Environmental Engineering Reference
In-Depth Information
reduction in emissions required to stabilize at
ppm
can obviously be achieved more easily than those for
ppm. A target of
ppm also gives more time to bring
the developing nations into the program as needs to
happen if any of the stabilization scenarios is to achieve
its goal
(more about how this might be done in
Chapter
).
In any world program the industrialized nations will
have to take the lead and reduce emissions faster than the
developing world. Think of the richer countries running
below the trajectory corresponding to the chosen goal,
while the poorer counties run above it for a while. There
are many more people in the poor countries today
than in the rich ones, and as the poor ones improve their
standard of living they will have to fully participate in
whatever is agreed as the world goal. As noted earlier,
China and the United States are the world
'
s largest
emitters (China
s emissions today are now larger than
those of the United States). However, China
'
s per capita
GDP (PPP) is about one-sixth of that of the United
States. The policy problem is not only determining the
goal, but how the reductions in emissions are shared
among nations.
The shapes of these trajectories are also an issue. For
any of the goals it is possible to let emissions go up for
longer than shown and then bring them down more
rapidly later, or bring them down earlier than the peak
shown and more slowly later. The sooner we start the less
chance that increasing temperature will cause serious
damage to the world
'
s ecosystem. However, the sooner
we start the more the burden falls on today
'
s economies
and people. The economists have been arguing over how
'
