# Can we remove greenhouse gases already in the atmosphere **URL:** \ **Category:** Factual Questions\ **Created:** [April 19, 2006, 11:33pm UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386 "2006-04-19T23:33:32Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 19, 2006, 11:33pm UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/1 "2006-04-19T23:33:32Z")
I have heard of scrubbers which are designed to convert greenhouse gases into something different (or to just sequester them, I don’t know which), but they seem really inefficient and expensive. Do we know of any way to remove greenhouse gases from the atmosphere? I’ve heard agriculture doesn’t work either as trees & plants just re-release the gases back into the atmosphere if they get too much of them. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 20, 2006, 12:53am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/2 "2006-04-20T00:53:41Z")
> [@Wesley Clark](#): > > I have heard of scrubbers which are designed to convert greenhouse gases into something different (or to just sequester them, I don’t know which), but they seem really inefficient and expensive. Do we know of any way to remove greenhouse gases from the atmosphere? I’ve heard agriculture doesn’t work either as trees & plants just re-release the gases back into the atmosphere if they get too much of them. Here’s a Reason article that touches briefly on the question: [http://reason.com/9711/fe.benford.shtml](http://reason.com/9711/fe.benford.shtml). There are two caveats about it. First, I couldn’t find a date on the article, but I think the URL is telling us it’s from November 1997. So it’s not exactly new material. Second, Reason is a very libertarian-oriented magazine, and they have a bit of an axe to grind on climate change issues. The gist of this article seems to be, “Climate change mitigation is a snap. Let’s burn all the fossil fuels we want, and if it turns out there’s a problem, no biggie!” Anyway, here’s the highlights: > [@Reason](#): > > The simplest way to remove carbon dioxide, the main greenhouse gas, is to grow plants–preferably trees, since they tie up more of the gas in cellulose, meaning it will not return to the air within a season or two. Plants build themselves out of air and water, taking only a tiny fraction of their mass from the soil. Forests, which cover about a third of the land, have shrunk by a third in the last 10,000 years (though they have grown over the last half-century in the United States, mostly due to market forces). > > Like the ocean, land plants hold about three times as much carbon as the atmosphere. While oceans take many centuries to exchange this mass with the air, flora take only a few years. > > … > > Trees soak up carbon fastest when young. Planting fast-growing species will give a big early effect, but what happens when they mature? Eventually they either die and rot on the ground, returning nutrients to the soil, or we burn them. If this burning replaces oil or coal burning, fine and good. Even felling all the trees still leaves some carbon stored longer as roots and lumber. Buildings can hold lumber out of this cycle for a century or so. > > About half the U.S. carbon dioxide emissions could be captured if we grew tree crops on economically marginal croplands and pasture. More forests could enhance biodiversity, wildlife, and water quality (forests are natural filters); make for better recreation; and give us more natural wood products. Even better, one can do the cheapest part first, with land nobody uses now. This would cost about $5 billion a year, and a feel-good campaign would sell easily, with merchants able to proclaim their eco-virtue (“Buy a car, plant a grove of trees”). (hope that falls within the fair use guidelines…) I’ve been wondering the same question as the OP for a while myself, but haven’t seen anything else really addressing the issue other than the plant-trees or fertilize-the-oceans solutions discussed in the article above. Anyone else? ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [April 20, 2006, 1:01am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/3 "2006-04-20T01:01:05Z")
Fertilizing the oceans seems risky due to unintended consequences, but seriously how much would it cost for us to start planting trees on the scale which would seriously curb greenhouse gas levels? And where do we put them once we cut them down to grow new trees? ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 1:13am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/4 "2006-04-20T01:13:57Z")
You’d assume that finding ways to combine genetic engineering with this would be researched. If we could improve photosynthesis efficiency we could find cheaper food and fight global warming at the same time. Photosynthesis is only about 5% efficient by nature, making it better would help clear out some CO2. [http://www.fao.org/docrep/w7241e/w7241e05.htm](http://www.fao.org/docrep/w7241e/w7241e05.htm) ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 20, 2006, 1:22am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/5 "2006-04-20T01:22:59Z")
