Things are getting freaky on Spaceship Earth. Islands are disappearing, Arctic sea ice is melting faster (pictured) than the most pessimistic of predictions, and we may lose Greenland's ice sheet way ahead of schedule. The greenhouse effect is not just happening, it's accelerating, and it may start running away from us--if it hasn't already.

Given the increasing demand for energy around the world and the dearth of international action to reduce greenhouse gas emissions, we may be headed for a true global disaster. At that point we probably won't have time to wait around to see the benefits of cap-and-trade systems or research in photovoltaic technology, which raises the question: In case of a climate emergency, what can we do?

It might be time to roll out the big gun: climate control. As our climatic future looks increasingly dire, geoengineering--intentional, planet-scale alterations to the climate--has quickly gone from taboo to a matter of serious scientific consideration. While no one claims it will be a panacea for global warming, geoengineering may be the only way to buy some time and avoid a catastrophe. So far, many of the options look surprisingly cheap, rapid, and effective--at least on paper.

The core of the problem is simple. Greenhouse gases cause the atmosphere to heat up by decreasing the amount of energy that can escape to space. Geoengineering schemes use two ways to offset this process: They either remove the gases from the atmosphere, allowing more radiation to exit, or deflect a portion of the sun's light--about 1.8 percent should do the trick--reducing the amount of radiation absorbed by the earth. Simple, right? Well, it's a big planet with some very complicated climatic and ecological systems, and there's no guarantee that any approach will actually work in real life. Here's our take on some high-profile emergency-response proposals.