Friday, September 27, 2013

The Most Important Paragraph in Today's 5AR SPM?

Perhaps the most important change in today's IPCC 5AR WG1 Summary for Policymakers (SPM) is a single paragraph on geoengineering:
Methods that aim to deliberately alter the climate system to counter climate change, termed geoengineering, have been proposed. Limited evidence precludes a comprehensive quantitative assessment of both Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR) and their impact on the climate system. CDR methods have biogeochemical and technological limitations to their potential on a global scale. There is insufficient knowledge to quantify how much CO2 emissions could be partially offset by CDR on a century timescale. Modelling indicates that SRM methods, if realizable, have the potential to substantially offset a global temperature rise, but they would also modify the global water cycle, and would not reduce ocean acidification. If SRM were terminated for any reason, there is high confidence that global surface temperatures would rise very rapidly to values consistent with the greenhouse gas forcing. CDR and SRM methods carry side effects and long-term consequences on a global scale. {6.5, 7.7} 
I believe this is the first time any mention of geoengineering has appeared in an IPCC report.... It seems mostly an accurate and not surprising summary of the state of knowledge of geoengineering, though Ken Caldiera has already pointed out on the geoengineering discussion list that the word "suddenly" was left out of the penultimate sentence, i.e "If SRM were suddenly terminated for any reason...."

That's significantly different from what New Scientist reported a few days ago:
Global warming is irreversible without massive geoengineering of the atmosphere's chemistry. This stark warning comes from the draft summary of the latest climate assessment by the Intergovernmental Panel on Climate Change.
so we'll see what the full WG1 says.

But just the fact that this paragraph is there in the SPM seems important -- almost like it's a placeholder for what's going to come in the 6AR (if there is such a thing) or future reports from the IPCC. Like it's setting the table.... The Guardian reported several days ago that
Russia is pushing for next week's landmark UN climate science report to include support for controversial technologies to geoengineer the planet's climate, according to documents obtained by the Guardian.
though they may have a conflict between this and the economic opportunities they see opening up from climate change (especially, of course, oil and gas drilling in the Arctic).

Ten years from now the only real argument left may be whether it's wise to finally begin geoengineering, since we seem unable to do anything else about climate change.


Unknown said...

"wise to finally begin geoengineering"?

Are you joking? They have been at it for year already!

David Appell said...

Not officially. Not except for a few CDR projects in recent years. But, yes, several scientists have been talking about geoengineering, with increasing seriousness, since Paul Crutzen's 2006 paper.