We May Have Just Bought Ourselves an Extra Decade to Avoid Catastrophic Climate Change - by Joe Romm

The world appears to have bought itself a little time in the fight to avoid climate catastrophe, according to a new analysis.

Virtually every major country has made pledges to limit or reduce carbon pollution in advance of the Paris climate talks this December.  These pledges generally end in 2025 or 2030, and so they only matter if the world keeps ratcheting down its greenhouse gas emissions in future agreements until we get near zero by century’s end.  Otherwise we will blow past the 2°C line of defense against very dangerous-to-catastrophic global warming, and hit 3.6°C warming by 2100.

That’s the key finding of a new analysis from Climate Interactive and the MIT Sloan School of Business, tallying up the global pledges to limit carbon pollution leading up to the big Paris climate talks later this year.

Those pledges, called intended nationally determined contributions (INDCs), include the European Union cutting total emissions 40 percent below 1990 levels by 2030, the U.S. cutting net greenhouse gas emissions emissions 26 to 28 percent below 2005 levels by 2025 (including land use change and forestry), and China’s peaking in CO2 by 2030.

The good news, as you can see, is that the INDCs have bought us another five to 10 years of staying close to the 2°C path.  I asked Andrew Jones, one of the systems-thinking savants behind Climate Interactive, if that was correct and he said, “Yep, about seven years.”  By “staying close” I mean staying close enough to the 2°C path that it remains plausibly achievable — though (obviously) politically still very, very challenging.

Of course, like all emissions models, the Climate Interactive model makes assumptions about what is a plausibly achievable 2°C path given how long we have delayed acting.  And that involves deciding how fast the world could plausibly cut its greenhouse gas emissions each year — sustained for many decades.  They use 3.5 to 4 percent a year.  That is mostly a political-economic judgment, since there is no real way of knowing how fast humanity could act once we become truly desperate to avoid multiple simultaneous catastrophes that are irreversible on a timescale of many centuries.

The point is that a successful outcome of Paris will not “solve the climate problem” and indeed won’t give us a 2°C world, as anyone who is paying attention understands.  (Sadly, a lot of folks in the media aren’t paying attention.)
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Still, this would be an important accomplishment — and one that mirrors the incremental approach the world took to save the ozone layer.  As NASA’s Gavin Schmidt told the New York Times, “By the time people get 10, 15 years of actually trying to do something, that’s going to lead to greater expertise, better technology, more experience.”  Schmidt, who heads the same climate team James Hansen once did, added, “People will then say, ‘Oh, you know what?  We can commit to do more.’”

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