Tuesday, 22 September 2009
Researchers say they have found a way to 'green' the Sahara desert with swathes of trees - and put the brakes on climate change at the same time.
Leonard Ornstein, a cell biologist from the Mount Sinai School of Medicine in the United States, and NASA climate modellers David Rind and Igor Aleinov, say that water from the desert's neighbouring oceans could be desalinated and transported inland with pumps and aqueducts.
Heat-tolerant, fast-growing species such as eucalyptus could be planted, with drip irrigation - using plastic tubing to deliver water to roots - to minimise evaporation.
Such forests could cool the Sahara by up to eight degrees Celsius and return rain to the region, they say. Clouds would also help to reflect the sun's rays. The fast-growing trees could absorb eight billion tonnes of carbon dioxide per year - the amount emitted from burning fossil fuels and forests today - and could do so for decades.
The price tag of US$2 trillion a year is not low. But Ornstein and colleagues say that after several decades the forests would provide a sustainable source of firewood, making them carbon neutral.
Drawbacks of the increased moisture are the possibility of more locust plagues and the prevention of iron-rich dust blowing into the Atlantic Ocean where it feeds sea life, the researchers say.
Nevertheless, the idea "is incredibly important and definitely worth taking seriously," says atmospheric scientist Richard Anthes, president of the University Corporation for Atmospheric Research.
SciDev.net
The Sahara isn't just a giant dead zone: like just about every other place on earth, it's a thriving ecosystem that others are deeply interdependant upon.
ReplyDeleteThis strikes me as total hubris. "It looks like a bunch a sand to me: let's go fuck it up! We sure know what we're doing! Yep!"
well, that's a valid point. However, our current system fucks up a lot of more productive and more biologically rich ecosystems, closer to home and covered with extremely valuable biomass. Personally I think we should take advantage of the one supremely abundant resource the desrt has: sunlight. See the previous graphic. One twentieth of the surface area of the sahara could power the entire world's daily energy consumption in about six hours, if we put in the infrastructure.
ReplyDeleteLong ago you said something that I now realize shows me that you really do respect systems thinking: you were talking about extinction. You said that all living things are interdependant and that we're extinguishing species so fast, what happens if we destroy one that we depend upon for our lives, through some ramification too complex to understand until it's too late.
ReplyDeleteI'm not saying I accept that explicitly, but I suspect that there are microbial interdependencies that are more important than most, if not all, kindom animilia connections. At least with regard to human existance.
That's why I'm deeply suspicious of a plan like this: a specific ecosystem like the Sahara is probably to sole source of a large number of unique bacteria and yeasts, etc. that are globally critical. But because it looks like a bunch of dead sand, we think it won't matter if we make it green, because we like green things better than we like sandy things.
That's probably just as dangerous as clear-cutting the Amazon.
I doubt very much it is as dangerous as clear-cutting the Amazon, simply because the Amazon holds perhaps 5,000 TIMES as many species as does the Sahara, and therefore the possibilities for complex ramifications are greatly enhanced. However, your basic point is well taken; in general, I agree with the premise. More so, I dare say, than you yourself do: I would like to see human manipulation of all remaining wilderness to cease, and the reversion of much altered landscape to wilderness. I don't accept economic progress as justification for poorly managed, irresponsible resource extraction. Period.
ReplyDeleteHowever, that isn't possible. We have, unfortunately, been faced the real and immediate necessity of changing our global energy infrastructure. And with doing whatever we can to mitigate the damage already done. That's going to disrupt new ecosystems, ironically and counter-intuitively. What we can hope to do is switch up our areas of impact so that landscapes which are "most valuable" in terms of biodiversity and carbon-absorption are spared and those which we more fully utilize are those with the least utilitarian value.
I have many ideas along those lines, if you are interested.
ps forgot to mention,
ReplyDeleteit has nothing to do with liking green things more than sandy things, unless you mean "like" in the biological sense that we depend on them for survival. Personally I doubt that desalinization for irrigating an area as large as they are talking about is sustainable in any sense of the world. However, it is a fact that we have lost about 30-45% of the world's tree cover in the last two centuries due to cutting, and will lose a great percentage more rapidly yet due to climate change. We need to plant trees, and we need to plant them fast. Maybe the Sahara isn't the best bet as to a location.