The 1980s turn out to be the warmest decade, with seven of the eight warmest years recorded up to 1990. Meeting of climate scientists in Toronto subsequently calls for 20 per cent cuts in global CO 2 emissions by the year 2005. IPCC warns that only strong measures to halt rising greenhouse gas emissions will prevent serious global warming. Provides scientific clout for UN negotiations for a climate convention. Mount Pinatubo erupts in the Philippines, throwing debris into the stratosphere that shields the Earth from solar energy, which helps interrupt the warming trend.
Average temperatures drop for two years before rising again.
Hottest year yet. In March, the Berlin Mandate is agreed by signatories at the first full meeting of the Climate Change Convention in Berlin. The meeting also adopts a series of flexibility measures, allowing countries to meet their targets partly by trading emissions permits, establishing carbon sinks such as forests to soak up emissions, and by investing in other countries. The precise rules are left for further negotiations. Series of major floods around the world reinforce fears that global warming is raising the risk of extreme weather events.