DOI: http://dx.doi.org/10.1065/espr2007.07.439
The connection between the two items in our title may not be immediately obvious to the reader, but we hope in this article to establish the relationship between them.
In Paris, on 2 February 2007, the Working Group I of the Intergovernmental Panel on Climate Change (IPCC) adopted the Summary for Policymakers of the first volume of Climate Change 2007, also known as the Fourth Assessment Report (AR4). This Summary for Policymakers, which describes estimations of projected future climate change, is based on the past IPCC assessments and the new findings in relevant understanding that have been achieved in the past six years of research (since the Third Assessment Report). Among its basic conclusions are (verbatim) the following:
1. Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.
2. At continental, regional, and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in Arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones.
3. For the next two decades a warming of about 0.2°C per decade is projected for a range of SRES (Special Report on Emission Scenarios) emission scenarios. Even if the concentrations of all greenhouse gases and aerosols had been kept constant at year 2000 levels, a further warming of about 0.1°C per decade would be expected.
4. Anthropogenic warming and sea level rise would continue for centuries due to the timescales associated with climate processes and feedbacks, even if greenhouse gas concentrations were to be stabilized.
The report was produced by some 600 authors from 40 countries, reviewed and revised by over 620 experts and a large number of government reviewers as well as representatives from 113 governments. |
