The Intergovernmental Panel on Climate Change (IPCC) regularly summarises the current state of knowledge on climate change in an assessment report, providing politicians and the public with scientific information and the basis for policy decision-making on climate change mitigation and adaptation. MeteoSwiss is involved in the report.
The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP). The IPCC is an intergovernmental and scientific body that summarises the current state of knowledge on climate change about every six years in an assessment report and evaluates it from a scientific perspective. The IPCC does not conduct its own scientific research, but relies on widely acknowledged and peer-reviewed publications. As the Intergovernmental Panel on Climate Change, it provides the basis for science-based policy decisions and identifies options for action, but does not prescribe any particular policy.
An IPCC Assessment Report is organized in three parts, which are published at intervals of several months. Each volume is assigned to a Working Group (WG).
Assessment Reports also include a Summary for Policymakers (SPM), which is prepared for each volume. The IPCC member states and the scientific community discuss the SPM in a plenary session line by line in days of negotiations. Governments can request for a different wording and make suggestions for changes. However, the scientific statements of the report remain unchanged.
The preparation and approval process is the same for all three volumes of the IPCC (Fig. 1).
In a first step, the scientific community, political decision-makers and others define concrete topics and the structure of the report. For each chapter, a team of authors is assembled, selected on the basis of their expertise. The composition of the author teams also aims to reflect a range of disciplines and backgrounds.
In the actual writing process, the authors use already published findings, if possible from scientific journals, compile them and evaluate them. The drafts then go through a multi-stage review process. The first draft of the report is reviewed by scientific experts; the second draft is additionally reviewed by government representatives of the member states. The respective authors must give due consideration to any comment or criticism and justify changes in writing.
The final draft is turned into a Summary for Policymakers (SPM), which is discussed sentence by sentence by the scientific community and IPCC member states during a multi-day plenary session. The aim of the summary is to express the complicated interrelations in a clear and understandable way. However, wording may only be changed by the governments if the statement is covered by the report, so that scientific correctness remains ensured. With the formal approval of the Assessment Report and the Summary for Policymakers, the member states officially recognize the scientific statements of the IPCC.
As an IPCC member state, Switzerland is part of the plenary session. The Federal Office for the Environment (FOEN) heads the Swiss delegation.
The role of MeteoSwiss is to provide the Swiss delegation with scientific information on the physical basis of climate change. Accordingly, MeteoSwiss is also involved in the review of the Summary for Policymakers. Especially the results of the Physical Science Basis of Climate Change (Working Group I) are closely linked to the activities at the national weather services. Among other things, this report presents the current state of knowledge on past, present and future climate at global and regional scale.
In addition, MeteoSwiss fulfils an important role in the IPCC process through its research in the field of climate and climate change and its scientific contributions to the report.