COOLING THE EARTH
People have proposed methods to cool the earth, so we would not
have to reduce CO2 too much. A study
by Lenton+Vaughan compares cooling proposals. All have huge side effects. Some
give partial help. They make the following four points:
"By
2050, only stratospheric aerosol injections or sunshades in space
have the potential to cool the climate back toward its pre-industrial state...
"[L]arge
reductions in CO2 emissions,
combined with global-scale air capture and storage, afforestation,
and bio-char production, i.e. enhanced CO2 sinks, might be able to bring
CO2 back to its
pre-industrial level by 2100,
"[S]tabilising
CO2 at 500 ppm,
combined with [more reflective]...
clouds, grasslands, croplands and human settlements might achieve a patchy
cancellation....
"Ocean
fertilisation options are only worthwhile if sustained on a millennial
timescale... Enhancing ocean upwelling or downwelling have trivial
effects on any meaningful timescale."
Of
all the options, bio-char,
reflective
roofs, and reduced soot
seem to have the least harmful side effects (data
on roofs).
Go to the Study
of cooling options