Frank Ackerman and coauthors: The Economics of 350

A new report (pdf) by Frank Ackerman and coauthors explores the economics of 350. It's published by the E3 Network, in partnership with Ecotrust and the Stockholm Environment Institute.

Stopping global warming and protecting the earth’s climate is a daunting challenge. To prevent a climate crisis we have to move quickly to transform the ways in which we create and use energy, develop petroleum-free transportation, and much more. These changes will not be free; there is already resistance to paying for the first steps along this road. ...

[James] Hansen and numerous co-authors reach two key conclusions: first, the global average temperature may be much more sensitive to greenhouse gases in the atmosphere than is commonly believed; second, to avoid dangerous climate change, we may need to reduce the concentration of CO2 in the atmosphere from today’s 385 ppm to 350 ppm CO2 by 2100, if not sooner. ...

How might it be possible to achieve negative emissions, that is, to remove carbon dioxide from the atmosphere? At present there are three widely discussed methods of carbon removal, of which the first two are currently available and the third is still under development.

First, reforestation (and the prevention of deforestation) is a key component of the path that achieves 350 ppm CO2 by 2100. New international agreements, institutional structures, and financing arrangements would be needed to achieve the reduction in atmospheric CO2 concentration. Hansen is not alone in highlighting the importance of reforestation; assuming success in creating the needed institutions, this is not the most expensive part of a 350 ppm scenario.

Second is “biochar”: it is possible to convert plant material into charcoal, and then bury it in the soil; that process sequesters carbon, and may have beneficial effects on soil productivity and water retention. Biochar offers an interesting but perhaps limited option for carbon capture.

Third, biomass could be burned with carbon capture and storage (CCS), a much-discussed possibility that needs further development. Biomass — including sugar cane, switchgrass, corn (maize), palm oil, and carbon-rich waste products from the paper and agricultural industries — can be burned in power plants to generate electricity and heat. ...

At least four European research groups have modeled global scenarios that lead to 350 ppm CO2; one finds that in a world with unemployed labor and other resources, the stimulus from new climate investments might accelerate economic growth. The other three groups find net annual costs that are generally between 1 percent and 3 percent of world output; their work highlights the importance of assumptions about the development of new technologies, which will be crucial over a time span of one or more centuries. ... Is a potential cost of 1 to 3 percent of world GDP a large or a small number? The answer depends on how seriously you take the risks of climate change. ...

[T]he best available estimates imply that we can, indeed, afford the economics of 350. What we cannot afford is too little climate policy, too late.