From ETH Zurich: Underestimated future climate change?
25.11.2013 | Fabio Bergamin
New model calculations by ETH researcher Thomas Frölicher show that global warming may continue after a stoppage of CO 2 emissions. We cannot rule out the possibility that climate change is even greater than previously thought, says the scientist.
Many scientists believe that global warming will come to an end if, some day, human succeeds in stopping the release of greenhouse gas emissions into the atmosphere. It would, indeed, be hotter on Earth than before industrialisation, but nonetheless it would not get even hotter. Climate physicist Thomas Frölicher questions this notion by using model calculations and creates a more pessimistic picture in a study published in the scientific journal Nature Climate Change. According to his model calculations, it is very possible that the Earth’s atmosphere could continue to warm for hundreds of years even after a complete stop of CO2 emissions, and that temperature levels stabilise at an even higher level at a later stage.
“In the long term, the temperature increase could be 25 per cent greater than assumed today,” says the scientist, who carries out research as an Ambizione Fellow of the Swiss National Science Foundation in ETH professor Nicolas Gruber’s group.
A more realistic model
Frölicher and his co-authors from the USA use one of the world’s leading climate models for their calculations, the ESM2M model that was developed at the Geophysical Fluid Dynamics Laboratory in Princeton. It represents physical and biogeochemical processes – such as the exchange of greenhouse gases and heat with the oceans – at a far more detailed level than many previous models. “The model is closer to reality,” summarises Frölicher.
In this model, the researchers simulated an Earth on which 1800 gigatons of carbon are emitted instantaneously into the atmosphere. By way of comparison: 1000 gigatons are believed to lead to a global warming of 2 degrees Celsius. Frölicher’s model calculation corresponds to an extremely simplified scenario. In reality, greenhouse gases are released over a period of several decades or centuries. The simulations, however, are well suited to illustrate fundamental principles, explains the climate scientist.
Regional ocean heat uptake is the key
“Much of the CO2 released into the atmosphere and the heat trapped by the CO2 goes into the ocean sooner or later – approximately 90 per cent of the excess heat has been taken up by the ocean over the last 40 years,” explains Frölicher. The regional uptake of heat, however, is crucial. To date, not enough attention has been given to the regional heat uptake of the world’s oceans in climate research. With the help of the ESM2M climate model, the scientists are able to show that a change in ocean heat uptake in the polar regions has a greater effect on the global mean atmospheric temperature than a change near the equator. The researchers use these differences to explain why their calculations contradict a scientific consensus that global atmospheric temperature would remain constant if emission were suddenly stopped.
Frölicher acknowledges that his calculations are based on a single climate model and it should not be ruled out that different results might be obtained if other climate models are used. However, it is evident to him that the magnitude of global warming in the next few centuries is less clear than previously thought. Rather, we should consider that climate change could turn out to be even greater than we have thought until now, says the scientist. “If our results stand up to a repetition with other modern and detailed models, this would mean that global warming considered beyond the end of this century has been significantly underestimated to date.”
A 25 per cent increase in global warming would also mean that humans could release 25 per cent less greenhouse gases to achieve climate goals such as the two-degrees Celsius target. In its assessment report published a few months ago, the Intergovernmental Panel on Climate Change IPCC assumes that limiting the global warming to less than two-degrees Celsius will require cumulative CO2 emissions to stay below 1000 gigatons of carbon. Since preindustrial times, humans have already consumed around half of this budget, i.e. 500 gigatons. If Frölicher’s results were correct, the “emissions cake” would be only three-quarters, i.e. 750 gigatons instead of 1000 billion tons of carbon. Thus, limiting the warming to 2 degrees would require keeping future cumulative carbon emission below 250 gigatons of carbon, only half of the already emitted amount of 500 gigatons.
Literature Reference
Frölicher TL, Winton M, Sarmiento JL: Continued global warming after CO2 emissions stoppage. Nature Climate Change, Adavance Online Publication 24 November 2013, doi: 10.1038/nclimate2060
Martin says:
November 26, 2013 at 4:52 am
“Given that water takes hundreds if not thousands of years to circulate from the depths of the deepest oceans to the surface, using air temperature to warm the seas would be an inefficient solution. Whereas infra-red can penetrate several hundred metres depth and is possibly a far more effective way of warming the oceans.”
