Environmental Engineering Reference
In-Depth Information
stronger evidence of this very unpleasant consequence of
ever-growing emissions.
AR
also mentions a wild card: the permafrost. In the
very high latitudes the ground has been frozen for most of
the past hundred thousand years. As the global tempera-
ture rises this material will begin to thaw, allowing what-
ever is trapped in and under it to escape. It is thought that
a great deal of greenhouse gas, particularly methane
(CH
), is there, and methane is a much stronger green-
house gas than CO
. If it escapes rapidly we will be in
trouble; if slowly, the trouble will be much less severe
because of methane
'
s short lifetime in the atmosphere (see
Table
.
).
.
Where Are We?
This is the end of the climate change part of this topic.
I have taken you through the science behind global
warming and the methodology used to predict what will
happen in various scenarios. There are uncertainties in
temperature change expected in each of the scenarios, but
the one that people should be concentrating on is the one
called business as usual or BAU (the IPCC AR
scenario
called RPC
scenario
run through all of the models predicts an average global
best-guess temperature rise of about
.
is closest to this). The RPC
.
F(
C) and a
C), with a rise about twice that
at the North Pole. The consequences will be disruptive at
the low end and destructive at the high end. If you live in
California there will be no snow in the winter, and the
water available in the summer will have to come from
large dams and reservoirs that have not been built yet. If
F(
range from
-
-
