Removing CO2 From the Air Efficiently 487
Canadian scientists have created a device that efficiently removes CO2 from the atmosphere. "The proposed air capture system differs from existing carbon capture and storage technology ... while CCS involves installing equipment at, say, a coal-fired power plant to capture CO2 produced during the coal-burning process, ... air capture machines will be able to literally remove the CO2 present in ambient air everywhere. [The team used] ... a custom-built tower to capture CO2 directly from the air while requiring less than 100 kilowatt-hours of electricity per tonne of carbon dioxide."
Natural device? (Score:5, Insightful)
Don't we have a device that removes CO2 from the air? I thought they were called "trees."
Re:Natural device? (Score:5, Funny)
I suppose you eat dolphin safe tuna as well?!
Re:Natural device? (Score:5, Funny)
How exactly do trees generate jobs?
Well...people could be paid to plant them. Yeah, I know that trees can do this on their own....but can they do it in nice neat rows?
Re:Natural device? (Score:5, Funny)
That's a great idea ... we could even employ people to selectively cut the trees down, and others to mill the timber, and others to make things with it. I think it's possible to come up with a viable business model where we sell people products made from converted atmospheric carbon.
I'm off to the patent office!
Re:Natural device? (Score:5, Funny)
Re:Natural device? (Score:4, Insightful)
Paperwork is SO 1929. Everyone does things electronically now. You can bankrupt the nation entirely over the Internet now!
Re:Natural device? (Score:5, Funny)
I suppose you eat dolphin safe tuna as well?!
No, but I do eat tuna safe dolphines. hmmm
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Human's are fascinated with Rube Goldberg-type machines. It would be even better if there were balls rolling around an endless track as part of the process...
You mean it might contain bearings?
Re:Natural device? (Score:5, Interesting)
Yes, but nature already has a robust way of dealing with it's own carbon sink. Having tons of liquified CO2 sitting around does not sound like a long term solution. While it's a clever technological fix, it does not solve the fundamental problem Kind of like puting ice on a febrile patient instead of giving them antibiotics to kill the infection.
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Re:Natural device? (Score:4, Insightful)
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(runs to patent office)
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If we're serious about reducing the carbon dioxide level by growing trees, we'll have to cut them down and store the wood somewhere where it won't decay. We will also have to replenish the trace elements taken from the soil by those trees so we can grow more. This could work to slowly remove the excess carbon dioxide we've released, but I don't think it would be feasible to keep up with our current rate of emissions.
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They don't respirate as much CO2 as they take up. The carbon from the difference is used to build more tree.
Re:Natural device? (Score:4, Insightful)
They won't be making a pile of cash out of trees.
Can't resist:
1) Identify a possible source of trouble
2) Invent a fix, no matter how convoluted it is
3) Patent it and market it
4) Profit
Just wonder how much do we have to wait for a fart capture device (cow farts are actually a major source of trouble)
Re:Natural device? (Score:5, Funny)
Man! Cut it out!
It's THREE steps, not four, and you CAN'T specify the intermediate one! Jeezuz...
Re:Natural device? (Score:5, Funny)
Just wonder how much do we have to wait for a fart capture device
Thank you, Argentina. [bbc.co.uk]
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Just wonder how much do we have to wait for a fart capture device (cow farts are actually a major source of trouble)
This has already been done in Holland - no waiting required, therefor - a university study group has work in progress on the subject of cow farts. There are groups of cows standing around with cylinders strapped to their backs in order to (forgive the word) fuel this study. Saw it on /.
Cow Farts... wrong end! (Score:5, Informative)
They won't be making a pile of cash out of trees.
Can't resist:
1) Identify a possible source of trouble 2) Invent a fix, no matter how convoluted it is 3) Patent it and market it 4) Profit
Just wonder how much do we have to wait for a fart capture device (cow farts are actually a major source of trouble)
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So we need to kill all the vegetarians, right?
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How do we kill countless billions?
I mean, we kill lots of delicious cows, sure -- but you'd think the people whose business it was to sell us the delicious cow meat would be counting them.