You are wrong, Martin. IR only penetrates the skin layer; maybe a hundred micrometers.
It is UV that can reach hundreds of meters of depth; that’s why light gets progressively more blue the deeper you dive.
wsbriggs says:
November 26, 2013 at 3:30 am
“As a graduate of the ETH this saddens piece me tremendously”
Yep. They used to have a splendid reputation. And the ETH is not even on EU territory; so it is not obvious why they partake in the UN madness.
Another Ian says:
November 26, 2013 at 1:57 am
“Didn’t ETH also do Pascal?”
Yes; Niklaus Wirth: He created Pascal, Modula, and Oberon.
I cannot agree with Frölicher. His first sentence reads: “…Recent studies have suggested that global mean surface temperature would remain approximately constant on multi-century timescales after CO2 emissions 1, 2, 3, 4, 5, 6, 7, 8, 9 .” The claim by these nine references that temperature will stabilize for centuries after the addition of CO2 has stopped cannot be checked. His implied assertion that addition of carbon dioxide will warm the air is also rendered false by the fact that addition of CO2 for the last 15 years has had no influence on global temperature. People associated with the global warming movement do not wish to admit this. They use alternate language like “pause” or “hiatus” to refer to this cessation of warming. Or they claim that the missing heat has disappeared into the ocean bottom. But if someone finds a fifteen year stretch of no warming should they not make it their business to find out if this is something new? I say this because there really was another stretch of no-warming in the eighties and nineties that lasted for 18 years. But it was covered up by a fake warming by guardians of official temperature until last fall. I discovered this fake warming while doing research for my book “What Warming?” [1], even put a warning about it into the preface of the book. Nothing happened for two years but then suddenly, last fall, the big three of temperature, GISTEMP, HadCRUT, and NCDC decided to give up showing that fake warming. What they did was to align their eighties and nineties with satellites that do not show it. This was done secretly and required cross-Atlantic cooperation. We can now add these “liberated” 18 years to the current 15 year standstill and find that there has been no greenhouse warming whatsoever for the last 35 years. With this history of no-warming it is silly to talk of carbon dioxide warming that plainly does not exist. Obviously the Arrhenius greenhouse warming is not there. It so happens that this is exactly what the greenhouse gas theory of Ferenc Miskolci requires. His theory that came out in 2007 [2] postulates that if more than one greenhouse gas simultaneously absorb in the IR an optimum absorption window is established that they jointly maintain. In the earth atmosphere the greenhouse gases that matter are carbon dioxide and water vapor. Their joint absorption window has an optical thickness of 1.87 in the IR. If we now add carbon dioxide to air it will start to absorb and the optical thickness will go up. But as soon as this happens water vapor will start to diminish, rain out, and the optical thickness is restored to its previous optimal value. When his paper came out he was disbelieved by the global warming establishment and shouted down. But by 2010 he had empirical proof. He used NOAA database of radiosonde measurements [3] that goes back to 1948 to study the absorption of IR by the atmosphere over time. And discovered that absorption had been constant for the last 61 years while carbon dioxide at the same time increased by 21.6 percent. This means that addition of this substantial amount of carbon dioxide to air had no influence on the absorption of IR by the atmosphere. And no absorption means no greenhouse effect, case closed.
[1] Arno Arrak, “What Warming? Satellite view of global temperature change” (CreateSpace 2010)
[2] Ferenc M. Miskolczi, “Greenhouse effect in semi-transparent planetary atmospheres” Quarterly Journal of Hungarian Meteorological Service 111(1):1-40 (January-March 2007).
[3] Ferenc M. Miskolczi, “The stable stationary value of the Earth’s global average atmospheric greenhouse-gas optical thickness” E&E 21(4):243-262 (2010)
Very good summary of Miskolczi’s theory, Arno.
But we already know that CO2 emissions can continue long after the warming has stopped ….
ETH: Instead of going from bad to worse, they’ve gone from Wirth to worthless….
Sad, lot of good research, etc., Pascal only one of the results…
Even though they’re not in the EU, the money still flows wherever AGW goes.
Didn’t Switzerland introduce a law a couple of years ago about protecting plants
from the “pain they endure” when they are harvested, and that they have rights too?