With the UN climate summit to start in Azerbaijan in a week, here is a recap of 10 key dates in the battle against global warming. Alerted by scientists to signs that the Earth's surface is warming, the United Nations in 1988 establishes the Intergovernmental Panel on Climate Change (IPCC) to investigate. Two years later, the panel reports that heat-trapping "greenhouse" gases generated by human activity are on the rise and could intensify planetary warming.
In a series of studies, evidence accumulates that human activities -- the burning of coal, oil and gas; logging of rainforests and destructive farming practices -- are heating the Earth's surface, a prelude to disruptions of its climate system. A 1992 "Earth Summit" in Rio de Janeiro, Brazil, creates the UN Framework Convention on Climate Change (UNFCCC), with the aim of reducing greenhouse gas emissions. Since 1995, so-called "Conferences of the Parties", or COPs, have been meeting to pursue that elusive goal.
In 1997, nations agree in Kyoto, Japan, on a 2008-2012 timeframe for industrialised nations to reduce greenhouse gas emissions by an average of 5.2 percent from 1990 levels. Developing countries, including China, India and Brazil, are not required to take on binding targets.
But in 2001, the United States, at the time the world's biggest carbon emitter, refuses to ratify the protocol, which takes effect in 2005. The IPCC reports in 2007 that evidence of global warming is now "unequivocal" and extreme weather events.
