Kooiti MASUDA wrote: > It seems that there are as much land where water availability increases > as where it decreases. But it seems to me that the distribution of > increases and decreases is something unhelpful for agricultural > productivity.
This I do not doubt (well, all model projections are somewhat doubtful and the worst scenarios are probably somewhat exaggerated, but for the sake of argument I accept it here). However, it also seems clear that there are much more pressing and urgent problems in many areas. Groundwater use is completely unsustainable in many areas: http://www.newscientist.com/article.ns?id=dn6321 (it is Fred Pearce, so read with a bucket of salt) There was more in the news recently about how rivers were basically used up over much of the world, which I've lost the reference to. It'll be in the news again in a few weeks or months, no doubt. Yet global population is increasing. I realise that the lack of water may somewhat challenge my previous assertion that productivity will continue to rise, but I'm trying to make a more fundamental point here. Even if one frames the research in order to present anthropogenic climate changes over the net century as the last straw to break the camel's back, it is still probably not meaningful to focus on this straw to the exclusion of the rest of the bale. For example, simple recharge ponds could both help to deal with extreme rainfall and also give it time to soak in to replenish ground water. It is also well known that management of vegetation cover can have substantial effects. I'm very suspicious of anyone who presents a "ceteris paribus" sensitivity experiment as if it is an actual prediction, since it is obvious that ceteris are not going to be at all paribus a couple of decades or more into the future. The crop yield predictions even pretend that there will be no new varieties developed in the coming years, even as our genetic engineering technology is taking off. WTF? James --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
