Module 9: Geoengineering

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Overview

We have logged, plowed or paved much of the land, dammed rivers, and otherwise engineered the Earth to serve us. So, could we “geoengineer” our way out of the problems from fossil-fuel CO2 changing the climate? Maybe…

We could take CO2 out of the air and put it back in the ground, either by capturing the CO2 and squeezing it to liquid, or by greatly speeding up the natural processes that will remove our CO2 over the next few hundred thousand years. But, liquefying our CO2 would generate more than the initial amount of fossil fuel because burning adds oxygen, requiring a huge and expensive operation. And, we don’t yet know how to speed up the natural processes cheaply enough to do the job.

Instead, we could just block the sun, putting reflective materials in the air or in space. But, the ocean would continue to acidify, while droughts would become more common. And, deciding whose hand would be on the thermostat, and how to keep the sun-blocking activities going for thousands of years or longer while our CO2 remains in the air, pose very difficult questions.

Some people think it is crazy to even talk about geoengineering, and especially the sun-blocking part. But, if we were faced with a world so hot that unprotected people would die in the tropics, blocking the sun might start to look like a way to make the best of a really bad situation. So, let’s have a look at this confusing and contentious topic.