Geoscience Reference
In-Depth Information
smoking. After a half century of education, even smokers admitted that
smoking was harmful.
12
In part to stem smoking, tobacco taxes are currently a major source
of revenues for governments. High carbon taxes have a more compel-
ling economic logic than do tobacco taxes—for the health of humans,
the planet, and government budgets.
The lesson for scientists is clear. There is no substitute for clear and
persistent explanations of the science along with refutations of contrar-
ian attacks. The evidence will become increasingly clear each year, as it
did with smoking. Obstructionists will fi nd themselves as if on a melt-
ing ice fl oe. The political winds will eventually shift.
A FINAL VERDICT
This chapter has presented a somber but realistic discussion of the
state of the debate and the obstacles to implementing effi cient and ef-
fective policies to slow global warming. Governments have made little
progress in implementing policies. Some of the obstacles are structural,
such as the global nature of the impacts and the long lag between costly
policies and ultimate benefi ts. Other obstacles are economic, as when
merchants of doubt attempt to confuse the public to maintain their
profi ts.
Now that we have reached the end, what would be the fi ndings of
an impartial jury? A fair verdict would fi nd that there is clear and con-
vincing evidence that the planet is warming; that unless strong steps
are taken, the earth will experience a warming greater than it has seen
for more than a half million years; that the consequences of the changes
will be costly for human societies and grave for many unmanaged earth
systems; and that the balance of risks indicates that immediate action
should be taken to slow and eventually halt emissions of CO
2
and other
greenhouse gases.
These basic fi ndings must be qualifi ed and constantly updated be-
cause of the uncertainties involved at all stages of the link from eco-
nomic growth through emissions and climate change to impacts and
policies. But the basic fi ndings have stood the test of time, rebuttal, and
