
All that said, we can draw the conclusion that the theoretical effects of CO2 do in fact exist, they have been measured over a 10 cm path length, and from this we can extrapolate that a still higher sensitivity would be arrived at once the entire atmospheric scale and the change in water vapour concentration from bottom to top of that scale is taken into account. Since building such an apparatus is not within our current technical capabilities, we cannot via experiment (at least this type of experiment) determine exactly what the sensitivity actually is across the atmospheric air column. Nor does such an experiment allow us to take into account secondary (feedback) effects which evidence is increasingly showing may well be negative. This is also important because it is the net effect that is of interest to us, not the effect of CO2 in isolation.
As for Greg House, as you correctly pointed out, the Woods experiment has nothing to do with the effects of CO2. Greg House knows this as it has been explained to him in multiple threads by multiple people. He knows also that he is referencing a century old experiment, and that there has been much discovered in physics since then, and multiple people have gone into great detail explaining this to him as well. He knows also about the Heinz Hug experiment, because I’ve directed him to it several times. He’s also had suggested to him by various luminaries such as Robert Brown at Duke, Leif Svalgaard, Ira Glickstein and others various experiments that he could conduct himself. Multiple people have pointed out to him that the mere fact that Venus is warmer than Mercury despite being farther from the sun, and that Earth is warmer than the moon, despite being the same distance from the sun, show conclusively that atmospheres do in fact result in warmer surface temperatures via the greenhouse effect. It has been pointed out to him that cloudy nights are warmer than clear sky nights, despite the clouds being much, much colder than the surface below them, yet they make it warmer. He’s been pointed at text books, free ones that are in use in universities where the laws of physics are explained in detail, the formulas and their application are easily understood, and which have been verified by experiment countless times. Yet through all this, Greg House steadfastly clings to a world view that ignores this entire body of evidence and seems to be based on a single experiment that is a century old and has nothing to do with the topic at hand in the first place.
The willful ignorance is instructive, for there simply is no difference between the ignorance that Greg House imposes on himself (and attempts to impose on others) and the willful ignorance of alarmists who similarly see the results they want to see simply by ignoring all the contrary data and science and attempting to impose their ignorance upon others.
davidmhoffer says
All that said, we can draw the conclusion that the theoretical effects of CO2 do in fact exist, they have been measured over a 10 cm path length, and from this we can extrapolate that a still higher sensitivity would be arrived at once the entire atmospheric scale and the change in water vapour concentration from bottom to top of that scale is taken into account
henry says
with all due respect, I say that nobody has conclusively proven, to me, at least, that the net effect of more CO2 is that of warming rather than cooling. I have explained my position on this here,
http://blogs.24.com/henryp/2011/08/11/the-greenhouse-effect-and-the-principle-of-re-radiation-11-Aug-2011/
For example, until fairly recently, it was not even known that CO2 also has absorptions in the UV region, which is how we now can identify it, qualitatively at least, on other planets, due to its back radiation…(=cooling)
So, unless you can provide me with the balance sheet, taking into account all the factors that I mention in my dissertation, WE don’t know if the net effect of more CO2 in the atmosphere is that of warming, cooling, or simply (close to) zero.
Failing you or anyone bringing me such relevant test results, on a balance sheet, showing me exactly how much warming and how much cooling the increase in CO2 causes, common sense would tell me that 50-100 ppm of a change in concentration of any one particular gas in the atmosphere, especially one on which all of our life and food (and drinks) depends, cannot make much of any difference whatsoever.
Cheers.
Henry
HenryP;
henry says
with all due respect, I say that nobody has conclusively proven, to me, at least, that the net effect of more CO2 is that of warming rather than cooling.
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With all “due respect”, I said nothing about the experiments and evidence I presented being of value in quantifying the net effect of CO2. In fact I went to considerable lengths to point out that the experiment I was discussing did NOT have the capability to quantify net effects. If you are going to offer me my “due respect” then have the decency to read what I said.
