Freeman Dyson's excellent review of William Nordhaus' excellent A Question of Balance: Weighing the Options on Global Warming Policies in the New York Review of Books is a must-read. Here's the nut of Nordhaus' analysis:
The main conclusion of the Nordhaus analysis is that the ambitious proposals, “Stern” and “Gore,” are disastrously expensive, the “low-cost backstop” is enormously advantageous if it can be achieved, and the other policies including business-as-usual and Kyoto are only moderately worse than the optimal policy. The practical consequence for global-warming policy is that we should pursue the following objectives in order of priority. (1) Avoid the ambitious proposals. (2) Develop the science and technology for a low-cost backstop. (3) Negotiate an international treaty coming as close as possible to the optimal policy, in case the low-cost backstop fails. (4) Avoid an international treaty making the Kyoto Protocol policy permanent. These objectives are valid for economic reasons, independent of the scientific details of global warming.
This “low-cost backstop” sounds promising. Is it? Dyson thinks so:
At this point I return to the Keeling graph, which demonstrates the strong coupling between atmosphere and plants. The wiggles in the graph show us that every carbon dioxide molecule in the atmosphere is incorporated in a plant within a time of the order of twelve years. Therefore, if we can control what the plants do with the carbon, the fate of the carbon in the atmosphere is in our hands. That is what Nordhaus meant when he mentioned “genetically engineered carbon-eating trees” as a low-cost backstop to global warming. The science and technology of genetic engineering are not yet ripe for large-scale use. We do not understand the language of the genome well enough to read and write it fluently. But the science is advancing rapidly, and the technology of reading and writing genomes is advancing even more rapidly. I consider it likely that we shall have “genetically engineered carbon-eating trees” within twenty years, and almost certainly within fifty years.
Carbon-eating trees could convert most of the carbon that they absorb from the atmosphere into some chemically stable form and bury it underground. Or they could convert the carbon into liquid fuels and other useful chemicals. Biotechnology is enormously powerful, capable of burying or transforming any molecule of carbon dioxide that comes into its grasp. Keeling's wiggles prove that a big fraction of the carbon dioxide in the atmosphere comes within the grasp of biotechnology every decade. If one quarter of the world's forests were replanted with carbon-eating varieties of the same species, the forests would be preserved as ecological resources and as habitats for wildlife, and the carbon dioxide in the atmosphere would be reduced by half in about fifty years.
How about bounties for carbon-eating tree technology?