[Illustrations, footnotes and references available in PDF version]
"The concept of dangerous climate change, although central to the UN’s Framework Convention on Climate Change and its Kyoto Protocol to restrict CO2 emissions, has never been formally defined. A general understanding has evolved within scientific and political discussions on the issue that global warming exceeding 2oC would indeed be dangerous. Some scientists go so far as to suggest that 2oC represents a ‘tipping point’ beyond which ‘runaway global warming’ is likely. The evidence, however, is speculative and linked to the projections of computer models."