Climate Modeling - Beyond Smoke and Mirrors - page 43

Technical Note . : Geoengineering

The idea behind geoengineering is to introduce something
that has a cooling effect to balance the warming effect of the
accumulation of greenhouse gases in the atmosphere.

Table shows that sulfate aerosols have such an effect.

Three main schemes have been discussed. The

.

first is a giant
sunshade in space. To reduce the temperature by about F

C), it would have to be about ( miles across. This

would be very good for the aerospace industry.
A second idea is to seed the ocean with the minerals whose
lack limits the growth of plankton. There are parts of the
world s oceans that are low in the iron needed to support the

growth of these tiny creatures. The theory is that supplying
the iron will lead to a huge increase in plankton growth; the
plankton suck CO

'

out of the atmosphere to build their
structure as they grow, and transport the incorporated
carbon to the bottom of the ocean when they die, thereby
moving CO from the atmosphere to the ocean depths.

A third is to put more sulfate aerosols back into the
atmosphere where they will increase clouds and cut the
incoming radiation, the sulfur eventually falling out as sul-
furic acid and increasing the acid rain we have done so much
to cut back. Since these aerosols have only a short residence
time in the atmosphere, they have to be continuously added
if global warming is to be canceled, and will continually fall
out as acid rain.
New geoengineering schemes are being invented all the
time. The problem with all of these is unintended conse-
quences. There are thousands of people trying to understand
climate change including all the complex feedback effects
that make the problem so complex. There are even more
people trying to cut back on the emissions that cause it. The
geoengineering advocates are prepared to start action with-
out understanding what all the consequences will be. There
has already been one experiment at seeding the ocean with