They aim to compensate for unavoidable CO2 emissions by avoiding emissions elsewhere or preserving carbon sinks. Critics question whether they benefit the climate.

In the 2015 Paris Climate Agreement, the signatory states pledged to balance the emission and removal of greenhouse gases by 2050. This means that human activities only release as many greenhouse gases as can be removed from the atmosphere by natural or technical means. This is the balance referred to by the terms carbon neutrality, greenhouse gas neutrality and climate neutrality.

A central question posed by climate research is how much warmer it will become on Earth if the concentration of greenhouse gases increases by a certain amount. One measuring rod for this is called climate sensitivity. In the following, we explain what this term means.

Thick and extended masses of ice on land are called ice sheets. They form when the pressure of gradually accumulating snow transforms the underlying layers into ice. Thick and extended masses of ice on land are called ice sheets. They form when the pressure of gradually accumulating snow transforms the underlying layers into ice.

Permafrost is frozen soil whose temperature stays below freezing (0°C) for at least two consecutive years. It forms about 15 percent of the land surface in the Northern Hemisphere and 10 percent of the Earth’s surface. Permafrost regions include the Arctic and some parts of the Antarctic. Mainly, permafrost is found in the Siberian tundra and parts of Alaska, but also at high elevations such as Germany’s highest mountain, the Zugspitze.

Permafrost is frozen soil with temperatures that stay below freezing point (0°C) for at least two consecutive years. It forms about 15 percent of the land surface in the Northern Hemisphere and can also be found in the Antarctic and at high elevations in mountain ranges. It can include stone, sediment or soil and contains various amounts of ice.

Along with wind, the sun is one of Germany's most important sources of renewable energy. Solar cells convert incoming sunlight into electric current. So far, modules comprising multiple solar cells have mainly been installed on the roofs of buildings or in large open spaces. But now, solar modules can also be integrated into the facades of buildings or in other parts of building envelopes.

Mangrove forests can mitigate climate change by binding large amounts of CO2 in their wood and sediment over long periods. To express it in technical jargon, they produce “negative emissions.”

Seagrasses are marine plants that live in coastal waters of all continents, except Antarctica. If seagrass meadows would be restored or newly planted, they could help tackle climate change. This is a nature-based solution to revert CO2 emissions, a so-called ‘negative emission technology‘.