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I agree that they're orthogonal opinions. I just happen to disagree about the "moral degeneracy" bit. While the environmental damage is nonzero, it's sort of a curveball, as your original comment was only about killing animals.
While it may not apply to you, I find it interesting that many "moral vegetarians" are in the naturalistic-fallacy camp, but animal husbandry and the human consumption of meat are hardly unnatural.
Please make any responses more clear. The phrase "massive environmental damage moral deg
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Actually methane from bovines is expelled in the form of burps, very little methane is farted out.
Re:Natural device? (Score:5, Funny)
Don't we have a device that removes CO2 from the air? I thought they were called "trees."
I hooked a tree up to 100kW, and it added CO2 to the air instead.
Physically impossible! (Score:5, Insightful)
According to David MacKay [withouthotair.com]:
In other words: It'll be at least 200kW per tonne, unless they think the CO2 will somehow magically compress itself to be stored, which is not going to happen. That, or they just invented a perpetuum mobile.
Re:Natural device? (Score:5, Interesting)
The scrubber sounds pretty effective. No waiting for it to grow, and it's more space-efficient, which is good for cities and industrialized areas.
Re:Natural device? (Score:4, Interesting)
This may be Bad Math, but... The article says, "The tower unit was able to capture the equivalent of approximately 20 tonnes per year of CO2 on a single square metre of scrubbing material -- which amounts to the average level of emissions produced by one person each year in North America." A page I dug up [carbonify.com] claims a single tree removes "on average 50 pounds (22 kg) of carbon dioxide annually over 40 years."
The scrubber sounds pretty effective. No waiting for it to grow, and it's more space-efficient, which is good for cities and industrialized areas.
Yep, and we only ned 450,000,000 of them to keep up with the carbon output of the denizens of North America.
It's not clear from the wording whether that includes the output of North American industry, or just the habits of individuals.
Re:Natural device? (Score:5, Insightful)
Cant we just grow up now and realise we have to
be moderate in our consumption of the planets resources instead of trying to trick our way out ?
I don't think you understand human nature. Your solution requires changing a significant percentage of the population's behavior - I don't give it much chance of success.
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The earth can deal with a certain amount of carbon itself though, so you might not need all 450 million.
It would at least be beneficial in slowing down global warming until we have a better solution.
But you know damned well that 99% of the population is going to say: "Ok, great! We've got these CO2 filter thingies now, so the problem is solved. Now where's the keys to my Hummer?"
And the better solution is never going to come along.
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And trees which are being GM'ed to grow faster and/or remove more CO2 are under attack by eco-terrorists.
I'm not going to search, but I'd thought that grasslands were more efficient CO2 sinks than trees
Re:Natural device? (Score:4, Insightful)
I think oceans also do a pretty good job at that. And at the end of the chain you even get more fish (which is, to a certain extent, fixed carbon).
Re:Natural device? (Score:5, Interesting)
They are, the only downside is that the oceans are gradually becoming acidic (carbonic acid) from all that CO2 being produced.
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Poplar trees are about 10 tons per acre. Which is about 2.5kg of wood per square meter.
From: http://www.physorg.com/news75568548.html
And oil palms produce about 0.6 kg of oil per square metre.
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Yea but planting a few billion tree's and letting them grow themselves is a heck of a lot easier than building hundreds of millions of these towers.
Re:Natural device? (Score:5, Funny)
If apostrophes meant "ZOMGHereComesAnS", we would type "treeZOMGHereComesAnSs", but they don't, so we don't.
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Re:Natural device? (Score:4, Insightful)
But that isn't the point. You can use the wood for making stuff and so it hangs around as paper or a table for years. It all eventually goes back of course but if we were to use more paper and less plastic, you'd be storing a lot of it temporarily and the amount stored in "the system" would be higher.
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How often are you going to have to remove this material? Probably fairly frequently considering that it is going to be accumulating something like 55kg per day.
The scrubber sounds pretty effective. No waiting for it to grow, and it's more space-efficient, which is good for cities and industrialized areas.
