The billionaire philanthropist Bill Gates is backing a group of climate scientists lobbying for geoengineering experiments. Photograph: Ted S. Warren/AP
A small group of leading climate scientists, financially supported by billionaires including Bill Gates, are lobbying governments and international bodies to back experiments into manipulating the climate on a global scale to avoid catastrophic climate change.
The scientists, who advocate geoengineering methods such as spraying millions of tonnes of reflective particles of sulphur dioxide 30 miles above earth, argue that a "plan B" for climate change will be needed if the UN and politicians cannot agree to making the necessary cuts in greenhouse gases, and say the US government and others should pay for a major programme of international research.
Solar geoengineering techniques are highly controversial: while some climate scientists believe they may prove a quick and relatively cheap way to slow global warming, others fear that when conducted in the upper atmosphere, they could irrevocably alter rainfall patterns and interfere with the earth's climate.