Extracts from IPCC 4th Report Summary for Policymakers
Working Group II to the IPCC 4th Report
This material is sourced from the “IPCC 4th Report Climate Change Impacts Adaptation and Vulnerability.”
1. Current knowledge about observed impacts of climate change on the natural and human environment.
The IPCC 4th Report Climate Change Impacts Adaptation and Vulnerability summary looks at the relationship between observed climate change and recent observed changes in the natural and human environment. A full consideration of observed climate change is provided in the IPCC Working Group I Fourth Assessment.
Information here is based largely on data sets that cover the period since 1970. The number of studies of observed trends in the physical and biological environment and their relationship to regional climate changes has increased greatly since the Third Assessment in 2001. The quality of the data sets has also improved. There is, however, a notable lack of geographic balance in data and literature on observed changes. This means information for developing countries is scarce and as a result the developing countries are not well represented. More on observed impacts
2. Current knowledge about future impacts
The following is a selection of the key findings regarding projected impacts, as well as some findings on vulnerability and adaptation, in each system, sector and region for the range of (unmitigated) climate changes projected by the IPCC over this century judged to be relevant for people and the environment.
The impacts frequently reflect projected changes in precipitation and other climate variables in addition to temperature, sea level and concentrations of atmospheric carbon dioxide. The magnitude and timing of impacts will vary with the amount and timing of climate change and, in some cases, the capacity to adapt.
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.
Fresh water resources and their management
Food, fibre and forest products
Coastal systems and low-lying areas
3. More specific information is now available across the regions of the world concerning the nature of future impacts. From the IPCC 4th Report Climate Change Impacts Adaptation and Vulnerability, future impacts are outlined for the following regions:
Australia and New Zealand
4. The IPCC 4th Report Climate Change Impacts Adaptation and Vulnerability show magnitudes of impact can now be estimated more systematically for a range of possible increases in global average temperature.
Since the IPCC Third Assessment, many additional studies, particularly in regions that previously had been little researched, have enabled a more systematic understanding of how the timing and magnitude of impacts may be affected by changes in climate and sea level associated with differing amounts and rates of change in global average temperature. More on magnitudes of impact.
5. Impacts due to altered frequencies and intensities of extreme weather, climate, and sea level events are very likely to change.
Since the IPCC Third Assessment, confidence has increased that some weather events and extremes will become more frequent, more widespread and/or more intense during the 21st century; and more is known about the potential effects of such changes. More on frequencies and intensities.
6. Current knowledge about responding to climate change.
Some adaptation is occurring now, to observed and projected future climate change, but on a limited basis. There is growing evidence since the IPCC Third Assessment of human activity to adapt to observed and anticipated climate change. For example, climate change is considered in the design of infrastructure projects such as coastal defence in the Maldives and The Netherlands, and the Confederation Bridge in Canada. Other examples include prevention of glacial lake outburst flooding in Nepal, and policies and strategies such as water management in Australia and government responses to heat waves in, for example, some European countries. More detail on climate adaptation and mitigation.
Material is sourced from the “IPCC 4th Report Climate Change Impacts Adaptation and Vulnerability”