Trees are fai
Re:Natural device? (Score:5, Funny)
Hockey sticks?
Re:Natural device? (Score:4, Informative)
But you are correct in the fact that this would require maintenance, since there's no such thing as maintenance free pumps.
However i still feel if this could be a good solution, if it's cost and energy efficient, and being financed by carbon-taxing, and last but not least, F/OSH (free/opensource hardware).
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It is impossible for a device like this to be cost efficient in the present. It is unknown if it is cost efficient in the long run. Here's what I mean (caveat: I'm focusing wholly on economics here, not politics):
These devices require a fixed cost to produce (in terms of materials not available for other machines, labor not available for other activities, cost of required associated infrastructure, etc.) and a recurring cost to operate (energy not available for other things, maintenance labor and parts no
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Don't we have a device that removes CO2 from the air? I thought they were called "trees."
Yes, but when the trees eventually die they are decomposed and release the CO2 into the air again (or in the case of biofuel, they release it into the air again when burned). It is a carbon-neutral system, both when left alone and when used as a fuel.
I imagine an approach like this would be considerably less efficient than, say, putting CCS devices on coal plants. If it "costs" 100 kWh / tonne of CO2 at a normal location, you'd most likely get better efficiency if this was done where the air concentratio
Re: (Score:3, Interesting)
You can always capture their carbon and tuck it away in a sealed mine.
At the office, I joke that by printing a lot you are actually helping reduce CO2 because paper comes from fast-growing trees that eat up a lot of carbon in the process. As far as you don't burn it, you are reducing your carbon footprint. If we gathered all the paper we have to print and buried it deep we would be both reducing carbon in our biosphere and offering a nice stockpile of fossil fuel for the cockroach civilization that will fol
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Any green plant will do. How difficult would it be to pipe the exhaust from a coal fired powerstation through some greenhouses. Which is the obvious place to put a "greenhouse gas" in the first place
Re:Natural device? (Score:4, Interesting)
And now the catch ... while this tower is beyond inefficient :
Coal produces 2.117 pounds per kwh.
= 0.000960255047 tonne per kwh.
= 1041 kwh per tonne Co2
This needs about 10% of that power, combined with some 15% transmission loss, and the fact that this is a lower bound over time (obviously if we lower athmospheric co2 this cost will raise).
That means we need 23% or about 1/4th of total energy to merely break even. Petroleum and gas aren't that much better, and aren't feasible over even the medium term anymore. To actually make a difference we'd need 50% of all energy produced, which means our generating capacity needs to rise by 100% (and not 50% because if we raise it by 50% we'd have 1.5 times the energy which would be divided into 0.75 for carbon nonsense and 0.75 for us. So we'd need 200% of the energy making it 1 unit for us, and 1 unit for co2 nonsense).
That's not exactly good news, is it ? It gets worse.
Trees are much worse in efficiency than this. Yes, they do produce their own energy. They're however 2% efficient solar panels (so in reality a tree presents lost energy, in that a solar panel could have been standing where the tree stood and produce about 20 TIMES more energy, making these towers more efficient even if trees were 100% efficient chemical machines, since that would only give them 5% of the efficiency of the solar panels).
Well trees do about 650 kg per tree per year. Needless to say this is beyond pitiful. Using solar panels to power a tower like this would replace a forest in about 100 square meters. Combine this with the need to double generating capacity in order to make the towers work and you'll see exactly where this would be going in the real world.
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One of the major problems with algae-based biofuel is a lack of easy to obtain concentrated carbon dioxide.
So desert + CO2 machine + solar panels + algae = self-powered biofuel engine
Re:Natural device? (Score:4, Interesting)
Don't we have a device that removes CO2 from the air? I thought they were called "trees."
Well, yes... but the rate at which trees remove CO2 from the air is not very high. Moreover, left to nature, much of that CO2 is usually released again at the end of the tree's life, when it usually rots slowly. If, however, the tree is harvested for human use, most of the CO2 may be released rapidly (firewood), or some of it may be stored for decades to centuries (construction, paper).
