The 5th IPCC-Assessment Report shows that climate change and its causes have been understood, yet many questions remain unanswered. More climate research and a more rigorous accumulation and analysis of climate data are needed.
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.
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.