“Relatively low cost” plan would cool the Earth’s poles by 2 °C:

To state the obvious, no scientist wants to fill the air with
sulfur, drench the last remaining polar bears and penguins in acid rain,
or give carbon emitters any excuses not to clean up their act. But
faced with our current trajectory, on which summer sea ice in the Arctic
will more or less disappear by 2050 or earlier, humanity finds itself
between a rock and a hard place. All options need to be on the table,
evaluated, and to some extent ready to go early enough to make a
difference.

So research into SAI is progressing quickly, and
concentrating it at the poles – an approach referred to as subpolar
deployment – may deliver better returns for significantly less money and
acid rain than a global model. Prior research has indicated that spring
and early summer is likely the most effective season to do it, and that
only doing this at one pole could have asymmetrical effects on global
weather, so it’s probably prudent to target both, with a fleet of planes
that travels with the seasons.

“Relatively low cost” plan would cool the Earth’s poles by 2 °C: To state the obvious, no scientist wants to fill the air with
sulfur, drench the last remaining polar bears and penguins in acid rain,
or give carbon emitters any excuses not to clean up their act. But
faced with our current trajectory, on which summer sea ice in the Arctic
will more or less disappear by 2050 or earlier, humanity finds itself
between a rock and a hard place. All options need to be on the table,
evaluated, and to some extent ready to go early enough to make a
difference. So research into SAI is progressing quickly, and
concentrating it at the poles – an approach referred to as subpolar
deployment – may deliver better returns for significantly less money and
acid rain than a global model. Prior research has indicated that spring
and early summer is likely the most effective season to do it, and that
only doing this at one pole could have asymmetrical effects on global
weather, so it’s probably prudent to target both, with a fleet of planes
that travels with the seasons.Read More