Either way, the net rate of fixation of CO2 is rather limited, and far less than the rate of release of fossil carbon. Nature required many millions of years for plants to convert CO2 into reserves of fossil hydrocarbons.
CO2 has also been removed from the atmosphere via the oceans. Many shelly organisms use dissolved CO2 to build their shells. On death, some of these sink, eventually forming carbonate sediments. Geologic processes have been releasing CO2 from carbonate sediments at a similar (but probably lower) rate.
http://en.wikipedia.org/wiki/Carbon_cycle [wikipedia.org]
In modern times, industry has been releasing fossil carbon as atmospheric CO2 at a rate some orders of magnitude faster than the net rate of removal of CO2 by plants and shelly creatures. There's the rub. To reverse the buildup of atmospheric CO2, we need something beyond mere forests and diatoms.
Re:Natural device? (Score:4, Insightful)
I call bullshit on this one. As long as plants need carbon to build their bodies, they will be CO2 absorbers, at least until they die and decompose.
Is it effective? (Score:3, Insightful)
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I assume that this device would be used with clean renewable energy sources to remove CO2 we've already pumped into the atmosphere. So, you'd run this thing at night when energy prices are low (around 1-2 cents/kwH) to help bring the atmosphere back into balance (and of course, you must be using wind or some other non-fossil fuel for electicty, duh).
A couple of these machines by themselves won't do much, but hundreds of thousands of them powered by coastal wind farms or solar farms in the desert could defin
Re:Is it effective? (Score:4, Interesting)
I almost forgot, these machines and the clean energy they need could be paid for using carbon credits. Nuclear energy in Northern Illinois (where I live) can be had for about a penny per kWh between midnight and 4 am (when base load is extremely low). So, if they can pull out a ton of CO2 from the atmosphere for 100 kwH of energy, you're looking at between $1-$2/ton in energy costs (capital costs for the equipment needs to be considered, as well as people to maintain everything).
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First, you point out that they can use the excess energy, which would almost be free. However, a big issue with wind power is that gusts cause spikes in the output, which is usually either dumped or the turbines are braked because you can't just dump those spikes in
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Yeah, but how much energy does generating one tonne of CO2 give?
Given approximately 1.5 lb CO2/kWh, somewhere around 1400 kWh.
Probably Not, IMHO (Score:3, Insightful)
Yes.
It will always take more energy to convert from one form of energy to another; the trick is using 'free' energy with minimal impact for a catalyst and accepting that the return is always marginalized. We also get diminishing returns on our attempts to make more efficient systems... the energy to create the systems climbs as the returns on said systems becomes less. Just gotta' accept that part of the game, 'cause you can't not play.
Mine is far more efficient (Score:3, Informative)
It's solar powered. No need to pay any electric bills. Maintenance & care is cheap dirt.
http://pws.byu.edu/tree_tour/images/tree116small.jpg [byu.edu]
Re:Mine is far more efficient (Score:4, Funny)
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Oh dear, I hadn't thought of that.
*poof*
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Trees suck up large amount of CO2 when they're growing and convert it into plant matter. When they reach adulthood, the amount of CO2 they process drops off.
atmosphere processor from LV-426 (Score:2)
Counterproductive (Score:5, Funny)
As a Canadian, I have to say I'm disappointed in my fellow countrymen. Just when you thought global warming would make our climate mildly tolerable, they go and mess it all up.
Thanks, guys. I'm sure you'll regret this in a few months. No, I will not shovel your driveway.
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100 kWh per tonne of CO2 (Score:2)
Since a coal fired power plant produces 100kg of CO2 to produce the electricity to remove one ton, you will have to remove that to, or 1,111kg. And then you will have to store it for a billion years.
Reference point to CO2 emissions (Score:5, Informative)
Assuming that 1 tonne = 1000kg, this machine requires approximately 1 kilowatt hour of electricity to remove 10kg of Carbon Dioxide from the atmosphere. How efficient is this?
