Engineering the Climate

This week the media got a sneak preview of the most recent 5-year study from the Intergovernmental Panel on Climate Change -- a United Nations group of more than 500 scientists from around the globe. The report, which will officially be released this Friday, concludes that "humans have already caused so much damage to the atmosphere that the effects of global warming will last for more than 1,000 years." The good news is: we haven't reached the tipping point yet -- there's still time to reverse the damage we've done and avoid the most severe consequences of climate change.

But some scientists have already started to think about the worst case scenario. What if we don't have the political will to break our addiction to fossil fuels and overconsumption before it's too late? In this case, we might want to consider more drastic measures -- like devising a technological fix, as a last ditch effort to save ourselves.

One such idea, soon to be published in the Journal of the British Interplanetary Society, is to shade the Earth slightly for several decades by creating huge dust clouds in semi-stable orbits near the Moon. The dust could be obtained by deflecting a nearby comet to this region of space and then grinding it up -- but this has the disadvantage of possibly causing the comet to strike the Earth itself and destroy all life as we know it. The other potential source of dust is the Moon. There's plenty of dust there, but we would need to launch it into orbit. This is somewhat easier on the Moon, since the gravity is weaker and there is no atmospheric drag, but it is still a formidable challenge.

To obtain the necessary amount of lunar dust, the author estimates that we would need to launch "about 300 metric tons/s for 10 years" and that "the energy can be derived directly from the Sun". The amount of energy required is about 2% of the current global demand for energy, hundreds of times more solar power capacity than we currently have on Earth -- and we need it on the Moon! If we cannot manufacture solar panels on the Moon, then we would need to launch them from the Earth -- and this would cost about 300 times the current U.S. national debt. This is much more expensive than simply blanketing the Earth with solar panels now -- a technological fix to the climate problem before it gets out of hand.

The Earth from Space

In a live conversation from the International Space Station last night, Indian-American astronaut Sunita Williams told a group of school children in India that "Space is an amazing place for all. Here there are no borders, and the world is very peaceful". Sunita traveled to the ISS aboard the space shuttle Discovery, and plans to work there for the next six months.

The view of a world without borders may be the greatest benefit of making space tourism more accessible to the people of Earth in the future. But with a current price tag of about $20 million, few people can afford the trip. Several entrepreneurs are developing concepts for bringing space travel to the masses, and they are already busy building "spaceports" in places like New Mexico and west Texas. Competition between these companies will help push the price down by a factor of 100, but there are still relatively few people who will be able to afford a $200,000 seat.

Fortunately, an ongoing project by NASA is bringing the view of our planet without borders (or even clouds!) to computer screens around the globe. No doubt you have already seen the impressive composite image of the Earth, pieced together from satellite data obtained at different times and places when there were no clouds to block the view. NASA's "Blue Marble" project is now generating such images every month, so we can watch the surface of the Earth changing over time. At the highest resolution, each pixel in these new images spans just 500 meters on the ground.

Maybe if more people see these images and begin to think of the Earth as a place without borders, we can all live in the peaceful world that Sunita was talking about.