Terraform Earth Now!

I've been reading the Mars trilogy by Kim Stanley Robinson.  It's quite good, though rather long and has some tedious (for me) passages detailing Martian landscape and geology.  Terraforming (and the political battles surrounding the speed, methods, and outcomes) is a major theme of the series.

One thing I've been noodling on is the idea "Terraforming" earth.  I see global warming as a proof-of-concept that we can influence (control) our macro-environment.  According to this article, we've have been doing it indirectly for 1000's of years:

"About 7,000 years ago, levels of carbon dioxide and methane began rising. During every previous similar interglacial period, of which there are at least seven, greenhouse-gas levels fell.

To explain this, palaeoclimatologist Bill Ruddiman formulated the “early anthropogenic hypothesis,” which holds that the source of these gases was land clearing and flooding for rice production by prehistoric farmers beginning 8,000 years ago. While this hypothesis still ruffles the feathers of many a climatologist, there remains no better evidence explaining the Holocene greenhouse-gas anomaly.It is even possible that global warming caused by prehistoric farmers has delayed the onset of the next ice age, which is due right about now."

from "http://www.wired.com/wiredscience/2009/05/ftf-ellis-1/"