Since most of the world seems unable or unwilling to both reduce consumption of and find alternatives to carbon dioxide producing fossil fuels, scientists are now forced to entertain bizarre ways of counteracting its effects and delaying the inevitable.
Much like a chronic overeater who would treat his obesity with liposuction instead of proper eating and exercise, this article over at Wired has a pretty good round up of some of the ideas being bandied about to help us have our petroleum and burn it too.
There's the man-made "volcano" that shoots gigatons of sulfur high into the air. The space "sun shade" made of trillions of little reflectors between Earth and sun, slightly lowering the planet's temperature. The forest of ugly artificial "trees" that suck carbon dioxide out of the air. And the "Geritol solution" in which iron dust is dumped into the ocean.
Discussion below.
The Sulfur Shading Effect
I first read about this in a Rolling Stone article about Edward Teller. In the news today, the lack of aerosols in the atmosphere contributed to the hottest winter ever in the northern hemisphere in recorded history. Replacing those with something that shades the earth, like sulfur, would ostensibly counteract the greenhouse effect of CO2 by "tinting" the windows of our Gaian greenhouse. The sulfur can be shot into the stratosphere in cannon shells, or by some other means in quantities sufficient enough to shade the planet, given we use enough of it. One drawback of sulfur is acid rain, so perhaps another compound should be used. In discussing this with a friend tonight, he suggested silver nitrate. Does anyone know whether this is doable/cost effective? Also, will shading the planet reduce the ability of solar cells to produce electricity?
Iron Seeds
This idea has more potential, as it uses the earth's natural processes for removing carbon. The basic idea is to "seed" the ocean with iron to promote plankton growth. Plankton is currently responsible for over half the carbon sequestration from the atmosphere, so it makes sense to explore this possibility. The idea is that iron encourages plankton growth which uses ocean-based CO2 to produce its exoskeleton. The ocean then replenishes the lost CO2 by absorbing it from the atmosphere. One major issue here is that if the CO2 in the oceans reaches too high a level, the ocean becomes acidic, and the plankton doesn't grow. Seeding the ocean will need to be done in concert with CO2 reduction to be effective over the long term, but this sounds like a pretty good idea. The proponents claim 1 ton of iron removes 100,000 tons of CO2, which sounds high to me. Can something like this really work? What effect will it have on the oceans? Can it simultaneously help replenish fish stocks which have been decimated through over fishing?
Solar Shades
One scientist suggests launching trillions of Frisbee-sized sunshades into orbit to shade the planet. It requires 20 million rockets to deploy that many sunshades, and what kind of interference with satellites and other launches would it cause? How much extra global warming and reduction of the ozone layer would that create? This one struck me as untenable.
Artificial Trees
I think this is another undoable one. The idea is to build structures which capture the CO2 from the air and remove it mechanically, but it requires somewhere to store the CO2 after it has been captured. Artificial carbon sequestration is full of both known and unknown environmental impacts. For example, sequestering the CO2 in the ocean contributes carbonic acid to the ocean, the effects of which are unknown at the depths at which the sequestration takes place, although it is known to prevent plankton growth at the surface. Sequestration underground has the potential of leaking either slowly (negating its effect) or catastrophically (possibly resulting in the suffocating deaths of humans and animals).
In approaching solutions global warming, we're going to need a multi-pronged strategy. It's a good exercise to think outside the box, as these proposals have done, even if some sound a little crazy.