Climeworks has just opened the world’s largest direct carbon capture plant. It can suck around 36,000 tons of CO2 from the air each year, burying it underground.
Has anyone done the math and figured out if these things are more efficient than trees? I have my doubts but I'm also a pleb so idk how to compare them.
I haven’t done the math but I studied a lot energy stuff for my degree. I can say for sure that’s it’s a hell of a lot more money and work than just reducing emissions in the first place. The below comment is accurate, if cynical; I knew someone who works on it in the states. You collect a bunch of co2 (using energy), then compress it (with energy), then ship it (yep diesel trucks), to salt caves where it is pumped (with energy) into the empty salt lined cave where the pressure causes the salt to sort of seal in a partial melt from the pressure. And hope we don’t accidentally frack it all back out. Needless to say I think it’s a waste of technology, money, and political will that’d be better spent on a plethora of other options.
Here in Iceland, where this is located, we produce more green energy than we consume and can't store that energy, and the carbon is pumped straight into the basalt below which absorbs it. I think doing it here is a decent way to do research on improving the technology.
I mean just looking at the amount of concrete in that picture, I get pessimistic. When will this particular site have dug itself out of the carbon "hole" created by its construction?
As for trees: That is really, really hard to measure and even harder to know in advance. Some factors appear to be:
different tree species store different amounts of carbon
tree plantation or actual forest?
prior use of the site (e.g. meadows do store carbon too)
development over time (most trees need to grow a couple years before they start storing significant amounts of carbon)
failure of sites due to being planted in a bad way (e.g. a lot of Chinese Green Wall sites and quick-buck billion tree projects seem to be affected by this)
IIRC, a tree absorbs up to 3 tons/year, and takes a bunch of years to get to that stage.
The trees also don't sequester underground, and will need surface area staying as forest for the rest of time.
As many have echoed: an ounce of prevention saves a pound of cure. Most bang for our buck would be to change our lifestyle and regulations. But as that's not feasible we're at the geo engineering and artificial sequestration stage.
CO2 generally is released in cycles. Wood rots, new forests grow etc. The biggest issue is that we went from slow cycles such as carbon is stored in fossil fuels that VERY slowly release CO2 through natural processes, to extremely rapid release of CO2.
How do you measure "efficiency" ? By money spent? Then yes, trees are currently cheaper. But trees are complicated (see other comments). Additionally, even if we cover the whole landmass with trees, there is still a catastrophic amount of Co2 left in the atmosphere.