The Intergovernmental Panel on Climate Change (IPCC) was
jointly established by the World Meteorological Organization
(WMO) and the United Nations Environment Programme
(UNEP) to assess the scientific, technical and socio-economic
information relevant for the understanding of the risk of
human-induced climate change. Since its inception the IPCC
has produced a series of comprehensive Assessment Reports on
the state of understanding of causes of climate change, its
potential impacts and options for response strategies. It
prepared also Special Reports, Technical Papers, methodologies and guidelines. These IPCC publications have become
standard work of reference, widely used by policymakers,
scientists and other experts.
In 1992 the IPCC released emission scenarios to be used for
driving global circulation models to develop climate change
scenarios. The so-called IS92 scenarios were pathbreaking.
They were the first global scenarios to provide estimates for the
full suite of greenhouse gases. Much has changed since then in
our understanding of possible future greenhouse gas emissions
and climate change. Therefore the IPCC decided in 1996 to
develop a new set of emissions scenarios which will provide
input to the IPCC Third Assessment Report but can be of
broader use than the IS92 scenarios. The new scenarios provide
also input for evaluating climatic and environmental consequences of future greenhouse gas emissions and for assessing
alternative mitigation and adaptation strategies. They include
improved emission baselines and latest information on
economic restructuring throughout the world, examine different rates and trends in technological change and expand the
range of different economic-development pathways, including
narrowing of the income gap between developed and developing countries. To achieve this a new approach was adopted to
take into account a wide range of scientific perspectives, and
interactions between regions and sectors. Through the
so-called “open process” input and feedback from a community of experts much broader than the writing team were
solicited. The results of this work show that different social,
economic and technological developments have a strong
impact on emission trends, without assuming explicit climate
policy interventions. The new scenarios provide also important
insights about the interlinkages between environmental quality
and development choices and will certainly be a useful tool for
experts and decision makers.
As usual in the IPCC, success in producing this Report has
depended first and foremost on the cooperation of scientists and
other experts worldwide. In the case of this Report the active
contribution of a broad expert community to the open process
was an important element of the success. These individuals have
devoted enormous time and effort to producing this Report and
we are extremely grateful for their commitment to the IPCC
process. We would like to highlight in particular the enthusiasm
and tireless efforts of the Coordinating Lead Author for this
report, Nebojs˘a Nakic´enovic´ and his team at the International
Institute for Applied Systems Analysis (IIASA) in Laxenburg,
Austria, who ensured the high quality of this Report.
Further, we would like to express our sincere thanks to:
• Robert T. Watson, the Chairman of the IPCC;
• The Co-chairs of Working Group III, Bert Metz and
Ogunlade Davidson;
• The members of the writing team;
• The staff of the Working Group III Technical Support Unit,
including Robert Swart, Jiahua Pan, Tom Kram and Anita
Meier;
• N. Sundararaman, Secretary of the IPCC, Renate Christ,