Abstract
The 1992 UN Framework Convention on Climate Change, ratified by the vast majority of nations, commits most countries to "avoid dangerous anthropogenic interference with the climate system". This includes, ecosystems, food production and sustainability sectors. The current course of climate change and related impacts is exceeding most earlier estimates, and projections for the future typically range from at least another 1.5 to 2 degrees Celsius above now - which is already about 0.8 degrees warmer than pre-industrial levels - up to a potentially catastrophic 6 degrees warming by 2100, with even more in the 22nd century. This dangerous prospect has fueled a global debate about effective and equitable strategies to adapt to those changes that cannot be mitigated and to mitigate those that can't easily be adapted to. The most daunting possibilities include exceeding irreversible "tipping points", like melting much of Greenland ice sheet causing many meters of sea level rises for millennia, to a commitment for extinction of tens of percent of known species, among many other potential damages. Though not all impacts are detrimental, the vast majority are, especially for warming of more than a few degrees. Therefore, what are the prospects for a combination of adaptation and mitigation strategies being approved by world governments at Copenhagen in December 2009, and will even a strong set of policies be adequate to "avoid dangerous anthropogenic interference with the climate system", including both social and natural systems, as required by international agreement.
By Stephen H. Schneider and Terry L. Root
Stanford University
Woods Institute for the Environment
http://climatechange.net/
Stephen Schneider is the Arne Naess Chair 2009, Centre for Development and the Environment (SUM), University of Oslo.