IPCC Second Assessment Report

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, IPCC) published report, which summarized the then available scientific evidence on climate change. It was the second report of the panel, which is assessing the risk in the current climate changes on behalf of the United Nations and identify mitigation strategies. He was replaced in 2001 by the Third Assessment Report ( TAR). The report does not own research, but it summarizes the findings of the existing scientific publications each have already been discussed and examined for themselves ( peer review ), together.

Content and structure of the report

The report confirmed the basic findings of the preceding it first progress report from the year 1990. These included that man changed significantly including through its emissions of greenhouse gases, the composition of the atmosphere and engaging as in the natural greenhouse effect of the earth, that the global mean temperature heats the earth, and this trend will continue over the next few decades by the further held greenhouse gas emissions. Since the trend is superimposed on natural time, and local fluctuations, no continuous heating of the year can be expected by year.

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

• The synthesis report, which summarizes the main scientific findings, which are the UNFCCC United Nations of relevance for Article 2.
• 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 associated with 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 policy makers, which summarize the multi-hundred pages sub reports in its 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 sub-reports in English only.

Progress to the previous report

In order to improve projections of future development, the previous four emission scenarios (AD) of the First Assessment Report was restructured and replaced by six new scenarios ( IS92a -f), the detailed assumptions about the emission of greenhouse gases, aerosols, demographic, technological and make the development of prosperity. Due to improvements in the understanding of the carbon cycle, the better consideration of aerosol emissions and slightly lower assumptions for future greenhouse gas emissions, the projections for the expected temperature increase in the average emission scenarios by about a third were lowered to 2 ° C by the year 2100.

Next is described in the report that has developed an understanding of a number of topics since the First Assessment Report. So there have been significant improvements to distinguish between natural and anthropogenic influences on the climate. However, due to various uncertainties and because the human factors slowly lift out from the noise of natural climate fluctuations, it was not possible to quantify the human influence reliably. In the field of paleoclimatology there has been progress, so that the improved temperature reconstructions suggest that the 20th century was warmer than any comparable period since the year 1400 AD. About earlier periods were at that time not yet enough palaeodata steps to enable a reliable determination of the global mean temperature. The development of climate models with higher resolutions and consideration of more and improved the modeled physical processes, enabled the models more accurately replicate the existing climate change and to meet more reliable predictions. So said all the climate models used correctly predicted that night temperatures will warm more than daytime temperatures that warming will be strongest in regions of high northern latitudes, but it will come only to a slight surface warming in the Arctic in summer.