Transition Sheffield - Discussion Forum

James hansen wrote: The final version of "Target Atmospheric CO2: Where Should Humanity Aim?" in The Open Atmospheric Science Journal is available at http://dx.doi.org/10.2174/1874282300802010217

You can click on the main paper and supporting material individually. The two are combined in one pdf on the GISS web site at http://pubs.giss.nasa.gov/abstracts/200 ... _etal.html

BTW, I think that the Supporting Material contains some interesting stuff.

NASA decided not to make a press release for the paper, but Yale did one http://www.eurekalert.org/pub_releases/ ... 110708.php The draft press release that I wrote and "Q&A" about the paper are at http://www.columbia.edu/~jeh1/mailings/ ... Target.pdf

It is difficult to generate the attention that the topic deserves because the basic conclusions were already presented in my talk at the December 2007 AGU meeting. Also the first draft of the paper (available in arXiv, as is the final version) appeared on several blogs and was discussed in several newspapers, which discourages media attention to the final improved version.

The long delay between first draft and final paper was my fault. The principal demand of the journal referees, addition of a "caveats and uncertainties" section (section 4.5 in the main paper and section 18 in the Supplementary Material), could have been completed in a week or two, but it took me ~two months because of other obligations. I caused another delay by not checking typesetting in the proofs carefully enough, requiring an extra iteration of proofs. Bottom line: I think that the "Open" publication method, which includes full peer review but results in a paper freely available throughout the world, is promising and I intend to pursue it further.

http://www.columbia.edu/%7Ejeh1/mailing ... erland.pdf

Abstract: Paleoclimate data show that climate sensitivity is ~3°C for doubled CO2, including only fast feedback processes. Equilibrium sensitivity, including slower surface albedo feedbacks, is ~6°C for doubled CO2 for the range of climate states between glacial conditions and ice-free Antarctica. Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, the planet being nearly ice-free until CO2 fell to 450 ± 100 ppm; barring prompt policy changes, that critical level will be passed, in the opposite direction, within decades. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that. The largest uncertainty in the target arises from possible changes of non-CO2 forcings. An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.

Climate threat. The world’s temperature has increased about 1°F over the past few decades, about 2°F over land areas. Further warming is “in the pipeline” due to gases already in the air (because of climate system inertia) and inevitable additional fossil fuel emissions (because of energy system inertia).

Although global warming to date is smaller than day-to-day weather fluctuations, it has brought global temperature back to approximately the highest level of the Holocene, the past 10,000 years, the period during which civilization developed. Effects already evident include:

1. Mountain glaciers are receding worldwide and will be gone within 50 years if CO2 emissions continue to increase. This threatens the fresh water supply for billions of people, as rivers arising in the Himalayas, Andes and Rocky Mountains will begin to run dry in the summer and fall.

2. Coral reefs, home to a quarter of biological species in the ocean, could be destroyed by rising temperature and ocean acidification due to increasing CO2.

3. Dry subtropics are expanding poleward with warming, affecting the southern United States, the Mediterranean region, and Australia, with increasing drought and fires.

4. Arctic sea ice will disappear entirely in the summer, if CO2 continues to increase, with devastating effects on wildlife and indigenous people.

5. Intensity of hydrologic extremes, heavy rains, storms and floods on the one hand, and droughts and fires on the other, are increasing.

Some people say we must learn to live with these effects, because it is an almost god- given fact that we must burn all fossil fuels. But now we understand, from the history of the Earth, that there would be two monstrous consequences of releasing the CO2 from all of the oil, gas and coal, consequences of an enormity that cannot be accepted.

One effect would be extermination of a large fraction of the species on the planet. The other is initiation of ice sheet disintegration and sea level rise, out of humanity’s control, eventually eliminating coastal cities and historical sites, creating havoc, hundreds of millions of refugees, and impoverishing nations.

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IS IT TOO LATE FOR CLIMATE?

Not according to NASA's James Hansen. His testimony, along with Tim Helweg-Larsen of PIRC to UK gov't Environmental Audit Committee November 26th, 2008. MP3 68 min 16 MB Lo-Fi. Scary need-to-know info, along with a way out, if we act fast.

http://www.ecoshock.org/DNclimate08.html

'We have only four years left to act on climate change - America has to lead'

Barack Obama, who will be inaugurated as US president on Tuesday. His four-year administration offers the world a last chance to get things right, Hansen said. If it fails, global disaster - melted sea caps, flooded cities, species extinctions and spreading deserts - awaits mankind.

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the idea of continuing with "cap-and-trade" schemes, which allow countries to trade allowances and permits for emitting carbon dioxide, must now be scrapped, he insisted. Such schemes, encouraged by the Kyoto climate treaty, were simply "weak tea" and did not work.

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plans to include carbon trading schemes in talks about future climate agreements were a desperate error, he said. "It's just greenwash. I would rather the forthcoming Copenhagen climate talks fail than we agree to a bad deal," Hansen said.

Only a carbon tax, agreed by the west and then imposed on the rest of the world through political pressure and trade tariffs, would succeed in the now-desperate task of stopping the rise of emissions, he argued. This tax would be imposed on oil corporations and gas companies and would specifically raise the prices of fuels across the globe, making their use less attractive. In addition, the mining of coal - by far the worst emitter of carbon dioxide - would be phased out entirely along with coal-burning power plants which he called factories of death.

"Coal is responsible for as much atmospheric carbon dioxide as other fossil fuels combined and it still has far greater reserves. We must stop using it." Instead, programmes for building wind, solar and other renewable energy plants should be given major boosts, along with research programmes for new generations of nuclear reactors.