13th February, 2011 - Posted by admin - Comments Off
Has UK Government underestimated climate change?
Professor Stephen Salter is not a climate scientist but his letter in the Independent yesterday Deadly peril of loss of sea ice is worrying
The area of Arctic sea ice in late summer declined substantially in the decade until 2007 and has been stable since then. But in 2010 the area of sea ice which was more than two years old, and was therefore thin ice, was substantially less than ever before.
A reasonable judgment is that there is a 40 per cent chance that the sea-ice area will decline significantly to less than 2.5 million sq km in 2011 and a one in three chance the area will fall to less than 2 million sq km as measured by the Cryosphere Today. The minimum ice area in 2010 was 3 million sq km using Cryosphere Today figures.
Since ice reflects sunlight and water absorbs sunlight, should the ice area decline then the Arctic will warm in late summer. This may well warm the Tundra which will defrost faster than at present. The result will be that the greenhouse gases carbon dioxide and methane will be released into the atmosphere leading to further warming and a runaway greenhouse event and the collapse of civilization.
We believe that should there be a substantial decline in sea-ice area then by marshalling all the resources of humanity and cutting greenhouse-gas emissions substantially and using geo-engineering, then the global climate and civilization can be saved. We need to be ready to start in autumn 2011 if the situation goes badly in late summer 2011.
Earlier posts discuss a theory, which may be key to UK GOvernemnt policy, the Trillion Tonne Scanario, Allen et al, “Warming caused by cumulative carbon emissions towards the trillionth tonne”. They say
Total anthropogenic emissions of one trillion tonnes of carbon (3.67 trillion tonnes of CO2), about half of which has already been emitted since industrialization began, results in a most likely peak carbon-dioxide induced warming of 2 degrees Celsius above pre-industrial temperatures, with a 5–95% confidence interval of 1.3–3.9 degrees Celsius.
But feedbacks effects such as those described by Professor Salter were almost certainly omitted from the computer simulations used by Allen et. al. Ray Pierrehumbert of RealCLimate published a similar paper – he addresses this on RealClimate “Losing time, not buying time“. In all probability the climate models used for this work were similarly lacking.
The theories of Professors Allen and Humbert are not just of academic interest. They have been the backbone of UK Governemnt climate policy.
It’s not just the permafrost feedbacks that may be missing from the climate modelling for the Trillion Tonne Scenario. For example:
Spielhagen et al. “Enhanced Modern Heat Transfer to the Arctic by Warm Atlantic Water”
Should Allen and Pierrehumbert reassess their work?
Have they underestimated climate change?
Does this give support to Stephen Salter and friends?
Stop press: National Snow and Ice Data Center, 16 February 2011
Now, permafrost is thawing in a warming climate and—just like the broccoli—the biomass will thaw and decay, releasing carbon into the atmosphere like any other decomposing plant material, Schaefer said. To predict how much carbon will enter the atmosphere and when, Schaefer and coauthors modeled the thaw and decay of organic matter currently frozen in permafrost under potential future warming conditions as predicted by the Intergovernmental Panel on Climate Change.
They found that between 29–59 percent of the permafrost will disappear by 2200. That permafrost took tens of thousands of years to form, but will melt in less than 200, Schaefer said.
The scientists used a model to predict how much carbon the thawing will release. They estimate an extra 190 plus or minus 64 gigatons of carbon will enter the atmosphere by 2200—about one-fifth the total amount of carbon currently in the atmosphere today. Carbon emissions from thawing permafrost will require greater reductions in fossil fuel emissions, to limit the atmospheric carbon dioxide to some maximum value associated with a target climate, Schaefer said. “It means the problem is getting more and more difficult all the time,” he said. “It is hard enough to reduce the emissions in any case, but now we saying that we have to reduce it even more.”