Développement durable et efficacité énergétique

New research takes the deepest dive ever into historic climate records.

Back in 1999 Penn State climate scientist Michael Mann released the climate change movement's most potent symbol: The "hockey stick," a line graph of global temperature over the last 1,500 years that shows an unmistakable, massive uptick in the twentieth century when humans began to dump large amounts of greenhouse gases into the atmosphere. It's among the most compelling bits of proof out there that human beings are behind global warming, and as such has become a target on Mann's back for climate denialists looking to draw a bead on scientists.

Now it's gotten a makeover: A study published in Science reconstructs global temperatures further back than ever before -- a full 11,300 years. The new analysis finds that the only problem with Mann's hockey stick was that its handle was about 9,000 years too short...