Second progress report by the IPCC

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The Second Assessment Report of the IPCC (English: Second Assessment Report SAR) was in December 1995 by the Intergovernmental Panel on Climate Change ( Intergovernmental Panel on Climate Change published, IPCC) report that the then available scientific findings on climate change summarized. It was the second report of the body, which, on behalf of the United Nations, is to assess the risks of current climate change and identify strategies for avoiding them. It was replaced by the Third Assessment Report (TAR) in 2001 . The report does not contain any of its own research results, but rather summarizes findings from existing scientific publications that have already been subject to peer review .

Content and structure of the report

The report confirmed the fundamental findings of the previous First Assessment Report from 1990. These included, among other things, that humans significantly change the composition of the atmosphere through their emission of greenhouse gases and thus intervene in the natural greenhouse effect of the earth, so that the global mean temperature changes the earth is warming and this trend will continue in the coming decades due to the ongoing emission of greenhouse gases. Since the trend is superimposed by natural temporal and regional fluctuations, no continuous warming is to be expected from year to year.

The second assessment report entitled Climate Change 1995 was divided into four main parts:

• the synthesis report, which summarizes the essential scientific findings that are relevant for Article 2 of the United Nations Framework Convention on Climate Change .
• the report of the IPCC Working Group I, which deals with the scientific basis of climate change.
• the report of the IPCC Working Group II, which describes the impacts , adaptation and vulnerabilities related to climate change.
• the report of the IPCC Working Group III, in which the economic and social dimensions of climate change are examined.

The reports of the respective working groups each contain a summary for political decision-makers, who summarize the several hundred pages of sub-reports in their essential findings. The synthesis report and the summaries were published in the six official UN languages ​​Arabic, Chinese, English, French, Russian and Spanish, the detailed partial reports only in English.

Progress on the previous report

In order to improve the projections of future development, the previous four emission scenarios (AD) of the First Assessment Report have been restructured and replaced by six new scenarios (IS92a-f), which make more detailed assumptions on the emission of greenhouse gases, aerosols , population, technology and Make prosperity development. Due to improvements in the understanding of the carbon cycle , better consideration of aerosol emissions and slightly lower assumptions about future greenhouse gas emissions, the projections for the expected temperature increase in the mean emission scenarios have been reduced by around a third to 2 ° C by the year 2100.

The report also states that the understanding of a number of subject areas has developed since the First Assessment Report. There have been significant improvements in distinguishing between natural and anthropogenic influences on the climate. Due to various uncertainties and since human influences are only slowly emerging from the noise of natural climate fluctuations, it was not yet possible to reliably quantify the human influence. There has also been advances in paleoclimatology , so the improved temperature reconstructions suggest that the 20th century was warmer than any other comparable period since 1400 AD. At that time, there was not enough paleodata available for earlier periods of time to enable a reliable determination of the global mean temperature. The further development of climate models through higher resolutions and the consideration of more and improved modeled physical processes made it possible for the models to reproduce the previous climate development more precisely and to make more reliable predictions. All the climate models used correctly predicted that night temperatures would rise more than daytime temperatures, that the warming would be greatest in regions of high northern latitudes, but that there would only be slight surface warming in the Arctic in summer.

Web links

• Overview of all status reports on the IPCC homepage
• Website of the German IPCC coordination office

Individual evidence

• Second progress report of the IPCC - synthesis report (PDF; 611 kB)
• Second progress report of the IPCC - Report of Working Group I (PDF; 53.6 MB)
• Second progress report of the IPCC - Report of Working Group II (PDF; 120 MB)
• Second progress report of the IPCC - Report of Working Group III (PDF; 44.3 MB)