Leaving aside any debate of whether CO2 is the cause of global warming..........it appears there's now a number of prizes ( one by Virgin recently ) for anyone who can invent the best method of removing CO2 from the atmosphere.
Of course, the problem is.........you have to remove 6 billion tons ( conveniently...one ton for each person on earth ) a year, in other words outdo all the output of every factory and home on Earth.
And the mega factory where you do this is going to want power !
Originally posted by Chi Squared: Leaving aside any debate of whether CO2 is the cause of global warming..........it appears there's now a number of prizes ( one by Virgin recently ) for anyone who can invent the best method of removing CO2 from the atmosphere.
Of course, the problem is.........you have to remove 6 billion tons ( conveniently...one ton for each person on earth ) a year, in other words outdo all the output of every factory and home on Earth.
And the mega factory where you do this is going to want power !
Any ideas ( crazy or otherwise ) welcome.
Well sometime ago many 1000's of meters of limestone was depostied all across the world in the deepest oceans.
Genetically engineered plankton that are better at creating calcite skeltons might be able to do this, I suppose.
You've got the problem that for every ton of carbon you get over 8 tons of calcite.
I've wondered before whether it would be economical to run an air refrigeration plant feeding a powerstation. Separate the oxygen, nitrogen and CO2 from the air and you can then burn coal in pure oxygen (no nasty NOX's) release the unwanted nitrogen and sequester the CO2.
Of course where you put the liquid CO2 is a very hard problem. It's very corrosive, needs to be kept at low temp or high pressure, and it's not like nuclear waste that might actually stop being dangerous eventually. (maybe you can do some controlled venting once you have fusion sorted out)
If you can use the waste heat then refrigerationcan theoretically be more than 100% efficient, so that might help.
Genetically engineered plankton that are better at creating calcite skeltons might be able to do this, I suppose.
You've got the problem that for every ton of carbon you get over 8 tons of calcite.
I've wondered before whether it would be economical to run an air refrigeration plant feeding a powerstation. Separate the oxygen, nitrogen and CO2 from the air and you can then burn coal in pure oxygen (no nasty NOX's) release the unwanted nitrogen and sequester the CO2.
Of course where you put the liquid CO2 is a very hard problem. It's very corrosive, needs to be kept at low temp or high pressure, and it's not like nuclear waste that might actually stop being dangerous eventually. (maybe you can do some controlled venting once you have fusion sorted out)
If you can use the waste heat then refrigerationcan theoretically be more than 100% efficient, so that might help.
Liquified CO2 could be injected into the earths crust at subduction zones like the Marians trench.
You wouldn't see it again for millions and millions of years
The process of forming limestone and it subducting in this way is actually part of the carbon cycle anyway.
It focused on ideas presented to a NASA conference, looking at possible ways of using technology to *reduce* global temperatures.
Three ideas involve reducing effective solar irradiance:
1. Creating a solar shield in space, composed of thousands of tiny glass reflectors, which would deflect a tiny proportion of sunlight away from the earth, but sufficient to have a significant cooling effect (this was by far the most technically challenging and costly strategy proposed) 2. Fire hundreds of rockets loaded with sulphur into the stratosphere, to create a cooling blanket of aerosol particles, reflecting light back into space 3. A fleet of some 200 remote controlled, high-tech, ocean-going wind-powered yachts, constantly firing a fine mist of sea water up into the clouds -- increasing the thickness of the clouds and hence, the cloud albedo effect. (This seems to be the least expensive of all five options).
The other two concern reducing CO2 levels:
4. Bring life to some of the vast "dead zones" in the world's major oceans by feeding them with nitrate nutrients. This would feed vast blooms of plankton -- which would naturally consume CO2, releasing oxygen... and on their death, the carbon in the plankton cells just filters harmlessly down to the sea bed. 5. Build forests of artificial trees -- designed to extract CO2 from the air, by a process similar to the way real trees do this, only hundreds of times more efficiently. The carbon extracted in this way forms a powder, which could be buried beneath the earth (e.g., in deep caves and boreholes, emptied subterranean oil caverns etc.)
This is all blue-sky thinking, of course. (Hmm, inappropriate metaphor, perhaps!). Anyway, all these ideas are in the early stages of development -- and some could be associated with major hazards; the sulphur rockets one seems potentially very risky. But perhaps the time will come when we'll really need ideas like these.
* Free-thinking does not just mean choosing to believe whatever makes you feel good. There's no thought at all in that. *
5. Build forests of artificial trees -- designed to extract CO2 from the air, by a process similar to the way real trees do this, only hundreds of times more efficiently. The carbon extracted in this way forms a powder, which could be buried beneath the earth (e.g., in deep caves and boreholes, emptied subterranean oil caverns etc.)
This is probably the most doable and effective way.
If only we could get over the "frankenfood" fears...
The idea of increasing CO2 drawdown by seeding nutrient-impoverished oceans (particularly the Southern Ocean) has been around for at least 15 years (I first heard of it as an undergrad in the early 90s). It would be technically the easiest and with fewest other environmental problems to overcome.
As for dropping nuclear waste doen subduction zones, this again has been seriously suggested and is technically quite sensible (provided you can develop adequate containment to get it to the required depth). The advantage is that once down there, it will be dispersed to such an extent as to be insignificant when it gets recycled to the lithosphere (and still tied up in granite or similar). Of course, it falls foul of the green agenda for not touching the oceans at all, regardsless of whether it is a practical and pragmatic solution to the problem. Certainly a better idea that deep crust burial, although this can be successful if a sensible location is found for the underground repository (i.e. not picked just because it is next to Sellafield)
Originally posted by Dr Ian B: Of course, it falls foul of the green agenda
I think it also falls foul of some in the nuclear lobby who think that we might actually need that waste at some future date. After all, there might be a lot of uranium in there that we will eventually want to feed into a fast breeder.
OK, Wiki has it. Apparently it's ~5000ppm. Has anyone modelled what the temperature would be like at that level of CO2, or would we be long gone before it ever got that high?
