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Climate change mitigation versus adaptation

There are two big sets of actions people can take as rational responses to the threat of climate change: mitigation and adaptation.

When we mitigate, we work to produce less greenhouse gas pollution. This limits how much warming can take place.

When we invest in adaptation, we invest in ways to protect ourselves from warming, like building sea walls to protect against rising sea levels.

These two types of action have different effects on the risk humanity is facing. Specifically, mitigating reduces how bad the worst-case scenario will be. Adaptation improves how good the best-case scenario could be.

In the following graphics, the quantity being measured along the horizontal axis is human suffering. We cannot be sure exactly what the correct value is, but we have good reason to believe that it is within the range defined by the yellow bar.

With no action:

With mitigation:

With adaptation:

Given how bad climate change could be, I think the strong emphasis must be on mitigation. It is as though you are a patient, about to have an operation. The surgeon tells you that with the normal operation, there is a 10% chance that you will lose a leg and a 5% chance you could die. She then tells you that they can modify the operation in one of two ways:

a) Cut the chance of losing a leg to 5%
b) Cut the chance of dying to 2.5%

It seems far more sensible to choose option b.

With climate change, we don’t need to choose ‘100% mitigation’ or ‘100% adaptation’. Nonetheless, I think the same logic that lies behind the surgical decision lies behind the moral imperative for humanity to concentrate on mitigation.

Why care about 2100?

I know it sounds obscure and Klingon to say it, but protecting future generations from climate change is a matter of honour.

As far as scientists can tell, climate change is the most serious major threat facing people a couple of hundred years from now – worse than nuclear proliferation, worse than other environmental problems. If the icesheets really start melting, they will have major problems. How many times in history have dozens of major cities been moved?

At the same time, we have the technology now to stop climate change by abandoning fossil fuels over the span of a few decades. It will be expensive to do that, but it will bring other advantages. Fewer people will die from air pollution. We won’t need to import fuel from dangerous places or produce it in incredibly destructive ways like the oil sands.

It will probably use up a lot of land, but it seems possible that it can be made to work in a way that is fair for all of humanity, with everybody living in comfort.

We are lucky that we live in this generation – the one that will start to pay the cost of decarbonization. That is far preferable to being part of the generation when the actual warming of the planet peaks after all the lags kick in.