HenryP
From my reply above:
Nor does such an experiment allow us to take into account secondary (feedback) effects which evidence is increasingly showing may well be negative. This is also important because it is the net effect that is of interest to us, not the effect of CO2 in isolation.
Re Steven Mosher says:
January 26, 2013 at 4:31 pm
Yes it is simple. The higher the temperature at the Earth’s surface, the higher the radiative layer. Warm air is less dense so to maintain atmospheric pressure of about 1 atmosphere at the surface the column of air above a warm area must be higher than a cool area as it has less mass.
The mention of a vacuum flask brings up another area. You mention the silvering of a coffee flask preventing heat loss by radiation, but the key preventer of heat loss is the vacuum which slows cooling by conduction and convection. At normal Earth temperatures heat loss is mostly by conduction and convection, radiation only dominates at much higher temperatures. In fact nowadays coffee flasks rarely have a silvered lining as the glass is replaced by stainless steel which is a poor conductor – another indication of how little radiation matters at these temperatures.
The atmosphere is warmed primarily by conduction and convection at the Earth’s surface, not by radiation – standard school physics. Air warmed by the Earth must transmit it’s heat to cooler air or be forced to rise. If it fails to lose its heat it will rise to the radiative layer where it will eventually cool and fall back to earth. Warm air rises until it cools!
I am surprised at you stating that GHGs only have an effect at the radiative layer. I thought the idea was that the effect was throughout the atmosphere. This is my assumption based on your implication that my suggestion of an experiment would not be a meaningful test.
You say the atmosphere can not be recreated in the lab. Possibly not, but elements of it can. For example a tank containing CO2 at the density and temperature found at the radiative layer. How much radiation is absorbed, how much ‘back radiation’ is there, how long will a CO2 molecule hold the heat until it is radiated.
There are also indirect methods. Consider the Sahara Desert where temperature falls of 30C in a day are common. The radiative layer seems to have no problems disposing of the heat, and it poses serious questions about ‘back radiation’!. It also means that, at best, if there is any heating of the atmosphere by GHGs the effect would disappear within minutes of the sun setting. If GHGs had the effect you suggest then the days might be slightly warmer but the night temperatures would stay constant. Also it could not be additive, the effect would only be that achieved within any single day.
Finally, you mention water vapour as a GHG…but water vapour is the main cooling component in the atmosphere, transporting heat from the surface to the radiative layer, so not really a true GHG. I think that water, in all its forms, is the only substance on Earth which can have any real effect on climate, but mostly as a moderator. Every other influence is extra-terrestrial, mainly solar.
davidmhoffer says
Nor does such an experiment allow us to take into account secondary (feedback) effects which evidence is increasingly showing may well be negative. This is also important because it is the net effect that is of interest to us, not the effect of CO2 in isolation
henry says
I thought I had read the whole post earlier, and, in hindsight, stopped at the wrong point the 2nd time when I decided to comment on it. My apologies to you, david.
davidmhoffer says, January 27, 2013 at 10:30 am: “As for Greg House … He knows also about the Heinz Hug experiment, because I’ve directed him to it several times.”
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Of course, I know that, and you, I guess, know what I answered you: that that experiment was completely irrelevant to the issue in question, namely of the alleged effect of back radiation on the temperature of the source.
That experiment by Hug does not deal with the issue at all. (http://wattsupwiththat.com/2012/08/14/why-we-need-debate-not-consensus-on-climate-change/#comment-1059271)
Greg House;
Of course, I know that, and you, I guess, know what I answered you: that that experiment was completely irrelevant to the issue in question, namely of the alleged effect of back radiation on the temperature of the source.
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Demonstrating once again your profound and disturbing inability to understand either the physics I have presented or the physics you have presented. If you actually had the first effing clue as to what radiative physics actually is you’d understand why the Hug experiment is precisely the proof you request, but you would rather remain ignorant.