WHEN the tobacco industry was feeling the heat from scientists who showed that smoking caused cancer, it took decisive action.

It engaged in a decades-long public relations campaign to undermine the medical research and discredit the scientists. The aim was not to prove tobacco harmless but to cast doubt on the science.

In May this year, the multibillion-dollar oil giant Exxon-Mobil acknowledged that it had been doing something similar. It announced that it would cease funding nine groups that had fuelled a global campaign to deny climate change.

Exxon's decision comes after a shareholder revolt by members of the Rockefeller family and big superannuation funds to get the oil giant to take climate change more seriously. Exxon (once Standard Oil) was founded by the legendary John D. Rockefeller. Last year, the chairman of the US House of Representatives oversight committee on science and technology, Brad Miller, said Exxon's support for sceptics "appears to be an effort to distort public discussion".

The funding of an array of think tanks and institutes that house climate sceptics and deniers also worried Britain's premier scientific body, the Royal Society. It found that in 2005 Exxon distributed nearly $3 million to 39 groups that "misrepresented the science of climate change by outright denial of the evidence that greenhouse gases are driving climate change". It asked Exxon to stop the funding and its protests helped force Exxon's recent retreat.