Time's Up - Stolen Future, Broken Present: The Human Significance of Climate Change - page 43

irreversible for 1,000 years after emissions stop.” If we did manage to stop
emiting carbon dioxide, “radiative forcing”—or what we usually call the
greenhouse effect—would indeed decline, but that decline would be
“largely compensated by slower loss of heat to the ocean.” 80
This finding means that even if we manage to cut our output of carbon
dioxide, Earth's temperatures will go up and stay up . But wait a minute: as
I mentioned above, the rise in temperature lags behind the rise in carbon
dioxide concentrations by many years, so that even ater we stop emiting
carbon dioxide, the temperature would rise another 0.6° Centigrade or
so—a time lag that all the above estimates take into account. So the real-
ity is that even after we cut our greenhouse gas output, the temperature
level would continue to rise —and then eventually level off and stay at that
higher level.
Unfortunately, then, the physics of the climate will not let us reverse
the effects of our misbehavior now. If we push temperatures up, they
are going to stay there. We have no second chance. And the first one is
already slipping away.
It would be nice to pause here and suggest that it is not yet absolutely
certain that those vicious circles are under way in full force and for good.
That hesitation might have been plausible a year or two ago. But by now,
the dire state of the Arctic feedback loop and our sense of its conse-
quences for the entire global climate leave us litle room for doubt.
Is there no basis for hope left to us? One last consideration remains,
one final bedrock for hope: our general humility in the face of the vast
complexity of Earth's dynamic systems. Only the sense that our knowl-
edge is limited, that something may be taking place and might still appear
of which we have litle inkling, stands between us and a frank acknowl-
edgment that all is lost.
Many others seem to have come to a similar conclusion. Some of
them show their awareness of our situation by introducing an entirely
new angle on the problem, suggesting forms of geoengineering to address
our plight; the Arctic Methane Emergency Group I mentioned in the
introduction is a good case in point. But almost invariably such sugges-
tions threaten to harm the planet in their own way. One idea is to inject
aerosols into the atmosphere to dim the sun and lower the temperature.
But doing so would ultimately cause serious ground-level pollution and