Say what you will about the looming catastrophe facing the world as the pace of global heating and polar melting accelerates. There is a silver lining.

Look at a map of the US.

The area that will by completely inundated by the rising ocean-and not in a century but in the lifetime of my two cats-are the American southeast, including the most populated area of Texas, almost all of Florida, most of Louisiana, and half of Alabama and Mississippi, as well as goodly portions of eastern Georgia, South Carolina and North Carolina. While the northeast will also see some coastal flooding, its geography is such that that aside from a few projecting sandbars like Long Island and Cape Cod, the land rises fairly quickly to well above sea level. Sure, Boston, New York and Philadelphia will be threatened, but these are geographically confined areas that could lend themselves to protection by Dutch-style dikes. The West Coast too tends to rise rapidly to well above sea level in most places. Only down in Southern California towards the San Diego area is the ground closer to sea level.

So what we see is that huge swaths of conservative America are set to face a biblical deluge in a few more presidential cycles.

Then there's the matter of the Midwest, which climate experts say is likely to face a permanent condition of unprecedented drought, making the place largely unlivable, and certainly unfarmable. The agribusinesses and conservative farmers that have been growing corn and wheat may be able to stretch out this doomsday scenario by deep well drilling, but west of the Mississippi, the vast Ogallala Aquifer that has allowed for such irrigation is already being tapped out. It will not be replaced.

So again, we will see the decline and depopulation of the nation's vast midsection-noted for its consistent conservatism. Only in the northernmost area, around the Great Lakes (which will be not so great anymore), and along the Canadian border, will there still be enough rain for farming and continued large population concentrations, but those regions, like Minnesota, Wisconsin and Illinois, are also more liberal in their politics.

Finally, in the Southwest, already parched and stiflingly hot, the rise in energy costs and the soaring temperatures will put an end to right-wing retirement communities like Phoenix, Tucson and Palm Springs. Already the Salton Sea is fading away and putting Palm Springs on notice that the good times are coming to an end. Another right-wing haven soon to be gone.

So the future political map of America is likely to look as different as the much shrunken geographical map, with much of the so-called "red" state region either gone or depopulated.

There is a poetic justice to this of course. It is conservatives who are giving us the candidates who steadfastly refuse to have the nation take steps that could slow the pace of climate change, so it is appropriate that they should bear the brunt of its impact.

The important thing is that we, on the higher ground both actually and figuratively, need to remember that, when they begin their historic migration from their doomed regions, we not give them the keys to the city. They certainly should be offered assistance in their time of need, but we need to keep a firm grip on our political systems, making sure that these guilty throngs who allowed the world to go to hell are gerrymandered into political impotence in their new homes.

There will be much work to be done to help the earth and its residents-human and non-human-survive this man-made catastrophe, and we can't have these future refugee troglodytes, should their personal disasters still fail to make them recognize reality, mucking things up again.

It should be considered acceptable, in this stifling new world, to say, "Shut up. We told you this would happen."

Dave Lindorff is an investigative journalist and columnist. His latest book, co-authored by Barbara Olshansky, is "The Case for Impeachment" (St. Martin's Press, 2006 and now available in paperback, suitable for a last-minute Christmas gift). His work is available at www.thiscantbehappening.net