Geoscience Reference
In-Depth Information
fore, governments must step in and regulate or tax activities with
signifi cant harmful externalities. Global warming is no different from
other externalities; it requires affi rmative governmental actions to re-
duce harmful spillovers.
Global externalities pose special diffi culties because there is no
workable market or governmental mechanism to deal with them.
There is no world government that can require everyone around the
globe to participate in the solution. The absence of a world government
makes it diffi cult to stop the overfi shing of whales, rein in dangerous
nuclear technologies, and slow global warming.
The fact that climate change is both external to markets and global
is the central hurdle that policymakers must overcome if they are to
slow the pace and avoid the dangers of climate change in the coming
years.
WHY ARE CARBON DIOXIDE EMISSIONS RISING?
Discussions of global warming usually begin with the emissions and
accumulation of CO
2
and other greenhouse gases (GHGs) in the atmo-
sphere. However, the real starting point is with humans and their daily
lives. I will use my own experience as an American living in a midsized
city, but one could equally well talk about a Nigerian oil worker, a Ger-
man brewer, or an Indonesian weaver.
Suppose I am invited to give a talk at the University of Connecticut,
about 50 miles from my home in New Haven. The most convenient way
to get there is to drive my car up and back. The round trip is about 100
miles, and taking into account sitting in traffi c and city driving, my car
will get about 20 miles per gallon, so I consume 5 gallons of gasoline.
This will produce about 100 pounds of CO
2
, which will come out of the
tailpipe and go into the atmosphere. I can't see it or hear it or smell it,
and I generally do not even think about it. If I am like most people, I
will probably assume that my trip will have no effect on the world's
climate, and so I will ignore the consequences.
But there are more than 7 billion people around the world making
analogous decisions many times every day and every year. Suppose that
