[ExI] Subsidy for Burning Coal

[Keith Henson]

2061 May 4

(Found on a new disk that must have fallen through a time warp.)

Subsidy for Burning Coal?

It is amusing to consider how the press for CO2 in the atmosphere has
seesawed back and forth in the past 60 years.

In the teens, CO2 was the devil incarnate, causing the ice caps to
melt and trapping heat to warm the world to an intolerable level.

The rapid switch from fossil fuels to space based solar power that
occurred between 2025 and 2035 ended the build up. Near the end of
that time, construction switched away from older structural materials.
Concrete and steel gave way to grown diamond and nanotubes. At first,
there was no concern since the CO2 level was much higher than the pre
industrial level. Withdrawing CO2 from the atmosphere started at a
modest level. It doubled again and again. Both surface and underground
construction raided the built up atmospheric CO2 for material. By
2056, the CO2 was back to pre industrial levels. If it were not for
the oceans giving up vast amounts they had absorbed in previous
decades, the fall would have been even faster.

Crop yields would have been seriously hurt, except food production had
moved underground. That was in the aftermath of weather disruptions
from three closely space volcanic eruptions. (Tunnel farms, of course,
used vast amounts of carbon to build the arches.) There it was
possible to concentrate the CO2 remaining in the atmosphere. The crops
grew under artificial lights. Letting the surface go back to
grasslands and forests was another big sink for CO2.

Now the CO2 has declined to the point we face an incipient ice age.
The mountain glaciers have grown at several hundred meters per year
for the last several years. The snow fields in the north are staying
on the ground year round. The surface of the Arctic Ocean is again
solid pack ice.

Humanity remaining on the planet has two choices. (Assuming we don't
want another ice age.) We can build reflectors in space to increase
the solar irradiation, or we can put more CO2 into the atmosphere.

Our grandfathers knew how to mine coal and burn it on a grand scale.
How much subsidy must we offer to do it again?