Fighting Global Warming: Artificial Trees and Slime-Covered Buildings

By Eliza Strickland | August 27, 2009 3:06 pm

artificial treesThe most practical and immediate steps we can take to slow global warming may be lining roadways with towering “artificial trees” and covering buildings with algae bioreactors, argues a new report from Britain’s Institution of Mechanical Engineers. The group believes that geoengineering (a broad term for climate-altering technologies) may be necessary to reduce carbon dioxide levels immediately, while governments continue to bicker about how to transition to a low-carbon future. “Geo-engineering is no silver bullet, it just buys us time,” said Tim Fox of the IME, who led the study [The Guardian].

Fox says the study (pdf) looked for techniques that could be rolled out with existing technology. The IME’s first suggestion is to construct hundreds of thousands of “artificial trees”, essentially building- or goalpost-sized structures through which the wind blows. As air passes through them, the “trees” extract CO2 from it for later sequestration [The Register]. The fake trees are intended to be much more efficient at absorbing CO2 than real, biological trees, with current designs estimated to remove one ton of CO2 from the air daily. But even if the devices could be made ten times more efficient, the study found that 100,000 fake trees would be required to absorb the CO2 emissions from all the cars and trucks in the United Kingdom.

algae buildingsThe second proposal calls for making cities truly “green” by attaching tubes filled with algae to the sides of buildings. “Algae is a naturally-occurring eco-friendly biomass that tends to have a high level of CO2 use in photosynthesis,” said Tom Bowman of IME. The algae that grows can be collected and turned into charcoal, which can be buried so that the CO2 it has captured is locked away from the atmosphere [The Guardian]—if everything works according to plan. However, the study notes that such bioreactors are still expensive, and that it would be challenging to add them to existing buildings. At this point, the study, says, such technology is in the “conceptual stage,” but given its potential benefits it deserves further study.

The engineering group isn’t the first to evaluate the plausibility of different geoengineering schemes. The IME’s study professes to be a realistic look at the potential of implementing various technologies, and specifically excludes some of the more dramatic geoengineering suggestions, like placing giant sunshades in space or continuously sprinkling sun-blocking particles in the upper atmosphere. While such radiation-managing techniques may be more effective, the study says, they also carry more risks; if a large-scale project abruptly failed it would result in sudden, extreme warming, and such systems would also do nothing to change the acidifying effect of carbon dioxide in the oceans. That’s why the engineers are supporting technologies that capture and store the excess CO2 already in our atmosphere. But the IME report seems unrealistic in its own way, in that it imagines a swift worldwide adoption of unfamiliar technologies.

The IME has one more suggestion that does dabble in radiation management. Painting rooftops white in cities across the globe wouldn’t reflect enough sunlight to have a significant impact on global warming, but it could reduce the “urban heat island” effect, in which acres of dark buildings and pavement cause cities to heat up more than their surroundings. Reflective rooftops would cool buildings and could reduce energy used in air-conditioners by between 10 and 60 per cent, the report says [The Times].

The Institution’s report is unlikely to be the last word on geo-engineering. Next week the Royal Society will publish a much broader study that reviews all the options – including the most outlandish, science fiction ideas like sun shades in space – and focussing on the ethical and political problems posed by tampering with the planet’s climate systems [BBC News].

Related Content:
80beats: Obama’s Science Adviser Kicks Up a Fuss Over Geoengineering
80beats: Ancient Agriculture Trick, Not Hi-Tech Engineering, Is Best Climate Defense
80beats: Meet the Black Phantom, the Huge Microwave Oven That Fights Climate Change
DISCOVER: 5 Most Radical Ways to Squelch a Climate Crisis (photo gallery)

Image: Institution of Mechanical Engineers

CATEGORIZED UNDER: Environment, Feature, Technology
  • Neil Wyatt

    This all seems rather silly and attention seeking, especially since man made CO2 is so insignificant.
    The Gore powerpoint horror show we brainwash our kids with showed temperature going up like a rocket with CO2 and yet it’s been looking quite autumnal today. (27th August)
    There was a Barbeque Summer this year, so long as one held it indoors and as for 2009 being one of the hottest years’ on record…well just forget it.
    Mind you, that’s weather & it’s climate we are supposed to pay up now for and get the benefit 40 years down the line. Some people just don’t know when they are being had!
    Propaganda is alive and well today, just like the record number of Polar Bears in the Arctic.
    I just can’t wait for the next series of ‘Ice Road Truckers!’

  • Russ

    Wouldn’t tall buildings be the most expensive place to put algae farms? I can think of quite a few other places that would be much cheaper.

  • Jacob

    So Neil, who is behind all this propaganda? What do they hope to gain from it?

  • Eco Science Fair Projects

    My science fair projects students found this news article very interesting. Our question is how are the “artificial” trees to be constructed and how what type of carbon foot print will they create during their manufacturing process?