> [@threemae](#): > > Fertilizing the oceans seems risky due to unintended consequences, but seriously how much would it cost for us to start planting trees on the scale which would seriously curb greenhouse gas levels? > > And where do we put them once we cut them down to grow new trees? And secondly, it’s my understanding that fertilizing the oceans doesn’t lead to any long-term sequestering of C02 as its proponents seem to suggest. The Reason article says $5b/year, but sadly doesn’t go into much detail on where they got this number from, or what it represents. But as for where we can put them - anywhere, I guess. Bury them, dump 'em in the deep ocean, leave 'em in northern Greenland… ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [April 20, 2006, 1:41am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/6 "2006-04-20T01:41:23Z")
Well, I just did some back of the envelope computations on this by looking at bulk paper on the web. First, I’m sure the actual number would be orders of magnitude lower than this, but by Googling for bulk paper that came in 300 lb rolls, I calculated that we would be able to cancel out all of our CO2 annually with about $5 trillion dollars, or around two thirds of our GDP. Of course, we wouldn’t need to process this stuff into paper, just bury the wood. $5 billion seems laughably small, but maybe $100 billion with the appropriate scale? ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 1:45am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/7 "2006-04-20T01:45:26Z")
I was just reading that it takes one tree planted to counteract 100 gallons of gasoline [http://www.angelfire.com/fl4/globalcooling/](http://www.angelfire.com/fl4/globalcooling/) That works out to about 2000 pounds of CO2 sequesterd by each tree. Considering that in the US we produce 3.2 billion tons a year that means we’d have to plant 3.2 billion trees a year. I don’t know if we could do that on $5 billion a year. Plus where will we get the nitrogen, phosphorus and potassium to grow the trees? ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 1:50am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/8 "2006-04-20T01:50:24Z")
> [@Do Not Taunt](#): > > And secondly, it’s my understanding that fertilizing the oceans doesn’t lead to any long-term sequestering of C02 as its proponents seem to suggest. I’m not sure anymore. I remember this being a big idea, then someone found out that there was a second, more expensive limiting nutrient in the growth of algae and iron alone wasn’t enough to cause growth to fight CO2. However experiements have found that Iron alone works, so I’m not totally sure. [http://archives.cnn.com/2000/NATURE/10/12/ocean.carbon.ap/index.html](http://archives.cnn.com/2000/NATURE/10/12/ocean.carbon.ap/index.html) [http://www.futurepundit.com/archives/002056.html](http://www.futurepundit.com/archives/002056.html) ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 20, 2006, 1:55am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/9 "2006-04-20T01:55:55Z")
> [@threemae](#): > > Well, I just did some back of the envelope computations on this by looking at bulk paper on the web. > > First, I’m sure the actual number would be orders of magnitude lower than this, but by Googling for bulk paper that came in 300 lb rolls, I calculated that we would be able to cancel out all of our CO2 annually with about $5 trillion dollars, or around two thirds of our GDP. > > Of course, we wouldn’t need to process this stuff into paper, just bury the wood. > > $5 billion seems laughably small, but maybe $100 billion with the appropriate scale? Sorry, I misquoted the article a little bit. :smack: $5B was for half the US emissions. I’m not sure what percentage of CO2 emissions the US is responsible for, but given our share of Gross World Product, between a fourth and a fifth seems reasonable. So where I said $5B before should have been more like $50B. Also factoring in a decade of growth, and your $100B guess seems to be in the same ballpark as the Reason number. Also, $5T is more like 40% of US GDP.[/nitpick] Oh, hey, and on preview, **Wesley Clark** , I’ll add to your back of the envelope calculation. This website, [SCFC Tree Spacing](http://www.state.sc.us/forest/nurspa.htm), leads me to believe 500 trees/acre is a reasonable density, so your 3.2 B trees/year would require 6.4 M acres/year, which conveniently is about 10000 sq mi. That’s more in the realm of feasibility than I would have guessed. ---
**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\ **Post date:** [April 20, 2006, 1:58am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/10 "2006-04-20T01:58:30Z")
> [@Wesley Clark](#): > > I’m not sure anymore. I remember this being a big idea, then someone found out that there was a second, more expensive limiting nutrient in the growth of algae and iron alone wasn’t enough to cause growth to fight CO2. However experiements have found that Iron alone works, so I’m not totally sure. > > [http://archives.cnn.com/2000/NATURE/10/12/ocean.carbon.ap/index.html](http://archives.cnn.com/2000/NATURE/10/12/ocean.carbon.ap/index.html) > > [http://www.futurepundit.com/archives/002056.html](http://www.futurepundit.com/archives/002056.html) The objection I recall was not that iron was insufficient to stimulate algal growth, but that the effect was short-term. Rather than sinking the ocean bottom and sequestering the carbon for good, the algae had the nerve to enter the food chain and cough the CO2 back into the atmosphere within a few months. I’ll see if I can dig up some cites, but I gotta run right now… ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 2:00am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/11 "2006-04-20T02:00:41Z")
