Geoscience Reference
In-Depth Information
400
390
380
370
360
350
340
330
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1960
1970
1980
1990
2000
2010
Figure 6.
Atmospheric concentrations of CO
2
measured at Mauna Loa Observatory,
Hawaii, 1958-2012.
around the world. Based on intensive measurements and modeling,
scientists believe that most of the nonatmospheric CO
2
eventually goes
into the oceans, where it spreads gradually into the depths. But that is a
very slow process.
You can do an experiment yourself to picture slow ocean diffusion.
Fill a clear glass with water. Then put a few drops of red food coloring
at the top. Time how long it takes for a perceptible amount to get to the
bottom of the glass, and also how long it takes for it to appear uniformly
diffused. Now pretend that the glass is 6,000 feet deep. This will give
you an idea of how long it takes CO
2
to be absorbed into the deep
ocean.
The major result of these scientifi c fi ndings is that CO
2
released into
the atmosphere stays there for a long time. This has very important im-
plications for how we think about climate change. The long residence
time means that the effects of today's actions cast a long shadow into the
future. They do not just wash away in a few days or months. In this sense,
CO
2
and other GHGs are more akin to nuclear wastes than to normal
pollution. This long residence time will come back to haunt us when we
consider the problem of discounting costs and benefi ts.
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