If I was given a few $trillion to solve atmospheric CO2/CH4, I would move mining to the moon, and move manufacturing and agriculture into orbit. Then smother the Earth-side economy with cheap/free stuff to discourage the remaining entrenched industry, and offer habitat space to anyone who prefers doing physical work for a living, over living in a highly regulated paradise on UBI + patreon.

For perspective, Gerard K. O'Neil gave a ballpark estimate of $31B (correction: $31B in 1972 dollars, $172B in 2013 dollars) for a v1 O'Neil cylinder made of steel. http://www.nss.org/settlement/physicstoday.htm