From http://www.glumac.com/section.asp?catid=140&subid=152&pageid=564 [glumac.com]
"For home energy use, carbon dioxide emissions vary widely from state-to-state and from day-to-day. The national average is about 1.3 pounds of carbon dioxide for every kilowatt-hour of electricity used in your home."
Not bad. If it really works, you can redirect 10 to 15% of your electricity to achieve Carbon neutrality.
Re:Reference point to CO2 emissions (Score:4, Insightful)
Then only way you can take it completely out of the carbon cycle is to blast it into space on a rocket. Carbon, being the fourth most abundant element in the universe, is everywhere on the planet. Fossil fuels, such as coal and oil, are made of fossilized plants and animals. In other words, fossil fuels are just as much part of the carbon cycle as carbon dioxide, plants, limestone, marble, kittens, and methane. Think about how the carbon got into the coal. It's part of a cycle. A very long cycle.
Natural Gas Processing Plants? (Score:2)
I have always found it curious all the attention to coal-powered generating plants re: CO2, but nobody ever mentions the fact that natural gas processing plants extract--and release directly into the atmosphere--tons of CO2 every year.
Re:Natural Gas Processing Plants? (Score:4, Insightful)
Probably because that gas was coming out anyway, as the wells are tapped for the oil in them. The only thing the natural gas plants do is reduce the overall need for the oil (by taking up some of the load) and convert greenhouse gases into weaker greenhouse gases.
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Coal: 1160 g of CO2/kWh
Gas: 400 g of CO2/kWh
PV Solar: 120 g of CO2/kWh (manufacturing)
Nuclear: 55 g of CO2/kWh
Biomass: -4 kg of CO2/kWh
Of course, nuclear has its own special disposal requirements, but it is less polluting in terms of green house gases.
Source: Wiertzstraat, Wise, Coming Clean: How Clean Is Nuclear Energy? Stichting GroenLinks in EU; Brussels, Belgium. Oct 2000.
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When you burn gas you get less CO2 for the same energy output than you do from coal because part of the reaction is reacting the hydrogen in the gas with oxygen which produces water so gas plants arn't quite so bad for the enviroment.
CH4 + 2O2 -> CO2 + 2H20
Coal however is almost 100% carbon (apart from some minor impurities).
interesting, but... (Score:2)
Re: (Score:3, Interesting)
*snip*
According to these studies, a new coal fired power plant will release between 1.96 (PLC) and 2.09 (DOE) pounds of CO2 per kilowatt hour of operation. For our report, we assume that any given coal-fired power plant will emit 2 pounds of CO2 per kilowatt hour.
A power plant with a one megawatt (1,000 kilowatts) name plate capacity will produce the equivalent of 8,760,000 kilowatt hours annually at full operation -- that is, 8,760 hours multiplied by 1,000. At this ra
I have seen a number of proposals before... (Score:3, Informative)
If I had a penny every time someone says "just absorb it all with lime" I would be able to afford a chocolate bar. Besides which, looking at emissions per kw/h [npcil.nic.in] you had better not use coal or oil to power this, and even with Gas produced electricity the benefit is marginal.
terrible idea (Score:2)
Cheaper way. (Score:2, Funny)
I still think creating a time travel device, going back and assassinating Al Gore and IPCC key members will end this global warming problem.
While we're at it, I hope you won't mind if we put two leads in Col. Korn's head. Later, I'd like to murder Havermeyer and Appleby. After we do those two, we can kill McWatt.
If they want to remove CO2... (Score:5, Insightful)
Goto where the farmers are burning down the rain forests, teach/give/train them how to plant high yield crops and stop them from clear cutting/burning them down. And shock...you'll get somewhere.
Sometimes the most obvious solutions are sitting in front of their faces.
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Go to Neptune, sample the core, and return it to the earth.
I typed it out easily enough, so it must be that simple!
A good laugh (Score:2)
A company could, in principle, contract with an oilsands plant near Fort McMurray to remove CO2 from the air and could build its air capture plant wherever itâ(TM)s cheapest -- China
I had to laugh at that, for once its not because of cheap labour that the jobs are being outsourced.
