In the late 1970s, scientists first came to a consensus that global warming was likely to result from increasing greenhouse gases released by the burning of fossil fuels. This idea had been around since the turn of the century, but the development of computer models made it possible to make quantitative predictions. Almost immediately, a small group of politically connected and conservative scientists began to question this consensus. As empirical scientific data mounted up, their attacks became more unprincipled. These conservative scientists used data selectively and often misrepresented the conclusions of many studies undertaken by the scientific community.
In 1992, world leaders gathered in Rio de Janeiro to sign the United Nations Framework on Climate Change. President George W Bush promised to translate the written document into “concrete action”. Three years later, the Intergovernmental Panel on Climate Change (IPCC) declared that the human impact on the earth’s climate was no longer a prediction but an observable fact.