The prospect of a four-degree Celsius rise in global average temperatures in 50 years is alarming – but not alarmist, climate scientists now believe. Eighteen months ago, no one dared imagine humanity pushing the climate beyond an additional two degrees C of heating, but rising carbon emissions and inability to agree on cuts has meant [...]

Nasa’s James Hansen was the first to point out the perils of climate change to the US Congress. Here, he begins a heated debate with experts from around the world, from China to the threatened Maldives, and argues that our leaders must be shaken out of their complacency. But will they show enough courage at [...]

A respected British scientist has admitted that emails taken from his inbox, calling into question many of the accepted truths of global warming, were genuine. The documents appear to show scientists are holding back, or ignoring, evidence. One even suggested using a “trick” to hide a trend of falling temperatures. var showHover=false;