SLOWING CLIMATE CHANGE BY REDUCING EMISSIONS: MITIGATION - The Climate Casino - page 166

Scientists are working on other technologies that could speed up
natural CO 2 -storing processes. A “synthetic tree” that would remove CO 2
from the atmosphere has been proposed by Columbia University's K laus
Lackner. 13 Some scientists have proposed methods for using the oceans
to absorb excessive carbon.
All of these ideas face two major obstacles. They are likely to be
expensive, and the required scale of removal is vast. These points can
be illustrated with an example that is defi nitely feasible today. The Ca-
nadian province of British Columbia has vast tracts of forest that are
largely untouched. Suppose that British Columbia were to devote half
of its forest land, or about 300,000 square kilometers, to carbon removal.
This would involve growing trees, cutting them after they mature, and
storing them in a way that prevents leakage of the CO 2 into the atmo-
sphere. British Columbia would soon have a huge mountain of trees,
but devoting half the province to the project would offset less than 0.5
percent of the world's CO 2 emissions in coming years.
Perhaps a large number of carbon-eating trees, BC-type tree projects,
and Lackner-style synthetic trees could tilt the CO 2 trajectory downward,
but it is a gigantic undertaking. Such efforts are more likely to supplement
rather than substitute for emissions reductions, unless some completely
different and more effi cient carbon-removal process is discovered.
Most of the options for sharp reductions in CO 2 emissions look
costly, as calculations in Chapter 15 will show. Are we unduly pessi-
mistic because today's technologies were developed in a world that was
unconcerned about climate change? Is it possible that, with the appro-
priate incentives and by devoting suffi cient scientifi c talent to the task,
global warming might be solved by a revolution in energy technologies
that simply makes the problem disappear?
Look back for a moment at Figure 3. This fi gure shows that the car-
bon intensity of the U.S. economy has declined around 2 percent per year
over the last eight decades, with only small variations on that trend. Is it
possible that a major revolution in energy technologies might increase
the rate of decarbonization to 10 or 20 percent per year and thereby
bend down the emissions trajectory sharply? I consider how such a sce-