almost impossible not to think that all is lost, that even if we act, it will be
too late. 78
These realities undermine the premise of a major activist enterprise
of our moment—Bill McKibben's drive to encourage many public insti-
tutions to disinvest in fossil-fuel companies and thus help prevent the
United States from pushing the biosphere beyond the limits of its toler-
ance. In the Rolling Stone article in which he lays out his case, McKibben
first explains that the 2° threshold on which international negotiators
rely is too high, but then invokes on a specific “carbon budget” derived
from that threshold to argue we have time to make a difference through
the strategy of divestment. 79 His effort, praiseworthy as it is, relies on a
contradiction between his knowledge that we've already virtually met the
limit of what the Earth can tolerate and his description of what a certain
kind of activism can still accomplish.
Given all these factors, we can no longer assume that our efforts
will bear fruit, that the civilizations of the Holocene will survive in any-
thing like their present form. An honest look at the task ahead and the
time remaining should disabuse us of our unspoken confidence that the
world we know will endure in something of its current form for the rest
of our lives.
But hold on , someone might say, what if we lower our emissions ater
that target date? Wouldn't the Earth's temperatures eventually decline as well,
geting back down to a level that would not cause extensive climate change?
Even if we've been very slow and don't meet the target of 450 ppm, isn't there
hope that we can eventually hit that or a lower target, and all will be well?
In this question, I hear the voice of the last optimists speaking—the
voice of those who hope that, however stupid and cowardly we all are,
however slow to act, however likely to botch the entire task for a few
more years, we might still have a chance. The activists at 350.org, acting
on something of this premise, are organizing efforts to reduce our carbon
dioxide emissions to that lower number in the long term, hinting that if
we can do so, we will avert the onset of serious climate change.
But it simply isn't so. he eighth reason we have so litle time is that
once we warm the planet up to a certain point, it will not cool down again
for a very long time. A recent paper showed that “the climate change that
takes place due to increases in carbon dioxide concentration is largely