It does raise the issue however, china is already let off the Kyoto treaty as its considered a developing nation, now are they are going to reap economical benefits of other developed nations by outsourcing their CO2.
Seems like a double win for China for all the wrong reasons.
Space missions (Score:4, Insightful)
expedient and efficient removal of CO2 at atmospheric concentrations could have profound implications in space.
Currently, CO2 is scrubbed using lithium salts, which are not only heavy, but also caustic, and have a limited service life before requiring replacement.
A purely electric, and solid state device capable of continuous operation would allow for superior space vehicle designs which could theoretically operate much longer than currently available ones.
If they discover a way to electronically reduce the carbon dioxide into elemental carbon, things will be even more interesting.
Comment removed (Score:3, Insightful)
Re:Storage Issue (Score:4, Informative)
Hmm, but while you are at it you will hugely acidify the ocean. The chemicals that react with the CO2 only enter the ocean so fast.
The deep ocean trenches may be deep enough to simply liquefy the CO2 so it simply pools on the bottom. This may be more promising. Still not as good as geological storage, however.
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Apart from the surface, the sea has a pretty stable 2 degree (Celsius) temperature, thanks to the inversion point of water. (Ice floats, but ice always forms on the surface -- it doesn't form at the bottom then float up. Water below 2 degrees is less dense than water above 2, so there's this funky convection thing going on that stops the bottom of the sea freezing.
As for pressure, we're talking about very very deep down in the sea, where a human would be pancakified very very quickly.
In these conditions, CO
Caution (Score:2, Interesting)
I really, really wouldn't do all this 'CO2 from the air removing' until we're 100% sure that 1) it causes global warming, 2) global warming is bad and 3) our natural mechanisms are somehow inadequate at the moment. And even then, I mean, sure - put a filter on that chimney, but don't start removing it from places where trees (or plankton) might be hungry for it, making our ecosystem even more unstable.
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1) CO2 does cause heating of the atmosphere. Thats basic physics and is not up for debate.
2) Global warming might not be bad in the long term scheme of things but its bad for the enviroment (and ourselves) as we know it.
3) Given that current natural mechanisms can't cope with the amount of CO2 we're chucking into the atmosphere then its pretty obvious they're inadequate to the needs of clearing up our mess.
And what do we do with the CO2? (Score:5, Interesting)
This extraction of CO2 from the atmosphere is all well and good, but are there any reliable and cost-effective ways to store it or dispose of it?
LImestone (Score:2)
All we need to do is persuade plankton to go on a binge.
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Scrubbing is one thing ... (Score:2, Interesting)
Re:Scrubbing is one thing ... (Score:4, Interesting)
First of all don't diss the benefits of pushing problems off to the future.
I mean the only real problem of CO2 is the cost of energy. We want energy and produce CO2 by running an energy positive chemical reaction (burning). If energy were sufficiently cheap we could simply take the CO2 and transform it into some non-greenhouse form of carbon.
Energy gets cheaper over time, the same amount of CO2 will be less of a problem for future generations with their superior technology and better infrastructure. Besides, it was underground to start with so long as it doesn't leak that seems like a fine place to leave it.
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It doesn't actually seem like an unreasonable assumption - over long timeframes.
What was the cost of 1kWh of energy 10,000 years ago? 1000 years ago? 100 years ago?
Sure, fossil fuels have gone up in cost in the last 50 years, but that is just a recent trend. There is no reason to think that the fusion power of 2050 won't be cheaper than the coal of 1900.
It might also be more expensive, but technology in general has tended to make everything cheaper with time historically. This is just one more thing.
And
Many (Score:2)
I suppose I'm being a troll, but how many of these CO2 removing thingies have to be invented till they exist somewhere outside Slashdot?
Use them on Mars! (Score:2)
Place these things all over the martian surface and make em solar powered!
Great (Score:3, Insightful)
We have found the excuse we need to continue polluting the air. Way to go, humanity!
