Working
Group II Contribution to the Intergovernmental Panel
on Climate Change
Fourth Assessment Report
Climate Change 2007:
Climate Change Impacts, Adaptation and Vulnerability
This Summary sets
out the key policy-relevant findings of the Fourth
Assessment of Working Group II of the Intergovernmental
Panel on Climate Change (IPCC).
The Assessment is
of current scientific understanding of impacts of
climate change on natural, managed and human systems,
the capacity of these systems to adapt and their vulnerability.
It builds upon past IPCC assessments and incorporates
new knowledge gained since the Third Assessment.
Statements in this
Summary are based on chapters in the Assessment and
principal sources are given at the end of each paragraph.
The Working Group I contribution to the IPCC Fourth
Assessment Report describes progress in understanding
of the human and natural drivers of climate change1,
observed climate change, climate processes and attribution,
and estimates of projected future climate change.
It builds upon past IPCC
assessments and incorporates new findings from the
past six years of research.
Scientific progress since the TAR is based upon large
amounts of new and more comprehensive data, more sophisticated
analyses of data, improvements in understanding of
processes and their simulation in models, and more
extensive
exploration of uncertainty ranges.
The basis for substantive paragraphs in this Summary
for Policymakers can be found in the chapter sections
specified in curly brackets.
