The sensitivity, adaptive capacity, and vulnerability of natural and human
systems to climate change, and the potential consequences of climate change,
are assessed in the report of Working Group II of the Intergovernmental Panel
on Climate Change (IPCC), Climate Change 2001: Impacts, Adaptation, and Vulnerability.
This report builds upon the past assessment reports of the IPCC, reexamining
key conclusions of the earlier assessments and incorporating results from more
recent research. 2
Observed changes in climate, their causes, and potential future changes are
assessed in the report of Working Group I of the IPCC,
Climate Change 2001: The Scientific Basis. The Working Group
I report concludes, inter alia, that the globally averaged surface temperatures
have increased by 0.6 ± 0.2°C over the 20th century; and that, for
the range of scenarios developed in the IPCC Special Report on Emission Scenarios
(SRES), the globally averaged surface air temperature is projected by models
to warm 1.4 to 5.8°C by 2100 relative to 1990, and globally averaged sea
level is projected by models to rise 0.09 to 0.88 m by 2100. These projections
indicate that the warming would vary by region, and be accompanied by increases
and decreases in precipitation. In addition, there would be changes in the variability
of climate, and changes in the frequency and intensity of some extreme climate
phenomena. These general features of climate change act on natural and human
systems and they set the context for the Working Group II assessment. The available
literature has not yet investigated climate change impacts, adaptation, and
vulnerability associated with the upper end of the projected range of warming.
This Summary for Policymakers, which was approved by
IPCC member governments in Geneva in February 2001, describes the current state
of understanding of the impacts, adaptation, and vulnerability to climate change
and their uncertainties. Further details can be found in the underlying report.
Section 2 of the Summary presents a number of general
findings that emerge from integration of information across the full report.
Each of these findings addresses a different dimension of climate change impacts,
adaptation, and vulnerability, and no one dimension is paramount. Section
3 presents findings regarding individual natural and human systems, and
Section 4 highlights some of the issues of concern for
different regions of the world. Section 5 identifies priority
research areas to further advance understanding of the potential consequences
of and adaptation to climate change.