The results of the Intergovernmental Panel on Climate Change (IPCC) are unambiguous: climate change is happening, and it is largely caused by human activities. The lower atmosphere and the oceans have warmed, glaciers, permafrost and the ice sheets are melting and sea levels are rising. This has been demonstrated through comprehensive observations and an improved understanding of the relationships that govern the climate system. The greatest disturbance to the Earth's delicate energy balance stems from the burning of coal, gas and oil. Fossil fuels and extensive deforestation are the main causes of the rising concentration of carbon dioxide in the atmosphere that has increased to levels unprecedented in the last 800,000 years at least.

The faster the rate of global warming, the severer the climate consequences will be. Even with a moderate increase in emissions, the rise in associated risks will be disproportionate. The consequences of climate change must remain manageable. In this light, all signatories to the United Nations Framework Convention on Climate Change decided to make every effort to ensure that global warming does not exceed the limit of two degrees centigrade above pre-industrial levels. If this level is crossed, the ability of humankind and nature to adapt will be jeopardized, especially in the world’s poorer regions. Higher temperatures could induce irreversible climate changes, climate researchers have warned.

Main causes of climate change recognized

Even with the publication of the Fifth IPCC Assessment Report, questions regarding climate research remain. The main causes of climate change have, however, been recognized. This provides the basis for elaborating strategies to address climate change and sustainable development across national borders and disciplinary boundaries.

• We must bridge the gap between short-term weather forecasts and long-term climate change projections. In order to enable medium-term climate predictions for specific regions, the German Federal Ministry of Education and Research (BMBF) is funding projects which aim to create a climate modelling system that can deliver reliable climate predictions for shorter time scales.
• As climate change cannot be completely avoided, even with the most ambitious climate change mitigation programmes, we need to know more about effective adaptation methods. The BMBF has a number of programmes in place which are developing methods and strategies that will help specific regions, cities and communities to prepare for climate change.
• The challenge of adapting to climate change is especially important in emerging and developing countries, as they are often most vulnerable to the impacts of heat, storms and earthquakes. In addition to their vulnerability, developing countries are often also limited by their research capacities. Cooperative projects are, therefore, designed to support scientists locally, helping them to develop and expand their ability to conduct observation and evaluation projects and to develop sustainable solutions.
• Unabated climate change will entail high economic costs. Investments made now to mitigate global warming will therefore lower the overall costs in the long term. Measures to determine the criteria for a climate policy committed to the two-degree-limit will require robust and practical approaches to estimating the costs, risks and opportunities of climate change mitigation and adaptation options.