The idea that the world can stay below +2° C looks increasingly delusional [View all]

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http://www.vox.com/2014/4/22/5551004/two-degrees

Two decades later, there’s just one huge problem with this picture. The idea that the world can stay below 2°C looks increasingly delusional.

Consider: the Earth’s average temperature has already risen 0.8°C since the 19th century. And if you look at the current rapid rise in global greenhouse-gas emissions, we’ll likely put enough carbon dioxide in the atmosphere by mid-century to surpass the 2°C limit — and soar past the 4°C limit by century's end. That’s well above anything once deemed "dangerous." Getting back on track for 2°C would, at this point, entail the sort of drastic emissions cuts usually associated with economic calamities, like the collapse of the Soviet Union or the 2008 financial crisis. And we’d have to repeat those cuts for decades.

The climate community has been slow to concede defeat. Back in 2007, the UN's Intergovernmental Panel on Climate Change published a report noting that the world could stay below 2°C — but only if we started cutting emissions immediately. The years passed, countries did little, and emissions kept rising. So, just this month, the IPCC put out a new report saying, OK, not great, but we can still stay under 2°C. We just need to cut more drastically — oh, and also figure out a way to pull lots of carbon dioxide back out of the atmosphere. (Never mind that we still don’t have the technology to do the latter.)

We're on track for 4°C of global warming — and 2°C is increasingly unlikely

Predicted temperature increases under various emissions scenarios:


"At some point, scientists will have to declare that it’s game over for the 2°C target," says Oliver Geden, a climate policy analyst at the German Institute for International and Security Affairs. "But they haven’t yet. Because nobody knows what will happen if they call this thing off." The 2°C target was one of the few things that everyone at global climate talks could agree on. If the goal turns out to be impossible, the worry goes, countries might just stop trying altogether.