The study, published Wednesday in the journal Nature, found that global carbon storage capacity was 10 times less than previous estimates after ruling out geological formations where the gas could leak, trigger earthquakes or contaminate groundwater, or had other limitations. That means carbon capture and storage would only have the potential to reduce human-caused warming by 0.7 degrees Celsius (1.26 Fahrenheit)—far less than previous estimates of around 5-6 degrees Celsius (9-10.8 degrees Fahrenheit), researchers said.
“Carbon storage is often portrayed as a way out of the climate crisis. Our findings make clear that it is a limited tool” and reaffirms “the extreme importance of reducing emissions as fast and as soon as possible,” said lead author Matthew Gidden, a research professor at the University Maryland’s Center for Global Sustainability. The study was led by the International Institute for Applied Systems Analysis, where Gidden also is a senior researcher in the energy, climate and environment program.
Two factors, basically.
Vegetation rots back out to the atmosphere. Bogs are better in that way, because they trap and grow over their own detritus. Managed forests are also pretty carbon-negative, because the carbon is now trapped in whatever wood products for centuries. Ocean-based stuff has had mixed results, though. You could also char and dispose of your biomass before it rots, but now you’re adding complexity.
Which brings us to the second: It might be expensive and slow, relative to just artificially capturing it and shoving it underground. Plants are not known for their speed, and reasonably moist land is expensive.
That being said, it’s still a serious contender for how to take care of carbon we’ve already burned, alongside this and other options like grinding up and spreading certain kinds of stone.