Could Aggressive Climate Targets Backfire?

For the past several years, international climate diplomacy has been focused on cutting greenhouse gas emissions deeply enough to keep global temperatures from rising by more than two degrees centigrade.  In private, many experts and diplomats have acknowledged that that goal might be unrealistic. In public, though, pretty much everyone presented a more optimistic face.

At the Singapore Energy Summit earlier this week, I was struck by how many people, experts and officials alike, were much more willing to publically challenge the viability of the two-degree target than they have been in the past. Nobuo Tanaka, until recently the head of the International Energy Agency (IEA), made a particularly arresting claim: with the targets we’ve been talking about increasingly looking implausible, it is time to shift more of our efforts away from mitigation (reducing emissions) and toward adaptation to climate change.

This sort of statement troubles me. There is no reason to shift sharply away from efforts to cut emissions simply because some of the most ambitious goals for doing so may be unachievable. The differences between two, four, and six degrees of warming – and even worse possibilities – are stark. Indeed, even if one (correctly) thinks that adaptation efforts are essential, it should also be clear that mitigation makes those efforts more manageable.

So why did Tanaka say what he did? I worry that this is part of the fallout from a campaign for climate action that has tried to motivate people by presenting all or nothing choices. Anyone involved in climate policy has seen the presentation a thousand times: someone shows charts of what world temperatures, sea levels, and so on would look like with unabated greenhouse gas emissions; then they show similar charts for a world where we keep global temperatures from rising by more than two degrees. Think that the former case is too ugly to contemplate? (It is.) Think that the latter one looks a heck of a lot better? (It does.) Then you need to adopt the program of massive emissions cuts that’s necessary to realize it.

That’s fine if it succeeds in rallying the world to those big emissions cuts. But it risks sending some people a second, incorrect, message: if you think that it’s impossible to achieve the “good” outcome, you better resign yourself to the awful one.

Of course, in reality, there’s a large middle ground that sees substantial emissions cuts, nonetheless fails to keep temperature rises to two degrees, but still keeps the world well away from the worst-case outcomes. (One can debate whether it’s actually possible to stabilize at certain intermediate levels of greenhouse gas concentrations, given the possibility of large carbon-cycle feedbacks, but that’s a largely separable issue.) And the sorts of policies best suited to achieving these intermediate outcomes may not just be “failed” versions of those policies that one might pursue in order to reach the more ambitious ones. There are policy steps that may seem inadequate – even useless – when measured against the toughest targets, but that suddenly look quite useful when the goals are more modest.

This isn’t a brief for low ambition, but it is a big caution. By presenting climate policy as an all-or-nothing choice, advocates of strong climate action seem to believe they’ll maximize their odds of absolute success.  That may be true, but it increasingly looks like they’re also maximizing their odds of absolute failure.