[gtsop]

When I was a kid my teacher told me trees convert co2 to oxygen. If I had to suck co2 out of the atmosphere I would plant more trees and stop choping/burning down existing ones. It is cheap, sustainable and aesthetically pleasing, but I guess this isn't tecky enough for today's world. Maybe if we add a wifi module on trees it would fix it.

[MauranKilom]

Trees do that, but what happens when they die? Planting trees to fix CO2 emissions is like fixing the leak in your roof by putting more buckets below. Sure, it helps a bit, but it only buffers the water - you still need to dump it. Similarly, we need to get carbon out of the cycle.

For reference, some googled numbers:

- The amazon rainforest holds about 123 billion tons of carbon in total.

- For the past decade, we've emitted about 35 billion tons of CO2 (around 10 billion tons of carbon) annually.

You'd need to plant a whole new amazon forest every 10-20 years to balance out our emissions. And that's assuming our emissions don't keep growing exponentially like they've done in the past - otherwise you'll run out of land to plant forests on in a couple of decades.

[euroderf]

Now that we have consumed so many oil & gas deposits, do we simply have too much carbon ? Could a space elevator start taking loads of carbon (in whatever state of matter) and dispersing them into space ? It would be a testbed for Venus, which most definitely has way too much carbon. Dispose of a few zillion tons and then terraforming becomes more realistic.

[renewiltord]

If we just build houses out of the trees we can keep the carbon out for a long time.

[MauranKilom]

That is an approach. Note though that, again, the total number of houses at any given moment is not going to exceed a certain number, and when we replace houses, we more or less set free the carbon in the previous one. So once again, this is more like a bucket than a drain.

[downWidOutaFite]

From a kid's level of understanding you could also deduce that the carbon must end up in the plant matter, and that a forest's plant matter density doesn't increase forever. Old forests reach a carbon-neutral equilibrium (decaying plants release carbon). New forests suck up carbon until they reach that equilibrium.

Another idea you could deduce from this is that if we remove plant matter from the forest, and lock that carbon up so it doesn't go back into the atmosphere, it could become a long term carbon-sink. Even better if the plant matter can be useful. So vast lumber farms with the fastest growing trees you can get could be a good carbon capture technology.

[gtsop]

I think more information is needed as input here. In pwrticular, what is the ratio of consumed/stored co2 in the photosynthesis process. My super basic understanding is that co2 is being used as fuel to convert energy into tree-food. By that logic i would expect at least a portion of the co2 to be actually transformed to other elements rather than stored as-is into the tree.

[downWidOutaFite]

Your intuition is correct. The basic photosynthesis chemical formula is

  6CO2 + 6H2O + (light) ---> C6H12O6 + 6O2

The carbon goes from CO2 to C6H12O6, which are carbohydrates. The carbs are used by the plants for both energy and plant matter. The carbs that are used for energy are released back into the atmosphere as CO2 via cellular respiration. For carbon sequestration what matters is that the carbon in the plant matter stays fixed and doesn't get converted back into CO2 and released.

[mynegation]

It will help a bit but not all the way. When trees die, CO2 is released again by fungi and bacteria in the process of making the wood rot.

[kgin]

Trees are essential, but we've released into the atmosphere so much carbon that was previously trapped under the earth in liquid and solid form. Trees aren't enough, we need to get that carbon back into long term storage.

[tunesmith]

From what I understand, planting trees isn't sufficient, but it would sure help.