This is part
two of a series of blog posts on reversing global warming. In the first I
proposed trying iron dust on the oceans to cause phytoplankton blooms that
would eliminate atmospheric CO2, which would (in theory) reduce global warming.
The second method would be to cut down on heating from the Sun.
It is obvious
that reducing the amount of solar radiation reaching the Earth would lower the
temperature of the Earth. My suggestion is not new. Others have suggested
shielding the Earth from the Sun, and some have made detailed plans. Basically
the shield need not be fancy, and it could be made largely of space junk and
rocks. There are some amazingly expensive proposals that have been made. The
first proposal linked below would cost only about 350 Trillion dollars;
apparently the one who dreamed it up just wanted to be on record as having made
such a proposal. The second one isn’t as expensive, and some of the ideas are
quite reasonable.
The second
proposal might be affordable, and it probably would work quite nicely. It
proposes putting a dust cloud around the Earth by turning some asteroids in
dust and persuading the dust to flow in the right pattern. Moving the asteroid
into a suitable orbit before turning it to dust would work nicely. The proposal
would start with a near Earth asteroid, and crush much of that. Then a mass
driver would be used to spread the dust. And the remains of the asteroid would
become another satellite that would hold the dust in place as the moons of
Saturn help to keep the rings in place.
The third
proposal has some good and some bad features. It wouldn’t cost all that much.
The website doesn’t include a cost estimate, but it would be similar to the
cost of a Mars ship. One of the bad points is that a rather large asteroid
would be put into a fairly close Earth orbit. A small mistake in placement
could result in a large mass dropping to Earth. That might cut down on solar
radiation by putting up large clouds of dust from Earth. It might also kill
many people, etc.
I think that
the easiest way to block sunlight would be something like a window blind in geosynchronous orbit. The blind need not be
solid, and it would certainly have to be flexible. It could be made from space
junk and material from near Earth asteroids. The exact material would depend on
what was available out there, but one side would have to ne reflective. If it
weren’t reflective, then it would become rather hot, because there would be
nothing to conduct the heat away, so it would have to radiate away, and that
might not be reliable. It might also be possible to convert the heat to
electricity. There already are many things in geosynchronous
orbit, so we would have to put this at a different distance, but it could house
communications and other facilities; it would even be possible to put a few
hotels along the blind to help to defray the cats of construction, and the NSA
would love to have it as a listening post.
The concept is
simple, but estimating the cost will have to wait until we decide on the placement
and size of the shield. The location will be important, because there are so
many things in orbit already, and we would have to avoid interfering with
those. When the shield will be completed, it can replace many satellites, but
until then it will have to be out of the way. Another consideration is the
latitude at which it would orbit, or if it would have a sinusoidal orbit.
Having it at high latitudes would block sunlight to a larger area, and that
might be desirable, but the reduction in temperature would be more noticeable
at lower latitudes. Its effects would be more lasting in the higher latitudes
also, because the icepack and glaciers would hold the cold for a long time.
That location of it would also make it more like correcting the axial tilt of
the Earth. A shield just a thousand miles wide could put the entire Polar
Regions into permanent darkness and cold. The only downside would be that the
scientific station at the South Pole would become less useful. But all of
Antarctica would become dark, so it would be less useful for all purposes.
We will have
to make a decision. There is something to be said for all of the shields, but I
will present other alternatives in part three.
Comments and
suggestions are solicited.
First
sunshield proposal
Second
Third
No comments:
Post a Comment