The Corner

Energy & Environment

The Two-Degree Target

Three polar bears are seen on the Beaufort Sea coast within the 1002 Area of the Arctic National Wildlife Refuge (U.S. Fish and Wildlife Service Alaska Image Library)

If you’ve followed debates over climate policy, you’ve no doubt heart of the two-degree target, based on the widely-held belief that governments around the world should endeavor to limit global warming to two degrees Celsius above the levels that prevailed in the preindustrial era. But what if undue reverence for the two-degree target hurts legitimate efforts to address climate change?

“Forty years after it was first proposed, the two-degree target continues to maintain a talismanic hold over global efforts to address climate change,” writes the Breakthrough Institute’s Ted Nordhaus for Foreign Affairs, “despite the fact that virtually all sober analyses conclude that the target is now unobtainable.” And even if we could stay within that limit, Nordhaus writes, there is no proof that doing so would ensure that the world would avoid catastrophe. Nor can we be certain that crossing the line would lead to disaster.

What we can be sure of is that “on a planet that is almost certainly going to be much hotter even if the world cuts emissions rapidly,” Nordhaus writes, “the continuing insistence that human societies might cut emissions rapidly enough to avoid dangerous climate change risks undermining the urgency to adapt.” In the developing world, for example, adaptation will need to come in the form of infrastructure — strong housing, better transportation, and so on — that makes populations more resilient to climate disasters. And building that kind of infrastructure comes with a carbon price tag, something governments are less able to pay when the two-degree target and related carbon budgets have been enshrined by development organizations that would otherwise lend them the money.

The two-degree target can also undermine efforts to incrementally cut carbon on the grounds that nothing short of full decarbonization will allow humanity to avoid disaster. For example, the switch from coal to natural gas was an important route a lower-carbon economy in the United States. And the development of next-generation nuclear technology, advanced geothermal, and carbon-capture technologies are still worthy pursuits, even though they won’t come online on a large scale soon enough to keep warming at two degrees Celsius.

“From its earliest days, climate policy and advocacy has always been predicated, sometimes explicitly and always implicitly, on the idea that climate change was a problem that could be solved. The two-degree threshold is a reflection of that impulse,” Nordhaus concludes. “In reality, climate change is now a permanent condition of the human present and future, one that we will manage more or less successfully but that we will never solve. Liberating international climate policy efforts from the various constraints that the two-degree threshold imposes can’t eliminate all of the risks that climate change will bring. But doing so might allow us to manage them better.”

(I should note that I know Ted Nordhaus, and though I’m sure I disagree with him and his team on many issues, I’m a fan of the Breakthrough Institute’s work and a member of its board.)


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