Introduction
Introduction
This year marks the 100th anniversary of the discovery of the greenhouse effect by the Swedish chemist Svante Arrhenius. Thanks to sophisticated computers and satellites, scientists today know more about how burning fossil fuels and other industrial activities release carbon dioxide and other gases that trap solar heat in the Earth's atmosphere. Predictions about the increasing pace of global warming caused by human activity have so alarmed policy-makers that efforts are under way to draw up an international treaty - due to be signed in Kyoto, Japan, in 1997 - to curb greenhouse gas emissions. These efforts have sparked controversy in the United States, where some scientists and industry representatives dispute the accuracy of future warming predictions and oppose limits on energy consumption.