This depends on which region you are in. In many areas where it is already hot and dry, for example, these trends will intensify. In rather cool regions, warmer temperatures will lead to a shift in growing seasons. The Intergovernmental Panel on Climate Change also made it quite clear in its latest Working Group I Assessment Report that the likelihood and intensity of extreme weather events such as drought and heat waves have already increased compared to pre-industrial times - with impacts such as crop failures, increased risk of fires, but also flooding. As a result of a warmer climate, vegetation boundaries are shifting northward, for example. In general, warm-adapted plants and animals are expected to migrate with the climate. The latter does not always succeed, as obstacles such as mountains or even urban spaces stand in the way. Furthermore, a new habitat is of course not only defined by the right temperature, but many factors have to interact.

Land use is a massive source of greenhouse gas emissions. Through CO₂ release, for example, when forests, savannahs or moors are converted into agricultural land, but also through methane release from rice cultivation and livestock farming and through nitrous oxide emissions from fertilizer use. At the same time, however, forests also absorb CO₂ from the atmosphere. In the latest report of the Intergovernmental Panel on Climate Change, the AFOLU sector (agriculture, forestry and other land use) is estimated to account for 22% of anthropogenic greenhouse gas emissions.

Climate change and land use change are indeed closely related and intertwined with all sustainability goals. Understanding the very complex interactions requires a wide variety of methods from different scientific communities. Direct measurements, for example, to quantify greenhouse gas sources or sinks and to identify how climate and land management are affected. Satellite-based observations are also becoming increasingly important, both in terms of measuring greenhouse gas concentrations, but also to better quantify land use changes. And, of course, we use a wide variety of model calculations, which, on the one hand, help to achieve global estimates, since field measurements simply cannot be made all over the world, but which can also be used to project into the future. And finally, it is also necessary to link results from natural science methodology with those from the social sciences and economics.

It is difficult to predict how the carbon cycle in terrestrial ecosystems will change. Warming or drought often leads to a decrease in CO₂ fixation in plants, and warming to increased release from soils or peatlands. Current CO2 sinks may well become CO₂ sources. However, the increase in CO₂ in the atmosphere also leads to an increase in photosynthesis and increased growth. However, we simply do not know yet whether this will continue to be the case, because other factors, such as the nutrient content of the soil, also play a role here. The current situation is that the world's terrestrial ecosystems remove almost 30% of total anthropogenic CO₂ emissions from the atmosphere each year, thus substantially mitigating climate change A very important aspect is therefore to preserve existing sinks as much as possible - in other words, to stop further deforestation and destruction of savannahs and wetlands as soon as possible. Ways must also be found to restore ecosystems without conflicting with other sustainability goals such as food production. This adds great value to biodiversity goals and many other positive spin-offs for human society. Most importantly, we need to get serious about reducing emissions. Planting trees is good - but it will not save the climate.

There are many, but they have to fit together well. This is where politics, above all, is called upon. Today, subsidies are still misdirected in many areas. Agricultural policy, climate policy and environmental protection are often found in different departments. For me as a voter, the thought keeps coming up that these may not always be optimally coordinated. There are simply too many of us on this planet, and a small number of us consume far too much per capita. One person alone cannot solve the problems of this world; this is where politics is really needed.

Interview: Beatrix Boldt