The US produces about half of greenhouse gas emissions, the world makes about 7 and we make about 3.2 ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [April 20, 2006, 4:37am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/12 "2006-04-20T04:37:22Z")
Well, certainly the trees are a better way to go about it, but I figured I’d look at the paper for the worst-case scenario because I couldn’t find out how much it costs to plant a tree. At any rate, I did find out that our national forrest industries currently plant about 13 million trees a year (and by plant I assume they mean make growing, stable trees) so this means about a 500 fold increase in tree planting. Also, presdumably we could cut down rainforest trees and regrow those more quickly than typical, high latitude forests, right? ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 4:56am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/13 "2006-04-20T04:56:31Z")
[http://www.dnr.state.mn.us/areas/forestry/mankato/pl\_tree\_smn.html](http://www.dnr.state.mn.us/areas/forestry/mankato/pl_tree_smn.html) $300-400 per acre, 6.4 million acres so that would add up to 192-256 billion a year just to plant new trees to take care of US greenhouse gas emissions. And that is just to cover new emissions, not to remove old emissions. It would be alot cheaper to just retrofit coal plants with some kind of CO2 sequestering devices. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 4:58am UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/14 "2006-04-20T04:58:55Z")
My calculations are all wrong. It is closer to 2.24-2.56 billion a year to plant 6.4 million acres of trees. That is perfectly affordable. ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [April 20, 2006, 12:24pm UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/15 "2006-04-20T12:24:55Z")
The problem with non-natural CO2 sequestering (such as CO2 scrubbers) is that the energy needed to generate the chemicals needed produces more CO2 than you end up sequestering. Essentially it will take a lot of energy to capture CO2 - probably only the sun through photosynthesis can actually do it. Far better is to stop the CO2 being released in the first place ---
**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\ **Post date:** [April 20, 2006, 8:32pm UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/16 "2006-04-20T20:32:40Z")
Hell, even at $200 billion a year it sounds like a virtual bargain if it can really delay, stop, or even reverse global warming. Wikipedia says we use 360 million gallons of gas a day, so planting trees to offset that gas might cost about a dollar or two a gallon? Not cheap, but perhaps cheaper than the alternative. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [April 20, 2006, 8:55pm UTC](https://boards.straightdope.com/t/can-we-remove-greenhouse-gases-already-in-the-atmosphere/353386/17 "2006-04-20T20:55:33Z")
> [@threemae](#): > > Hell, even at $200 billion a year it sounds like a virtual bargain if it can really delay, stop, or even reverse global warming. > > Wikipedia says we use 360 million gallons of gas a day, so planting trees to offset that gas might cost about a dollar or two a gallon? Not cheap, but perhaps cheaper than the alternative. The climate models I’ve seen show that a 3 C warming and the melting of Greenland would put Florida and Louisiana underwater. COnsidering how much damage things like Katrina and 9/11 did, it is easy to see that unrestrained global warming could easily do tens to hundreds of trillions of dollars worth of damage to the economy. At the very least the cost of building competent levees around coastal cities to prevent flooding would cost hundreds of billions, if not trillions to accomplish. Its sad how lazy we really are about this threat, it makes 9/11 look weak by comparison, like comparing a fistfight to a world war. $200 billion would do tons to stop global warming. That could build 50-100 nuclear plants, retrofit most coal & oil plants to sequester CO2 instead of dump it into the atmosphere, plant enough trees for 100 years, invest in R&D for clean & renewable energy (I think the federal budget for R&D for renewable energy is only $771 million a year), etc. I hope this is true too [http://www.sinodaily.com/news/energy-tech-05zzzzzzzzc.html](http://www.sinodaily.com/news/energy-tech-05zzzzzzzzc.html) That, and Vivian Alberts new method of solar energy may mean we are heading in the right direction on this problem. If Alberts starts selling his solar panels in the US I’m going to get my home fitted for them.