Down to the wire : confronting climate collapse / David - Index of

governance S 19
headlines of the future will likely include the use of fossil fuels
and land abuses decades before. We are already committed to a
substantial warming of the Earth, by as much as 1.8°C above preindustrial
levels (Lynas, 2007, p. 246).
Many credible scientists believe that we still have time to avert
the worst, but not a minute to waste. No one knows for certain
what a “safe” threshold of heat-trapping gases in the atmosphere
might be. For hundreds of thousands and perhaps millions
of years, the level of carbon dioxide did not go above ~280 parts
per million (ppm), compared to the present level of 387 ppm,
with another ~2+ ppm added each year. Climate scientist James
Hansen has recently proposed 350 ppm CO as the upper bound-
2
ary of safety (Hansen et al., 2008).
We are clearly in uncharted territory. Further delay in stabilizing
and reducing levels of CO poses what economist Nicho-
2
las Stern calls a “procrastination penalty” that will grow steadily
until we eventually cross a point of no return. In other words,
it will be far cheaper to act now than at some later date when
effective action may no longer be possible. If the warming should
occur abruptly “like the ones that are so abundant in the paleoclimate
record,” we will have no time to adapt before catastrophe
strikes. 8 And there is good reason to believe that the climate system
is indeed highly sensitive to small changes: “Earth’s climate is
extremely sensitive: it is capable of taking inputs that seem small to
us and transforming them into outputs that seem large” (Broecker
and Kunzig, 2008, p. 181).
No matter what our personal preferences, politics, or beliefs
may be, as greenhouse gases accumulate in the atmosphere, temperatures
will continue to rise until the Earth reaches a new equilibrium.
Even were we to stop emission of CO today, sea levels
2
from the thermal expansion of water and increasing mass from the
melting glaciers and ice caps would change coast lines for perhaps
the next thousand years (Solomon et al., 2009; Archer, 2009). If the
rate of melting is rapid or sudden, the migration inland will create