I suspect that the second worst idea in the world is to attempt to control global warming by means of geoengineering.
I sometimes think about geoengineering when I walk to work. (Don’t you?) I see the trees around me, just beginning to senesce for autumn, and I think about the (to me) incalculable tons of carbon dioxide that they remove from the air, much of which they store long-term in wood and roots. They do it for free. But geoengineers have a different solution. It is to build “artificial trees” that cost a lot of money. These “trees” are basically carbon dioxide filters on top of poles.
According to a 2009 article, “Each synthetic tree could capture up to 10 tons of CO2 a day, which is thousands of times more than a real tree. Each tree would cost around $24,400, and a forest of 100,000 of them could be constructed within the next couple of decades using existing technologies.” Doesn’t this sound exciting? Only $2.4 billion. Of course, real trees are free, unless you insist on planting certain trees in certain places. The article continues, “The trees would have a special synthetic filter that absorbs carbon dioxide. When the filters had absorbed their load of CO2 they would be replaced with new filters and the old ones would be stored in empty gas and oil reservoirs, such as depleted oil wells in the North Sea.” It occurred to me that the $24,000 price tag did not include removing and storing old filters, and replacing them with new ones. And you can’t just drop something down into a North Sea oil well. This sounds to me like someone wanting to sell huge expensive devices and using the environmental playing-card as a way to sell them.
The only thing that may be worse than this type of geoengineering is to launch hundreds of thousands of mirrors into space, between the Earth and the Sun, to cast a partial shadow on the Earth. There is a reason that the price tag for this geoengineering solution is generally not mentioned.
As I explained in my book Green Planet, trees do lots of things that keep the Earth alive. A tree produces oxygen, absorbs carbon dioxide, creates cool shade, reduces floods, recharges ground water, holds down and enriches the soil, and many other things. An artificial tree does only one of those things.
Geoengineering scenarios sound like something from the old Outer Limits TV shows. It also sounds like the kind of solution that a Democrat would come up with: a big, expensive government solution. Except that it was the Republican president George W. Bush that, according to this article, promoted the idea of space mirrors.
I prefer “no-regrets” solutions over geoengineering solutions. If we allow trees to grow, and maybe plant some extra ones, we will have good results; this has been assured by hundreds of millions of years of evolution. If it turns out global warming is not a problem, the trees will perform other valuable services. No regrets. But if it turns out that global warming is not a problem (a virtual impossibility), then we will have wasted billions if not trillions on geoengineering fiascos. Lots of regrets.
Of course, the worst idea is to go along with the Republican Party and pretend that global warming is not occurring.