Noted physicist and science fiction author Gregory Benford talked about potential policies to achieve climate stabilization. His proposals ranged fro the sensible to the sensational, and he concluded with an enthusiastic call for human control of the climate, so it was n interesting talk.

According to Benford, the most important approach at the current time is not the development of non-fossil fuel sources (they can’t provide enough energy) or reductions in energy demand (because of economic demands), but carbon sequestration. In other words, neither state power nor piety will reduce greenhouse gas emissions. Kyoto’s emission limits won’t be complied with, and it’s only a drop in the bucket. (Alcohol prohibition didn’t work; energy prohibition won’t either.)

On the positive side, energy intensity and carbon intensity are dropping, at least in the industrialized world. But this will not be enough. By 2050 we will need 10-30 terrawatts of carbon-free power. To do this, Benford argued, there need to be massive, government incentives for massive technological development, on the scale of the Manhattan Project. Technologies in the current research and development pipeline are not enough to stabilize carbon dioxide levels in the atmosphere. Thus, energy intensity improvements will help, but they will not be enough. Nor will non-fossil fuel energy sources close the gap on their own. The land requirements for solar are massive, and biomass has limitations as well.

Benford proffered three immediate policy steps – emergency sequestration of carbon, changing the reflectivity of buildings and blacktop in cities, and increase the amount of cloud cover over the tropical oceans. Carbon sequestration into the ocean could eliminate the carbon dioxide equivalent of 10 terrawatts per year. Coal is going to get used eventually, so sequestration is particularly necessary. Forests can sequester carbon too, but this will not be as effective as ocean sequestration. Salt domes are another possible sequestration site, but they are too likely to leak (due to holes punched by wildcatters). One problem with ocean sequestration, however, is that it would alter the PH-balance of the ocean, with potentially catastrophic impacts on coral (a problem that Benford says is occurring anyway, and that humans could learn to address as well).

Other ideas are a bit far-fetched (such as a $500 billion solar power satellite with a lens the size of North America to reduce the amount of solar radiative forcing on the Earth. This is theoretically possible, but it ain’t gonna happen.

Rapid climate change is still a potential problem for which we need to be prepared, Benford suggested. If rapid climate change were to occur – such as would shut down the ocean circulation current – he argued that we will need some way to enhance the Earth’s albedo effect with aerosol particles so as to reduce the radiative forcing on the planet. This may seem an extreme scenario, but Benford argued that something of this sort should be examined. Indeed, he proposed to try this out above the Arctic to see if it is a viable climate control strategy (for a cost of approximately $100 million). It’s an interesting idea, but I don’t see it as particularly politically viable (even ignoring some of the potential unintended consequences of such an experiment).

Benford’s bottom line was that human beings are altering the climate whether we like it or not. The choice is whether to keep doing it “stupidly” as we are now, or “smartly” in a way that serves human interests. What humanity must do, he argued, is become the “stewards of the Earth,” and take deliberate control of the planet’s climate. He may be right, but don’t expect to hear that in a political campaign any time soon.