A new report/analysis of three methods of  climate-engineering is available online from Copenhagen Consensus Center.

Climate engineering could offer an extremely cheap, fast solution to climate change, according to this comprehensive analysis of its costs and benefits.

An Analysis of Climate Engineering as a Response to Climate Change by Dr. Eric J Bickel and Lee Lane shows that we might be able to cancel out this century’s global warming by spending no more than $9 billion, and that climate engineering might be able to achieve as much for the planet as carbon cuts at a fraction of the cost.

Three methods of solar radiation management are explored in this research. Solar radiation management involves bouncing sunlight back into space, to avoid warming.

The authors look at stratospheric aerosol insertion (launching material like sulfur dioxide or soot into the stratosphere to mimic the effects of volcanoes, which create a hazy layer scattering and absorbing sunlight); marine cloud whitening (spraying seawater droplets into marine clouds to make them reflect more sunlight); and the deployment of a space-based sunshade (launching many tiny transparent screens into space that would focus a small amount of the sun’s light away from Earth).

Air capture focuses on capturing carbon dioxide from the atmosphere and securing it in land or sea-based sinks. This technology, according to Dr. Bickel and Lane, is not as promising as solar radiation management from a technical or cost perspective. Dr. Bickel and Lane find that the cost of stratospheric aerosol insertion would be in the magnitude of $230 billion, with benefits fifteen-times higher.

Marine cloud whitening with a fleet of unmanned ships would be extremely cheap: for about $9 billion, all of the global warming for the century could be avoided, with benefits adding up to about $20 trillion.

Dr. Bickel and Lane conclude: “the results of this initial benefit-cost analysis place the burden of proof squarely on the shoulders of those who would prevent such research.”

I don’t know what to think about this idea.  I guess I am open to considering and exploring it.  But the skeptic in me wonders if this will actually work-could people really control something as complex as the earth’s climate without screwing it up even more?   And the purist in me wishes we could just not mess it all up in the first place.  John Tierney shares my skepticism.  And since Bjørn Lomborg seems to be supportive of the approach (and is also director of the institute that sponsored the report) I have to wonder… But his short letter about the report (you can read or download it here) seems to make sense.  Am I missing something?

John Tierney has a nice story about climate engineering in general and the report here.

Read the full report here and blogs about the report here and here.

From the Lomborg letter:

Global warming will mean that more people die from the heat. There will be a rise in sea levels, more malaria, starvation, and poverty. Concern has been great, but humanity has done very little that will actually prevent these outcomes. Carbon emissions have kept increasing, despite repeated promises of cuts.

We all have a stake in ensuring that climate change is stopped. We turned to climate scientists to inform us about the problem of global warming. Now we need to turn to climate economists to enlighten us about the benefits, costs, and possible outcomes from different responses to this challenge.

World leaders are meeting in Copenhagen this December to forge a new pact to tackle global warming. Should they continue with plans to make carbon-cutting promises that are unlikely to be fulfilled? Should they instead delay reductions for 20 years? What could be achieved by planting more trees, cutting methane, or reducing black soot emissions? Is it sensible to focus on a technological solution to warming? Or should we just adapt to a warmer world?

Much of the current policy debate remains focused on cutting carbon, but there are many ways to go about repairing the global climate. Our choices will result in different outcomes and different costs.

The optimal combination of solutions will create the biggest impact for the least money. A groundbreaking paper by economists Eric Bickel and Lee Lane is one of the first – and certainly the most comprehensive – study of the costs and benefits of climate engineering. Deliberately manipulating the earth’s climate seems like something from science fiction. But as President Barack Obama’s science adviser, John Holdren, has said it has “got to be looked at,” and many prominent scientists agree.

Bickel and Lane offer compelling evidence that a tiny investment in climate engineering might be able to reduce as much of global warming’s effects as trillions of dollars spent on carbon emission reductions.

Climate engineering has the advantage of speed. There is a significant delay between carbon cuts and any temperature drop – even halving global emissions by mid-century would barely be measurable by the end of the century. Making green energy cheap and prevalent will also take a long time. Consider that electrification of the global economy is still incomplete after more than a century of effort.

Many methods of atmospheric engineering have been proposed. Solar radiation management appears to be one of the most hopeful. Atmospheric greenhouse gases allow sunlight to pass through but absorb heat and radiate some down to the earth’s surface. All else being equal, higher concentrations will warm the planet.