With Speed and Violence Fred Pearce - Global Commons Institute

the air will flatten out. Reaching the safety-first target of 935 billion tons of
carbon dioxide would require an immediate and dramatic ditching of
business as usual in the energy industry worldwide. Global emissions would
need to peak within five years or so, to fall by at least 50 percent within the
next half century, and to carry on down after that. A trillion-ton target could
be achieved with more modest early cuts and greater reductions later.
Another consideration is the danger posed by the sheer speed of warming.
Many climate scientists say that rapid warming may be more destabilizing to
vulnerable systems like carbon stores and ice caps than slower warming. For
this reason, it could be important to take some urgent steps to limit
short-term warming while we get carbon dioxide emissions under control.
And there is a way to do that—through a concerted assault on emissions of
gases other than carbon dioxide that have a big short-term "hit" on climate.
Let me explain. Different greenhouse gases have different lifetimes in the
atmosphere, ranging from thousands of years to less than a decade. For
convenience, climate scientists usually assess their warming impact as if it
operated over a century—carbon dioxide's average lifetime in the
atmosphere. But this is rather arbitrary. And it has the effect of "tuning" the
calculations to make carbon dioxide seem more important, and other gases
less so. Most significant here is methane, which, however you measure it, is
the second most important man-made greenhouse gas after carbon dioxide.
Measured over a century, the warming caused by a molecule of methane is
about twenty times as great as that caused by a molecule of carbon dioxide.
But methane does most of its warming in the first decade, its typical lifetime
in the atmosphere. It has a quick hit. Measured over the first decade after its