The second part of the Fourth Assessment Report by the Intergovernmental Panel on Climate Change has been released, two months after the first part was published.
In the associated Summary for Policymaker report (SPM):
- Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases. (Page 2)
- A global assessment of data since 1970 has shown it is likely6 that anthropogenic warming has had a discernible influence on many physical and biological systems. (Page 3)
- Other effects of regional climate changes on natural and human environments are emerging, although many are difficult to discern due to adaptation and non-climatic drivers. (Page 4)
What we know on anthropogenic climate change?
- More specific information is now available across a wide range of systems and sectors concerning the nature of future impacts, including for some fields not covered in previous assessments. (Page 7)
- More specific information is now available across the regions of the world concerning the nature of future impacts, including for some places not covered in previous assessments. (Page 10)
- Magnitudes of impact can now be estimated more systematically for a range of possible increases in global average temperature. (Page 14)
- Impacts due to altered frequencies and intensities of extreme weather, climate, and sea level events are very likely to change. (Page 16)
- Some large-scale climate events have the potential to cause very large impacts, especially after the 21st century. (Page 17)
About our possible response to anthropogenic climate change:
- Some adaptation is occurring now, to observed and projected future climate change, but on a limited basis. (Page 18)
- Adaptation will be necessary to address impacts resulting from the warming which is already unavoidable due to past emissions. (Page 18)
- A wide array of adaptation options is available, but more extensive adaptation than is currently occurring is required to reduce vulnerability to future climate change. There are barriers, limits and costs, but these are not fully understood. (Page 18)
- Vulnerability to climate change can be exacerbated by the presence of other stresses. (Page 19)
- Future vulnerability depends not only on climate change but also on development pathway. (Page 19)
- Sustainable development can reduce vulnerability to climate change, and climate change could impede nations’ abilities to achieve sustainable development pathways. (Page 19)
- Many impacts can be avoided, reduced or delayed by mitigation. (Page 20)
- A portfolio of adaptation and mitigation measures can diminish the risks associated with climate change. (Page 20)
- Impacts of climate change will vary regionally but, aggregated and discounted to the present, they are very likely to impose net annual costs which will increase over time as global temperatures increase. (Page 20)
In the report, the media seems to be zeroing on one point: the winners and losers of climate change. The esteemed NYT has a great graphics on the matter. The BBC has produced another graphics describing the effects of climate change all over the world. At the BBC:
The supply of water is very likely to increase at higher latitudes and in some wet tropics, including populous areas in east and southeast Asia. It is very likely to decrease over much of the mid-latitudes and dry tropics, which are presently water-stressed areas. [Climate change around the world. BBC News. April 6 2007]
From the SPM itself:
For more legend, read the part 2 of the AR4.
In January in the aftermath of New Orleans of Malaysia, the government promised a report of climate change. Where is that report now, I wonder?
