It's no secret that global warming, or, more accurately, climate change, is a threat to the future of Earth and all who live here. Nonprofits, governments, think tanks, scientists and individual, concerned citizens have been advocating solutions for years, with new, renewable energy sources being the most common and potentially effective.
But as time runs out to make the incremental changes necessary to avert ecological disaster (see How Global Warming Works), some drastic measures have appeared on the table. One of these last-ditch plans to avoid complete climate disaster is what can basically be described as a sunhat. For Earth.
A chemical sunhat, to be more specific. In lessons learned from volcanic eruptions, we know that when mass amounts of sulfur are ejected into the atmosphere, the Earth is cooled, because sulfur reflects sunlight. The big idea is to induce that sulfur "sunshade" artificially by sending tons of sulfur particles into the stratosphere, perhaps using planes, balloons or rocket launchers.
Grand as it is, this scheme is one of the cheapest and simplest of the ideas on table, which also include space-based mirrors, artificial trees and dissolving mountains [source: Kunzig].
They're Hail Marys, no doubt. And if CO2 levels don't come down soon, we just might find ourselves building a planetary sunshade to save the world.
For more information on averting disaster, including measures being taken in Japan, look over the links on the next page.