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If you’ll forgive me for stating the obvious: Most people don’t understand climate change very well. This includes a large proportion of the nation’s politicians, journalists, and pundits — even the pundits who write about it. (I’m looking at you, Joe Nocera.)
One reason for the widespread misunderstanding is that climate change has been culturally coded as an “environmental problem.” This has been, in all sorts of ways, a disaster. Lots of pundits, especially brain-dead “centrist” pundits, have simply transferred their framing and conception of environmental problems to climate. They approach it as just another air pollution problem.
However, there are two features of climate change that make it importantly different from other environmental problems, not just in degree but in kind. And these differences have important public policy implications.
The first difference is thatcarbon dioxide is not like other pollutants.
To make this clear, let’s use the old bathtub analogy. The faucet is the source of the pollutant. The tub is the environment. And the drain represents the means by which the pollutant exits the environment. The key fact to remember: The damage to public health is determined by the total amount of pollutant in the tub.
Take a familiar air pollutant like particulate matter. We are spewing it into the air from tailpipes and smokestacks (the faucet). It leaves the air through simple gravity (the drain). Most of it falls to earth in days or weeks.
So when it comes to the particulate-matter bathtub, the drain is very large. We can reduce the total level of particulate matter in the tub any time we want; all we have to do is turn the faucet down, or off, and the tub will drain rapidly.
Carbon dioxide is not like that. Once it’s in the tub, it stays there for up to 100 years before it drains out. And the drain in the bathtub (so-called “sinks” that absorb carbon out of the air, like oceans and forests) is comparatively small relative to the enormous amounts coming out of the faucet. And by the way, we’re actively making the drain smaller by cutting down forests and carbon-loading the oceans.
This makes for a very different situation. Even if we cut our emissions by a third tomorrow, we would still be increasing the total amount in the bathtub:
The typical climate-policy targets that get thrown around — reducing emission rates by 80 percent by 2050, for example — are relatively meaningless. They focus on the rate of flow from the faucet. But that’s not what matters. What matters is the amount in the tub. If the tub fills up enough, global average temperature will rise more than 2 degrees C and we’ll be in trouble. Avoiding that — staying within our “carbon budget” — is the name of the game.
The public-policy implications are straightforward: Because CO2 is slow to drain, and the damages are cumulative, we need to reduce the amount of CO2 we’re spewing out of the faucet now, as much as possible, as quickly as possible. Yes, we’ll need new technologies and techniques to drive emissions down near to zero, and we should R&D the hell out of them. But we absolutely cannot afford to wait. There is no benign neglect possible here. Neglect is malign.
The second difference is that climate change is irreversible.
As Joe Romm notes in a recent post, New York Times columnist Joe Nocera slipped up in his latest column and referred to technology that would “help reverse climate change.” I don’t know whether that reflects Nocera’s ignorance or just a slip of the pen, but I do think it captures the way many people subconsciously think about climate change. If we heat the planet up too much, we’ll just fix it! We’ll turn the temperature back down. We’ll get around to it once the market has delivered economically ideal solutions. More
