Global climate change is largely considered to be today’s most serious environmental problem. Experts meanwhile agree that there will be a climate change in the long run and that it will at least to a certain extent result from man-made emissions of greenhouse gases.

The most important climate gas is carbon dioxide (CO₂), which is estimated to account for 60 percent of the man-made climate change. Climate gases allow sunlight to enter the atmosphere freely as shortwave radiation; when it strikes the surface of the earth, some of it is reflected back towards space in the form of long wave radiation and partially absorbed by climate gases. This greenhouse effect leads to global warming.

During the 20^th century, the average global temperature already increased by about 0.6 degrees Celsius. Recent scientific findings leave no doubt that this increase exceeds the natural fluctuations of the global temperature during the second millennium. At the same time, the CO₂ concentration in the atmosphere has risen by 31 percent since 1750. This can primarily be ascribed to CO₂ emissions from burning fossil fuels. With the present concentration of 367 ppm (parts per million) there is more carbon dioxide in the atmosphere than at any point of time during the last 420,000 years, as per a report by the Intergovernmental Panel on Climate Change (IPCC).

The IPCC is an intergovernmental organisation established in 1988. Research findings from various disciplines on climate change are compiled by the IPCC and published in the IPCC Assessment Reports. Due to the large number of researchers involved, the IPCC reports are widely regarded as presentations of state-of-the-art knowledge of climate-change.

With the aim to avoid climate change, 189 countries have agreed upon the United Nations Framework Convention on Climate Change (UNFCCC). It was adopted in Rio de Janeiro in 1992 and entered into force in 1994. Under the convention, all member states are obligated to design strategies for the reduction of climate gas emissions and to report activities undertaken in regular intervals.

The Framework Convention on Climate Change provides the basis for the Kyoto Protocol which assigns mandatory targets for the reduction of greenhouse gas emissions to the signatory nations. The Protocol aims at reducing the collective emissions of climate gases by 5.2 percent compared to the year 1990 over the five-year period of 2008-12. In this context, the European Union has committed itself to a reduction of climate gas emissions by 8 percent. Germany’s national target is 21 percent. The website Climate Policy Map shows how the most important countries deal with this topic.

Apart from these efforts to reduce climate gas emissions, the need for adaptation strategies to better cope with the impending consequences of climate change has become widely recognized.