William and me had some related discussions, eg here: http://scienceblogs.com/stoat/2007/05/more_hot_air.php#comments
You may have seen that anyway, as you've commented on his blog yourself. I've got several comments: 1. If there was enough urgency, I think a great deal could be done to cut emissions very rapidly. I've commented on this in the past in the peak oil context: http://heikoheiko.blogspot.com/2006/06/my-take-on-peak-oil-doomerism.html Think of what the US say was willing to do in WWII. With that level of willingness for sacrifice, emissions could be reduced by 90% plus virtually overnight. Rather arguably the urgency isn't such, but if it were, you'd find that outlawing driving and forced reallocation of existing housing stock could be extremely effective. 2. Carbon dioxide sequestration via mineralisation seems to be feasible at a cost of $100 per tonne. http://www.ecn.nl/en/bkm/r-d-programme/environmental-risk-assessment/research-programmes/mineral-co2-sequestration/ I don't see why we couldn't drive emissions well below zero in a few decades. It's far from a given that we'll still have emissions greater than zero in 2050, let alone 2100. 3. We are already doing "geo-engineering" with aerosols, it's even major geo-engineering as the forcing from tropospheric sulfate aerosols is of a similar (though much more uncertain) magnitude as CO2. Rather than using stratospheric aerosols to completely off-set greenhouse gases, why not at least consider using them to (partially) compensate for declining tropospheric aerosols? 4. I find demands for "action" in the generic somewhat frustrating. We are "acting" already in many ways (eg the US and Europe have various efficiency and renewables standards and support nuclear power to varying degrees). Because the word "action" doesn't contain any detail involving anything difficult/unpopular (such as replacing all coal fired generation with nuclear, or imposing gasoline taxes of $10 per gallon, or a 400% tax on cars), this generic call sometimes seems like an avoidance strategy, a cop-out, particularly when it's used by governments. Eg, when European politicians decide on a 2C target and say virtually nothing on how they think it'll get achieved ... --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
