- Associated with human greenhouse gas production is the release of fine particle known as aerosols which have a temporary cooling effect (they last in the atmosphere less than a week).
- Aerosol cooling probably reduced global warming "by about half over the past century". In the paper Hansen et al estimate the temporary cooling "aerosol forcing -1.6 ± 0.3 watts per sq. m.". This is around 1.2 degrees Celsius. That is, without the aerosols associated with burning fossil fuels, the planetary would be more than a degree warmer!
- The amount is uncertain because global aerosols and their effect on clouds are not measured accurately. Overcoming this gap in knowledge is urgent.
- To prevent catastrophic global warming human greenhouse gas emission must cease, but this will also end the aerosol cooling effect and the full heating effect of our "Faustian bargain" will be revealed.
30 March 2013
Intro note: NASA's James Hansen and colleagues Pushker Kharecha and Makiko Sato have a new paper, "Climate forcing growth rates: doubling down on our Faustian bargain," in the current issue of Environmental Research Letters. They have also summarised their findings in an overview out today, and reproduced below. Main points include:
13 March 2013
Unfortunately, as things now stand, that conveyor belt is rusty and full of gaps. Clever ideas get stuck in our heads, or fail to make it across the “valley of death” between labs and markets, or fail to take hold and grow in those markets. We call these gaps “market failures,” but that is a misleadingly passive construction. The conveyor belt is not something that exists in Platonic market space, a priori, that we merely need to uncover. It is something we must build, consciously, using markets among other tools.
07 March 2013
Global climate change and land degradation have to be put on a war footing internationally - meaning that all nations need to pull together and treat this threat as we would a war. . . . Only through uniting and diverting all the resources required to deal with climate change and land degradation can we avert unimaginable tragedy. We have all the money we need. All we cannot buy is time. – Allan SavoryI've been a climate activist since the millennium turned, twelve long years ago. Like so many others I've rallied, marched, petitioned, organized, lectured, blogged, fumed, despaired, studied, argued and hoped. Now, sadly, it seems that we have to come to terms with a painful reality: Our fight against global warming has not worked.