  • Daniel J. Adnrews

    Indeed Neil, there is propaganda and you’ve swallowed it hook, line and sinker. Check out what real climatologists are saying with the “Start Here” section of ( You can also go to which lists the most common myths/lies/misunderstandings. This site is recommended by climatologists.

    Talk show hosts, political think-tanks and political blogs have been lying to you (e.g. manmade CO2 being insignificant…compared to what? Volcanoes? Nope:

    You imply you know the difference between weather and climate, but if you really did you wouldn’t used the BBQ summer comment. So check where Peter Sinclair gives explains the difference between climate and weather.

    If you’re going to contradict 97% of climatologists (, and every major scientific organization around the world you should at least make an effort to understand the very basics.

    If you’re not a troll and are seriously interested in what the science actually says (i.e. not in what some political ideologue on either side says), then check those links above. They try and link to the original work/data so you can see for yourself. Also Sinclair has a number of youtube videos now and those are a good place to get basics as well (he also references original sources where possible). The good news is that even a basic amount of education on the topic is enough to show you that most of the denier memes are lies.

    If you still have questions come on over to the comment sections in realclimate, ill-considered, or greenfyre, or tamino open mind and ask there (don’t ask here as you’ll not likely get the responses you need to learn). Come in with an open mind, do not make claims that you can’t back up with evidence (like you did here), and knowledgeable commenters will be happy to help you. Happy researching.

  • Neil Wyatt

    Who is behind the propaganda: Scientists and Journalists with grants and bonuses to produce propaganda.(Sensationalism sells papers too)
    Who pays: The tax payer, you and me via governmental sponsors to ensure a nice carbon meter earner for as long as this scam will last.

    300 years of coal under our feet, tons of rubbish that could be burned as fuel instead of methane leaking land fill we pay tax on and locally produced biomas we produce so little of.
    Instead we import windmills…So much for the carbon footprint but just think about that green energy and the green high tax that goes with it.
    The choice for the future: Poor and cold or well off and warm!

  • Matt

    I’m all for trying to find different sources of energy, but according to my biology textbook for college, natural recycling of CO2 puts at least 85 billion tons of carbon into the atmosphere, and has been doing so for the past 250 million years or so. Wikipedia says that all the human activities in the world combine to about 30 billion tons of carbon released into the atmosphere a year. So basically, I’m supposed to believe that 250 million years of 85 billion tons a year didn’t destroy the earth, but 50 years of 30 billion tons is going to. Doesn’t make a lot of sense to me.

  • Paul Bates

    Interesting ideas. I don’t think I’d like to cover my house with algae though if that’s what was called for. I think we’ll get the most bang for the buck right now with more efficiency of the structures and businesses that are already there.

  • Paul

    Hi Matt,

    The point about 85 billion tons of carbon is that it is in balance. The global ecosystem does indeed produce 85 billion tons of carbon but it also absorbs 85 billion tones of carbon. The system is therefore has no net gain. We now release 30 billion tones of carbon into the atmosphere, there is a net increase in carbon which is also increasing each year. This carbon dioxide changes the net radiative balance in the atmosphere and temperatures/climates change.

  • greenfyre

    @ Neil
    “Who is behind the propaganda: Scientists with grants and bonuses to produce propaganda.”

    So you obviously have no background whatsoever in the sciences, and no idea how they are funded. Good to get that on the table.

    “Who is behind the propaganda:”

    Instead of asking rhetorical questions why not actually do the internet search to find facts, not Denier innuendo?
    “Where there’s smoke, the climate change Denial lobby ”

    “Who funds them”

  • Craig

    To Daniel J. Andrews:

    Citing clearly biased websites and blogs is hardly a convincing mode of debate.

    In addition – there is plenty of counter evidence to global warming. Neither side is conclusive, certainly, but your mentality that everyone who’s skeptical is a loony is just as concerning as you seem to think theirs is. In the last century or so, sea levels and temperatures have been rising, but, put in perspective, it could easily be part of a reoccurring cycle that has been observed throughout natural history by scientists.

    Debates are fun and all, but referencing sources that would be considered invalid in a middle school research paper is not a good place to start.

  • artificial trees girl

    With the threat of global warming looming, i am a huge advocate of artificial trees, but i’m not sure i 100% agree with this article. Having said that, i think some of the points are valid and i would personally like to see more research on this subject.


  • Sklep

    Undeniably believe that which you said. Your favorite reason appeared to be on the web the simplest thing to be aware of. I say to you, I definitely get annoyed while people think about worries that they plainly do not know about. You managed to hit the nail upon the top and also defined out the whole thing without having side effect , people can take a signal. Will likely be back to get more. Thanks

  • Paul

    I find it very hard to believe these are the “most practical and immediate” steps that can be taken. In particular, reducing coal use, or capturing CO2 from large stationary sources, are likely to be much cheaper per unit of CO2.


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