4 ms·

You are not removing it, it is just converted to heat (in several steps).

by kaybe 7y ago

consumer451 7y ago
Ok yeah, I guess the only way to remove it for now would be something like solar or wind powered carbon sequestration?
- kaybe 7y ago
  The current problem we have is the energy imbalance between incoming solar radiation and outgoing thermal radiation, since a growing proportion of the latter is blocked. Any quantity influencing this balance could theoretically be used to get back to the old point. The discussed options are either solar radiation management which lowers the amount of incoming radiation or carbon capture which would allow more outgoing thermal radiation to escape. The first option has ideas such as stratospheric sulfur injections (increasing albedo leading to more reflected incoming sunlight), deploying a sunscreen in space or simply painting areas white. (It should be noted that humanity has been causing albedo changes for a long time simply by changing land cover. Forests have lower albedo than fields, for example.) The problem with the ideas is that they are very unstable. Many need constant renewal and management to be kept active. There are also side effects apparent in the model such as changed atmospheric circulation patterns for some of them, and the ocean acidification due to dissolved CO2 etc are not addressed either. The second option, carbon capture, can be achieved by different means. Basically, carbon needs to be stored in one of the sinks available. The natural sinks are the biosphere (quite small, but increasing it will help) and chemical weathering. If we wait long enough, chemical weathering will lower the CO2 concentrations sufficiently. [0] So one of the ideas here is to increase the speed of the weathering by increasing the surface and availability of the the stone to weather. Others are increasing the biomass sink by planting more of it or fertilizing the oceans so the algae can grow faster and take a part to the ocean floors. Then there is technical carbon sequestration, which needs energy input (you're talking about this, right?). Where the energy comes from shouldn't matter as long as the carbon emission is smaller than the sequestration. I guess all renewable energies and nuclear should work fine. (Maybe there will be a better technology at some point in the future as well, but better not rely on it.) However, now this carbon needs to be stored, which is a problem in itself. Ideas are simply pumping it into the ground, for example depleted natural gas fields (unstable!) or changing it to other forms which needs more energy. (Any energy that can be changed to chemical energy is actually removed from the system, but that will probably not be very much. I'd have to check up on this though, I've found my intuition is not that good yet for these numbers.) There is not a lot of money in it yet, which makes research slow. This is still most probably our best shot. All but one scenarios of the IPCC-1.5°C report have carbon sequestration from 2030 - in 10 years - (in the worst case on the order of half of current emissions!), and the one that doesn't uses biomass capture. We cannot reach a path of <= 1.5°C warming without it. [1] [0] https://skepticalscience.com/weathering.html https://skepticalscience.com/weathering.html [1] https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3b-724x1024.png https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3...

You are not removing it, it is just converted to heat (in several steps).

by kaybe 7y ago

You are not removing it, it is just converted to heat (in several steps).

consumer451 7y ago

Ok yeah, I guess the only way to remove it for now would be something like solar or wind powered carbon sequestration?

kaybe 7y ago
The current problem we have is the energy imbalance between incoming solar radiation and outgoing thermal radiation, since a growing proportion of the latter is blocked. Any quantity influencing this balance could theoretically be used to get back to the old point. The discussed options are either solar radiation management which lowers the amount of incoming radiation or carbon capture which would allow more outgoing thermal radiation to escape. The first option has ideas such as stratospheric sulfur injections (increasing albedo leading to more reflected incoming sunlight), deploying a sunscreen in space or simply painting areas white. (It should be noted that humanity has been causing albedo changes for a long time simply by changing land cover. Forests have lower albedo than fields, for example.) The problem with the ideas is that they are very unstable. Many need constant renewal and management to be kept active. There are also side effects apparent in the model such as changed atmospheric circulation patterns for some of them, and the ocean acidification due to dissolved CO2 etc are not addressed either. The second option, carbon capture, can be achieved by different means. Basically, carbon needs to be stored in one of the sinks available. The natural sinks are the biosphere (quite small, but increasing it will help) and chemical weathering. If we wait long enough, chemical weathering will lower the CO2 concentrations sufficiently. [0] So one of the ideas here is to increase the speed of the weathering by increasing the surface and availability of the the stone to weather. Others are increasing the biomass sink by planting more of it or fertilizing the oceans so the algae can grow faster and take a part to the ocean floors. Then there is technical carbon sequestration, which needs energy input (you're talking about this, right?). Where the energy comes from shouldn't matter as long as the carbon emission is smaller than the sequestration. I guess all renewable energies and nuclear should work fine. (Maybe there will be a better technology at some point in the future as well, but better not rely on it.) However, now this carbon needs to be stored, which is a problem in itself. Ideas are simply pumping it into the ground, for example depleted natural gas fields (unstable!) or changing it to other forms which needs more energy. (Any energy that can be changed to chemical energy is actually removed from the system, but that will probably not be very much. I'd have to check up on this though, I've found my intuition is not that good yet for these numbers.) There is not a lot of money in it yet, which makes research slow. This is still most probably our best shot. All but one scenarios of the IPCC-1.5°C report have carbon sequestration from 2030 - in 10 years - (in the worst case on the order of half of current emissions!), and the one that doesn't uses biomass capture. We cannot reach a path of <= 1.5°C warming without it. [1] [0] https://skepticalscience.com/weathering.html https://skepticalscience.com/weathering.html [1] https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3b-724x1024.png https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SPM3...