There is strong evidence that the warming of the Earth over the last half-century has been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation. The size of future temperature increases and other aspects of climate change, especially at the regional scale, are still subject to uncertainty. Nevertheless, the risks associated with some of these changes are substantial. It is important that decision makers have access to climate science of the highest quality, and can take account of its findings in formulating appropriate responses.
In view of the ongoing public and political debates about climate
change, the aim of this document is to summarise the current
scientific evidence on climate change and its drivers. It lays out
clearly where the science is well established, where there is wide
consensus but continuing debate, and where there remains substantial
uncertainty. The impacts of climate change, as distinct from the
causes, are not considered here. This document draws upon recent
evidence and builds on the Fourth Assessment Report of Working Group I
of the Intergovernmental Panel on Climate Change (IPCC), published in
2007, which is the most comprehensive source of climate science and
its uncertainties.
Climate change report.