And also by increasingly poor urban planning! Let's not forget that covering ever-greater parts of most cities in concrete does nothing to let the earth do the natural thing - soak in rainwater - and everything to cause floods. And the same goes for the countryside: industrial farming has done away with hedging and trees and is responsible for the hardpan under almost all fields, preventing rainfall from ever making its way through to its natural destination: aquifers.
RE: The Global Warming Hoax