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. 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:
(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?
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?
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.
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…
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?
I was just reading that it takes one tree planted to counteract 100 gallons of gasoline
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?
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
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, 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.
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…
The US produces about half of greenhouse gas emissions, the world makes about 7 and we make about 3.2
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?
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.
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.
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
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
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.