That helps me see whats up. Thanks Sam and Chronos.
Roughly, hydrocarbons (gasoline) weigh a bit more than the carbon in them, the hydrogen not so much. Carbon has molecular weight around 12: oxygen around 16, CO2 around 44, which is 3.7 times as much as carbon: 6 pounds of carbon gives around 22.
Allowing for the hydrogen, 6 pounds of gasoline gives 20 pounds of CO2, so that sounds about right.
(Edit: damn, what are you all doing here at this time of day. Hang on, what am I doing here at this time of day?)
This article (Hanson, 2013) discusses this. It would apparently cost from $50 trillion to $200 trillion to capture and reduce atmospheric CO2 by 50 ppm: Assessing “Dangerous Climate Change”: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature
The referenced 2012 article by the American Physical Society was “Direct Air Capture of CO2 with Chemicals: A Technology Assessment for the APS Panel on Public Affairs”
NETL estimates we have domestic geological capacity for 3 to 22 trillion metric tons – far more than we’ve released since the start of the industrial revolution. And that’s just in the US.
I’m LOLing at the idea of converting any of this to oxygen and carbon black. Then we’ll have a “where do we put it” problem. We were joking at work about stuffing it back into old mined coal seams.
That sounds a like a great idea.
Chemical plants have been capturing CO2 and sequestering it for decades now. Every time you make Urea, CO2 + 2NH3 —> CO(NH2)2 + H2O, you are capturing CO2.
The Dakota gasification plant converted low rank coal to synthetic natural gas and pumped CO2 to Canadian oil fields for enhanced oil recovery.
A big economic and engineering factor, missing in the discussion is the purification of CO2 removed either from flue gas or from the atmosphere. For example, CO2 needs to be bone dry to flow through pipes otherwise it will eat the pipes up. Cleaning up CO2 needs energy which seems to be missing from a lot of papers cited above.
Here is a video about that project that was released a few days ago.
We don’t, really. The entire cost of the Iraq/Afghanistan war so far, for example, is estimated at around 6 trillion dollars, and that’s over fifteen years. The combined annual GDP for the entire world is something like 80 trillion dollars.
Which three-eighths of the total yearly economic activity of the whole world do you suggest we could do without to get the $30T for this endeavor? Even a six-billion-dollar Mars mission is just couch-cushions change compared to this kind of money. (And don’t forget that unless we massively reduce our greenhouse-gas emissions, we’d have to keep doing this expensive atmospheric CO2 removal indefinitely if we want to control climate change.)
Total mass of carbon dioxide in the atmosphere is roughly 3,200 billion metric tonnes. Total world paper production is about 400 million metric tonnes.
If we bury all the world’s paper production for the next 4,000 years we’d halve the carbon dioxide in the atmosphere! (Assuming of course that the paper production and burial is a carbon zero process…)
That’s almost exactly the same amount of plastic that’s created each year. And plastic sequesters carbon, but again the amount is trivial compared to how much CO2 we emit.
I realize that was somewhat tongue in cheek. But the carbon dioxide in the atmosphere is in equilibrium with carbon elsewhere, it would take longer than that.
Doesn’t the carbon in plastic mostly come from petroleum rather than atmospheric CO2?
If we get rid of the CO2, wouldn’t that be really bad for the world’s plants?
While I hope this is meant facetiously (since no one is talking about reducing carbon below historical levels to amounts below what plants can use), the dynamics of CO2 take-up up by plants under increased atmospheric levels is an area of active research. Plants both take up CO2 through photosynthesis, and also produce it through respiration. While increased CO2 may increase photosynthesis and plant growth, higher temperatures may both inhibit photosynthesis and increase respiration, so that some forests could end up as net producers of C02 rather than carbon sinks as they are now.
We certainly do not want to get rid of all CO2 in the atmosphere. Or even most of it.
While CO2 in the atmosphere has fluctuated over time it has hung out around 280ppm. Currently it is around 415ppm. About a 33% increase.
So, assuming it works like this (not sure it does), we’d want to take that 3,200 billion metric tonnes figure and reduce it by 1/3 to around 2,100 billion metric tonnes (so we need to remove 1,100 billion metric tonnes plus any extra we keep producing).
I wonder if removing plants were very localised, would CO2 levels even out eventually or would there be “islands” around plants with low CO2 levels and not much difference in other places.
Pure carbon dust aka soot? The amount that would blow away would do a good job of blocking out the sun, cooling the planet eventually.
Maybe put up a few windmills to blow the air around? 