Phil
Tom, Ron, Bob and Gary,
Sometimes an idea grows on you. I know I'm no expert
in the areas I am going to address, so it's very likely any one of you will
explain quickly how wrong this is. Nevertheless, the idea has not gone
away, so I'm writing.
1. Some Assumptions
a. Global climate
change is real, and significantly caused by burning of fossil fuels. This
is the scientific assumption. There are zillions of details involved,
which I am glossing over. People can debate furiously which predictions
are most likely right.
b. Global climate
change will produce significant changes that will cause difficulty for
people. In other words, people would be better off if climate change
could be slowed or stopped.
c. Lots of opinion
leaders, both scientific and political, have called for action to stop or slow
climate change by burning less fossil fuels.
d. The current global
system of governance (several major, independent, mutually suspicious actors:
the US, China, the EU, Russia, Japan, India--along with lots of lesser, but
important nations) does not allow for coordinated political action necessary to
significantly reduce burning of fossil fuels.
2. A Conclusion
The policy changes called for by scientific and political
leaders will not be enacted in time to prevent very damaging climate
changes. The details that I glossed over in 1a become important
here. Maybe climate change won't be so severe. Maybe it won't be
damaging. So my conclusion should be restated: Probably the policy
changes advocated by the loudest voices, scientific and political, to combat
climate change will fail to prevent very damaging climate changes.
3. Comments on assumption 1d. The key factor here is
that China, and to a lesser extent India, will not cooperate with a carbon
emissions scheme that gets in the way of rapid economic expansion. The
global "haves" (the US and the EU) are beginning to slow or reduce
carbon emissions. But Russia has no motivation to slow oil & gas
production, since that is their main export. China argues, with some justice,
that the "haves" used fossil fuels to build their economies and it is
unfair to keep China from doing so as well.
It's possible that UN leadership will bring China and India
into line, that the "have" nations will pay to help China and India
develop without fossil fuel dependency. (How??) But I am
skeptical. I don't think the current political situation in the world
will succeed in meeting the challenge of global climate change. It's
unfortunate that world leaders must simultaneously face the challenge of Muslim
extremism; fighting terrorism naturally takes much of their attention.
4. Transition.
If the current
proposal won't work, we need some other way to attack the problem of global
climate change. It would be nice if a new proposal had the advantage of
not asking the Chinese to slow their economic growth so that the rich countries
can enjoy what they've already got. It would also be nice if the new
proposal didn't require huge changes in the global political system.
(Huge changes in the global political system will come someday, but I don't
think addressing climate change should hang on that.)
5. The proposal:
build a million umbrellas.
Look at the problem from a solar system perspective.
The earth is the target of the sun's radiation. The diameter of the earth
is roughly 8,000 miles. That means light from the sun strikes a target of
approximately 50,000,000 square miles (radius squared times pi). Solar
radiation is by far the greatest source of energy on the planet. Solar
radiation is either reflected back into space or absorbed by the atmosphere and
surface of the planet. As I understand it, global warming is caused by
changes in the chemical make-up of the atmosphere which causes a small increase
in the energy trapped into the planetary system. (Small, that is, when
compared with the enormous amount of energy striking the earth. This
"small" increase in trapped energy is enough to play havoc with the
climate.)
The current policy proposal is to stop polluting the
atmosphere with heat trapping emissions. What if we tried to block some
of the solar radiation?
Imagine a solar umbrella. It is carried into orbit by
an unmanned rocket, just like most of our satellites. Once in orbit, the
package unfolds an extremely thin material on an extremely light frame.
The umbrella has a diameter of a little more than a mile; its total surface
area is 1 square mile. The umbrella reflects solar radiation that would
have hit the earth back into space.
A million such umbrellas would represent 2% of the target
area of solar radiation hitting earth. Of course, if the umbrellas were
larger, we wouldn't need so many. If the umbrellas were more
sophisticated, they could be controlled from earth in some way to allow more
radiation at some times and less at others. The umbrellas would not need
to be in low earth orbit. There should be an internationally agreed
"umbrella zone" for the umbrellas to fly in. 1000-2000 miles
up? Half of the time, the umbrellas would be on the night side of the
planet, so we might need to double my numbers.
6. Comments.
a. China and India
could burn coal and publicize all their umbrella launches as compensatory
behavior. It would give the Chinese space program something useful to do.
b. In general, the
umbrella program gives the rich and powerful something to do as opposed to
changing something they are comfortable doing. Producing, installing, and
monitoring space umbrellas will be big business.
c. Air pollution is
still air pollution. Space umbrellas don't make air breathable. We
still would need governmental programs to discourage pollution.
d. Someone will
object: but now you're playing God with the climate! Answer: of course we
are, and we have been since we discovered that coal will burn. The
current policy proposal (somehow change fossil fuel usage worldwide) is merely
a different way of playing God with the climate.
e. If visible from earth, space umbrellas will change the
night sky forever. Poets should be consulted.
7. Questions I
thought of. I'm sure there are others.
a. Is it possible and
realistic to build space umbrellas? This is an engineering question,
Gary.
b. Am I too
pessimistic about international cooperation in regard to carbon
emissions? Tom and Ron, this is for you.
c. Would blocking 2% of solar radiation be enough to prevent
and/or slow climate change? Bob, we're looking at you.
The biggest question
is: what obvious errors am I making?
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