If CO2 both cools and warms the planet, this means that climatologists have no idea what’s going on.
Major theories about what causes temperatures to rise have been thrown into doubt after NASA found the Earth has cooled in areas of heavy industrialisation where more trees have been lost and more fossil fuel burning takes place.
Environmentalists have long argued the burning of fossil fuels in power stations and for other uses is responsible for global warming and predicted temperature increases because of the high levels of carbon dioxide produced – which causes the global greenhouse effect.
While the findings did not dispute the effects of carbon dioxide on global warming, they found aerosols – also given off by burning fossil fuels – actually cool the local environment, at least temporarily.
The research was carried out to see if current climate change models for calculating future temperatures were taking into account all factors and were accurate.
A NASA spokesman said: “To quantify climate change, researchers need to know the Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS) of Earth.