Re: [geo] Solar Radiation Management section of National Academy's America's Climate Choices report

[John Nissen]

Thanks, Ken. Others might like to read bios here: http://americasclimatechoices.org/scienceslate.shtml Is there any new perspective on geoengineering in the report?  There is no mention of SRM to save the Arctic sea ice!  But there is a small section discussing what constitutes an emergency: [quote] Develop metrics and methods for informing discussions and decisions related to “climate emergencies”. There are at least two components to this research need. For use of SRM as a potential "back-stop option” in the case of an emerging “climate emergency ", improved observations and understanding of climate system thresholds, reversibility, and abrupt changes (see Chapter 6)—for example, observations to let us know when an ice sheet or methane hydrate field may become unstable (e.g., Khvorostyanov et al., 2008; Shakhova et al., 2010)—could inform societal debate and decision making about needs for deployment of a climate intervention system. Second, there is no consensus on what constitutes a "climate emergency", nor is there a consensus regarding when an SRM deployment might be warranted. The notion of an "emergency" is not simply a scientific concept, but one that involves both scientific facts and human values—quite similar to discussions about “dangerous interference in the climate system” (e.g., Dessai et al., 2004; Gupta and van Asselt, 2006; Hansen, 2005; Lorenzoni et al., 2005; Oppenheimer, 2005; Smith et al., 2009). To some people, losing Arctic ecosystems constitutes a climate emergency, whereas to others the declaration of an “emergency” might require widespread loss of human life. Therefore, to inform a broader discussion of how society wants to address issues of risk, climate intervention cannot be studied in isolation but must be placed in a broader context considering, for example, drivers of climate change, climate consequences, socio-political systems, and human values. [end quote] So, Ken, what do you think constitutes a climate emergency to justify SRM?  How much loss of Arctic sea ice?  How much risk from methane release?  How much risk of sea level rise from Greenland ice sheet disintegration?  Can SRM ever be justified on the precautionary principle - and if not why not?  What is proper risk management?  What calculations are needed to justify geoengineering rather than further delay? Cheers, John -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineer...@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.