Re: How to Cool a Planet (far fetched ideas)

ianparker2@xxxxxxxxx wrote:

The only way you can reverse global warming, other than by cutting down
greenhouse gases is a system of mirrors partially blocking out the
Sun.. In fact the green route will not be that effective.


Mirrors are a terribly inefficient way to do this.

You can get by with *far* less mass if the orbital element
just scatters the light through a small angle. A diffractive
element at the earth-sun L1 point would need to scatter the
light by ~ .01 radians. This would require roughly 100x
less mass than a reflective element. Moreover, it would
have close to 100% duty cycle, unlike LEO mirrors, and it
could be designed to scatter non-visible IR, so it would
not alter the night sky.

All these albedo modification schemes fail to solve the
ocean acidification problem, though, and they cause
the stratosphere (which is cooled by increasing CO2)
to get even colder. At some point the CO2 has to be
kept out of the atmosphere. Burning all the seafloor
methane, for example, is going to put an enormous amount
of carbon into the air, more than even from burning
all the coal.

Paul
.