Some points to consider (Score:3, Informative)
First, this isn't a new idea. Artificial air capture of CO2 has been proposed for some time; a noted proponent of this idea is Klaus Lackner [columbia.edu]. I don't think this new group has made a huge breakthrough in the technology. The basic problem is that it's (a) expensive, and (b) you have to put the carbon somewhere.
As for (a), it's currently cheaper to just capture the CO2 at large point sources like coal plants. On the other hand, that only gets some of the emissions. While coal plants are the most serious source of CO2 right now, adding capture to power plants doesn't capture emissions from cars and other small sources. Still, right now it's easier to just make more fuel efficient cars than try to capture the CO2 they emit.
As for (b), the sequestration problem is shared by any carbon capture technology (air capture or not). The main solutions are to pump it into geological formations in land or under the sea, or to convert it to solid form. The latter is relatively expensive and energy intensive. Storing it in the deep ocean is difficult to do on a large scale. On land there are serious limitations on how fast you can pump CO2 into a formation without pressure fractures and leaks, and even then there is a wide variety of formations whose ability to store CO2 varies dramatically. It requires careful siting, monitoring, etc. and you still have to worry about leaks, not to mention all the legal problems with people worrying about the CO2 acidifying the groundwater and leeching out heavy metals.
That being said, I think this technology definitely needs a lot of R&D aimed at it, because though expensive and difficult, it's a fallback position to reduce CO2 levels if energy efficiency and alternative energy measures don't do enough of a job.
Better article available (Score:3, Informative)
Frankly, I'd rather have trees (Score:4, Insightful)
Gimme numbers, kid! (Score:2)
Re:it this (Score:5, Informative)
Only a lot more efficient. An average tree will use roughly 22kg of CO2 per year. These things are estimated to remove 20 tonnes per year per square metre, so it's in excess of 1000 times more effective. Even after you factor in the CO2 produced to provide the power needed for these things, you're still likely coming out way ahead.
Re: (Score:3, Insightful)
Only a lot more efficient. An average tree will use roughly 22kg of CO2 per year. These things are estimated to remove 20 tonnes per year per square metre, so it's in excess of 1000 times more effective. Even after you factor in the CO2 produced to provide the power needed for these things, you're still likely coming out way ahead.
Only if you plant one tree, and don't use the tree for anything else.
What about planting many more orange and apple trees? What about rubber trees?
We can use trees for more than scrubbing carbon.
Re:CO2 is good (Score:5, Insightful)
A warmer planet is good.
Good for who? Norway? Or West Africa?
A warmer climate leads to more arable land and longer growing seasons.
Depends on where you are. If your plants are temperature limited in a temperate climate, maybe. If they're already in a warm climate, maybe not. And don't forget precipitation. When rain belts get shifted around, a lot of people end up unhappy.
CO2 is good - it is the world's best fertilizer.
This has got to be the most oversold benefit of CO2. CO2 fertilization helps, up to a point, if you have C3 photosynthesizers; C4 plants don't benefit. But direct manipulation FACE experiments show that this effect quickly saturates, and CO2 is often not the rate-limiting nutrient in photosynthesis; often it's water or nitrogen availability. The initial promise of CO2 fertilization hasn't really panned out; see here [sciencemag.org]. It does help, but it doesn't quite help as much as one thinks, and it is often more than offset by negative climate changes.
Of course, all recent evidence points to warming having ended,
I hate to break it to you, but 10 years of below-average warming in a highly noisy system doesn't exactly overturn anthropogenic global warming.
and having been due to natural climate variability and/or solar cycles.
Natural climate variability counts against your claim, not for it. See the above: natural climate variability is quite large on short time scales, which makes short-term trends very unreliable evidence of anything. Over the long term, "natural climate variability" utterly fails to account for temperature trends over the 20th century; the only really long term cycles within the climate system itself are oceans, and the space/time pattern of ocean warming indicates the atmosphere is warming the ocean, not the other way around. Turning to external influences, there are solar cycles. Solar trends have been pretty much flat since the 1950s, and completely disagree with the warming experienced since then. They can account for some of the warming in the early 20th century, but very little of it since then.