photo: Paul Falardeau via flickr.
For some reason (frankly, entirely lost on me) the idea of artificial trees to remove CO2 from the atmosphere seems to grab people's imagination in a way other geoengineering schemes don't. Well, over at Yale e360 there's a good piece that goes into the pros (artificial CO2 scrubbers could work with low chance of unintended consequences) and cons (it's gonna be really expensive) of deploying them on a wide scale:There are a number of different ways of using these artificial trees -- which won't look much like trees, despite some artists' conceptions -- and the original piece details different methods being researched, but it's really other aspects of this that grab me.
100 Years of Deployment Needed to Start to See Desired Effect
First of all, though the tech has been tested on a small scale, we're probably five years away from a small scale deployment and two decades from wide scale implementation.
And then, if the high costs can be overcome (more on this further down...), according to oceanographer John Sheppard, who led the Royal Society's recent examination of different geoengineering schemes, you'll need "100 years of deployment before you start to see the effect your looking for."
If there ever was a quote that places this into the Plan C category of emission reductions, I'm not sure what it would be. Not that it shouldn't be investigated, but don't hold out hope that this is an emergency response to emission reductions -- more like a long term strategic response to supplement other reduction strategies.
$20 Trillion per 50ppm of CO2 Removal
Which brings us to cost: Author David Biello reminds us that the Royal Society estimates that the infrastructure required to deploy the millions of the these CO2 scrubbers required to 650 billion tons of carbon from the atmosphere by 2100 to keep CO2 to 450 ppm (not the increasingly recommended 350 ppm) will be "as large, or larger than, that of the current fossil fuel extraction."
James Hansen estimates that to cost be 50 ppm of CO2 removal to be in the range of $20 trillion. Yes, trillion.
Lowering Emissions Must Be Primary Goal
Which all means, to defer to the Royal Society again, that the safest and most predictable method of reducing greenhouse gases is (drum roll) to not emit them in the first place. And the first line of attack in that : Energy efficiency, renewable energy, stopping deforestation.
Read the entire original: Pulling CO2 From the Air: Promising Idea, Big Price Tag
Forest of 100,000 Artificial Carbon-Capturing Trees Proposed in UK
Artificial Trees: Could They Be Better Than the Real Thing?
Royal Society Says Geoengineering Humanity's Last Hope - But Emission Reductions Must Be Top Priority