Next week's climate change conference in Kyoto is expected to be the most high-profile environmental gathering since the 1992 Earth Summit in Rio de Janeiro. The stated goal is to accelerate the pace of international action to deal with climate change by way of developed countries adopting legally-binding targets and timetables to reduce greenhouse gas emissions.
Kyoto marks the culmination of a series of conferences under the UN Framework Convention on Climate Change, which was opened for signature in Rio and has since been ratified by almost 170 countries.
The earlier conferences of the parties to the convention were held in Berlin (1995), Geneva (1996) and Bonn last October to pave the way for a protocol on greenhouse gas reductions to be adopted in Kyoto.
It is 27 years since a UN report first referred to the potential for a "a catastrophic warming effect" in the atmosphere, though nobody paid much attention.
In 1988, the World Meteorological Organisation and the UN Environment Programme established a panel of scientists - the Intergovernmental Panel on Climate Change - to assess the problem.
The IPCC, made up of more than 2,000 scientists, produced its first assessment report in 1990. It confirmed the scientific basis for climate change and had a powerful effect in spurring negotiations on a treaty.
In 1995, the IPCC produced its second assessment report, concluding that "the balance of evidence suggests that there is a discernible human influence on global climate" and proposing measures to mitigate it.
The scientists' assessment was endorsed by a ministerial declaration at the second conference of the parties in Geneva, which said it should form the basis for "urgently strengthening action" on global warming.
The issue remaining to be decided in Kyoto revolves around the precise targets and timetables which the developed countries are prepared to adopt to reduce the greenhouse gas emissions causing climate change.