Gregory Benford is a professor of plasma physics and astrophysics at the University of California, and received his PhD in 1967. He's been an adviser for NASA, the Department of Energy and the White House Council on Space Policy, and attended the first NSF global warming summit back in 1992. He's also a writer, and has bashed out some of the best hard sci-fi novels of the modern age, including Timescape, Cosm, and the Galactic Center Saga which spanned six books from In The Ocean Of Night to Sailing Bright Eternity.
This experience of painting mind-expanding mental images with strict scientific accuracy allowed him to give a very complete picture of the challenges of global warming, free of the usual distortions, half-remembered statistics and lies motivated by personal gain.
Using the "best case" global warming numbers agreed on by the summit to destroy one solution popular among the ignorant, he showed that for nuclear power to make enough of a difference to stop global warming by 2030, the world would have to replace the electrical output of one large coal-fired power station with an equivalent nuclear power station, EVERY DAY for the next 25 years. Every damn day. 365 per year. I would not have believed the figures if I hadn't seen every step of his working-out in that meeting.
Stopping global warming by 2030 is vital because it is a tipping-point where the rising temperatures begin to trigger the release of carbon dioxide and methane from natural sources, which raise temperatures, which release more carbon etc; in other words, after the expected temperature rise by 2030, we will experience a runaway greenhouse effect resulting in huge increases of eight degrees Celsius or more by 2100.
The effect of an eight degree rise in global temperatures would be catastrophic. One effect would be rising seas flooding the land upon which around half the world's population currently lives. Another would be the destruction of biodiversity on a scale dwarfing even our current extinction rate, as entire populations desperately flee to remote areas, rising seas drown whole ecosystems, and habitats disappear due to the climate shift.
In any case, it is clearly impossible for us to stop global warming solely by replacing our current and future power generation with nuclear power. Quite apart from the expense of building a new nuclear power station every day for 25 years, there is not enough nuclear fuel on the planet to cope with the demand. We must think of other ways, such as solar, wind, geothermal or tidal power, architectural albedo modification (Painting roofs and roads white, since white will reflect sunlight more effectively and increase Earth's reflectivity), geoengineering (from filling the stratosphere with silver foil to burying carbon dioxide in the ocean) and lifestyle changes.
However, if we're realistic, the governments of the world will never be up to the huge plethora of detail this multifaceted solution would entail. I personally think that Gregory Benford's plan, which he presented to the summit and showed us in the talk, is the best (cheapest, most practical and most effective) option we've currently got available. It is also the most fun, though an atmosphere full of floating silver foil might be a close second until planes start flying through air-drifts of foil and their engines explode.
Dr Benford, while doing most of the work himself, has exploited his friends at NASA to confirm that the engineering is viable, and the results were astounding: The whole project could be achieved with today's technology at a cost of $10 billion US dollars up-front, and another ten for maintenance over the decades of designed lifespan.
That's a lot of money, but it's still about two-fifths of the initial appropriation from Congress for the Iraq war. Benford proposes an international collaboration between wealthy nations to spread the load, and I would also suggest commercial sponsors. This would make the project almost indecently viable, considering the return each nation would get from being able to ignore Kyoto and its successors for as long as they feel like.
Gregory Benford's idea is to build a concave Fresnel Lens 1000 kilometres across but only a few millimetres thick at the L1 stable orbital point between us and the Sun, to slightly diffuse its light and cool us down enough to balance the warming effect of carbon dioxide, methane etc.
A few explanations are in order for that sentence:
- The L1 (Lagrange 1) point is a point in space on a direct line between the Earth and the sun, 1.5 million kilometres away from our little blue dot. At that point, the gravity of the Earth is balanced with that of the Sun in such a way that anything placed there will, if gently nudged back into place every 25 days or so, orbit the Sun once every year. This means that it will remain directly between Earth and Sun with almost no fuel expenditure. Currently there's a solar observatory satellite called SOHO there. It may have to move.
- A Fresnel lens is simply a magnifying (convex, outward curving) or diffusing (concave, inward curving) glass, with all the useless inside glass taken out and the lens concentrically cut into thousands of ringlike sections. If you've seen a lighthouse's light up close, or one of those flat sheets of plastic that nevertheless magnifies things, you've seen a convex Fresnel lens.
- Dr Benford's circular, millimetres-thin Lens would be made from an advanced plastic, and would need to be adjustable to fine-tune the amount of light that it prevented from reaching the Earth. Benford proposes spinning the 1000-kilometre structure fast enough to stiffen and maintain its shape. The Lens would need thrusters around its rim to keep from drifting away, and these may also assist the focussing and spinup stages.
The reduction in incoming sunlight would be 0.5 to 1%, enough to neatly stop global warming and keep temperatures stable. It would give us time to stabilise our emissions, then start the long process of filtering greenhouse gases back out of the atmosphere and storing them somewhere. The Lens can of course be adjusted, so as greenhouse gas levels dropped the diffusion effect would be reduced as well, until we reached a point where the Lens was no longer required and could be safely dismantled, or more playfully used to frighten the hell out of everyone in a medium-sized nation with an appropriate orbital insertion to enter the Earth's atmosphere flat-on.
The downside of this approach is that the other effects of the increased carbon dioxide would have to be addressed, such as increased plant growth (great if you like weeds) and less of an incentive not to pollute the air with fossil fuels. Coal might seem like an even better option to fast-growing developing countries like China, Brazil and Nigeria, meaning sooty, gritty misery for anyone living nearby, unless stringent pollution standards are internationally enforced somehow.
More info on the L1 point and Gregory Benford can be reached on Google, while the continuing progress of the 1-kilometre high, no-emission, oxygen-producing, 200-megawatt Australian solar tower which will be built by 2009 at Buronga, 25 ks east of Mildura in New South Wales, can be found here. The project has just recently purchased the land they plan to build upon, and has so far defied the usual predictions of failure that accompany any new way of doing things. Here's hoping that the Solar Tower is successful, just so some madman decides to build a 2-kilometre high one to show up those damn Aussies.