Short of mining the moon to make orbital mirrors out of lunar tin foil, foucus on rapid and complete decarbonisation while accepting that there were consequences to largely ignoreing the problem for the last sixty years.

Solution is a maybe an overstatement, but

• destroy the methane. That's energetically favorable, so it can be done more easily. Makes some CO2 but it's 50x less bad that way.
• get the carbon back out and stick it into the ground. We'll be on our way when the Mauna Loa CO2 curve bends and goes down for a year or two. That's energetically expensive, but we'll figure out a way (hopefully) to do it wherever we have solar overproduction.

Trees are nice, but it's nowhere near enough to do that.