1. Galactic Sunshades
If the sun is too bright, put on shades. That's pretty much what Roger Angel, director of the Centre for Astronomical Adaptive Optics at the University of Arizona, is proposing. A leading scientist in the field of astronomical optics, Angel envisions some 16 trillion transparent film disks, each 0.005 mm. thick, 61 cm. wide, and about a gram in mass - think of giant, feather-light pizzas - arrayed 1.5 million km. above the planet. They'd form a cylindrical cloud, 90,000 km. long, between the earth and sun, and block just enough sunlight to help reduce global temperatures. One big question: Can we come up with the $5 trillion this plan would cost?
2. Protective Blanket
Paul J. Crutzen, a scientist at Max Planck Institute's atmospheric chemistry department in Germany, and co-winner of the 1995 Nobel Prize in Chemistry for his work on the ozone layer, last year proposed a radical geo-engineering solution as an urgent measure to slow down extreme warming: Thousands of heavy-artillery shells filled with fine sulphur powder would be fired into the stratosphere, where they'd explode and create a blanket of dust around our planet. (The sulphur might also be delivered in special balloons or rockets.) The theory is that such a shield would reflect a little solar radiation back into space, thus cooling the earth. It's based on the fact that global temperature drops after a volcanic eruption spews dust into the atmosphere.
3. Muscling Up the Clouds
John Latham, a scientist at the National Center for Atmospheric Research in Colorado proposes what may be one of the more practical solutions: Spraying fine droplets of seawater into the atmosphere to bulk up the marine stratocumulus clouds (the big, fluffy ones) that are thought to reflect sunlight back into space. Adding just 2% to the clouds' reflectivity, Latham argues, might be enough to counteract the warming effect of a doubling of CO2 in the atmosphere. How might this be done? A global fleet of ships would ply the oceans, blasting mist into the air like so many giant nasal-spray bottles.
4. Scrub it Clean
Removing CO2 from the air is nothing new. For decades, submariners and divers have been using devices known as "rebreathers" to do just that. Using a similar principle could scrub millions of tons of CO2 from the atmosphere. David Keith, Canada Research Chair in Energy and the Environment at the University of Calgary, has built a prototype scrubber that draws air in, then passes it through the chemical Na2OH. Since his machine soaks up only a minute amount of CO2, Keith says it would be too expensive to use devices such as these to capture unwanted gas at power plants. However, it might be a cost-effective way to manage emissions from small sources such as aircraft or cars.
5. The "Geritol Solution"
The tiny marine algae of the world's oceans absorb enormous amounts of CO2 from the air during photosynthesis. However, there are large areas of the oceans that are only sparsely populated by algae; these places lack the iron necessary for the plants to flourish. So, in the early 1990s, the late oceanographer John Martin, of Moss landing Marine Laboratories in California, proposed creating algal blooms to absorb additional CO2 by dumping dissolved iron into barren areas of the sea. Such experiments have been done several times since, and the technique has been dubbed the "Geritol solution," after the popular iron supplement. The results have been mixed, however, and many scientists are concerned, if done on a large scale, it could upset the ocean's natural balance.
[Reader's Digest, March issue]
Yet still, with all these proposed "quick fixes", the best way to deal with climate change is to stop the burning of fossil fuels to further reduce greenhouse gas emissions.
ayown.
