Roof over an African country with solar panels to provide alternative source of power.
Tow the North Pole ice mass south to irrigate the deserts.
Seed oceans with iron to stimulate growth of carbon-guzzling plankton
Cover deserts with plastic to reflect sun's rays back into space
Turn cut-down or fallen trees and plants into charcoal and bury them rather than burning them or letting them rot.
Deploy sailing ships to spray sea-water onto clouds making them denser to keep earth cooler.
Launch space-based deflectors of sun's rays
Put sulphur into atmosphere to make clouds denser and keep sunlight out.
Put pumps in ocean to mix hot and cold water and prevent hurricanes.
Deploy machines which suck carbon from the atmosphere.