The Tricky Future of Capturing the World’s Carbon Emissions

Some types of pollution don’t hang around in the atmosphere very long; they break down through chemical reactions or wash out with the rain in a matter of weeks or years. Carbon dioxide, on the other hand, takes a very, very long time to naturally scrub away.

Even if we stop emitting more of it today, the concentration of carbon dioxide will stay high for centuries.

In a previous story, we looked at ways to intentionally cool the climate by doing things like injecting sunlight-reflecting particles into the upper atmosphere. That could potentially ease the effects of climate change.

But the root cause has to be addressed either way — we have to stop the rise of greenhouse gas concentrations in the atmosphere. Wouldn’t it be great if we had an “undo” button for the greenhouse gas that we have already pumped up there?

If you’re thinking the solution is as easy as planting trees, I have some bad news for you: While it’s true that photosynthesizing plants take in carbon dioxide and “exhale” oxygen, they really only take up enough carbon to build their own cells. And when a plant dies and decays, most of that carbon ends up right back in the atmosphere.

Forests aren’t so much “lungs” that constantly filter out carbon dioxide as they are standing…