According to a Friday piece on Motherboard, a group of scientists gathered at a geoengineering conference. Two rather radical ideas were proposed to deal with global warming, a theory advanced that human caused CO2 emissions are causing the Earth’s temperatures to rise. The ideas are based on the use of space based lasers, similar to those that were once proposed by President Ronald Reagan as part of his SDI program to provide a shield against Soviet nuclear missile attack.
One idea is to use a space based laser to create clouds in the Earth’s atmosphere. The notion that lasers can create water droplets that in turn can form clouds has been tested in the laboratory. The formation of more clouds would help to reflex sunlight away from the Earth’s surface and thus cool the planet.
The other idea is to use lasers directly to blast greenhouse gases floating in the Earth’s atmosphere, thus eliminating them directly. This would constitute a brute force method of eliminating greenhouse gasses once they are emitted. One problem is that they might not be in sufficient concentrations to be dealt with effectively in this fashion.
The use of space based lasers proved to be controversial when they were first proposed as part of a missile defense system. Opponents argued in the 1980s that they were technically infeasible and politically dubious, the latter thanks to the ABM Treaty. The matter became moot after the fall of the Soviet Union and the end of the threat of global thermonuclear war. The rise of rogue nuclear states such as North Korea and possibly Iran, along with chilling relations with China and Russia, may lead to a revival of space based missile defense.
The notion of using lasers as a countermeasure against climate change will likely run into problems of expense as well as uncertainty about the unintended consequences of zapping the atmosphere from space. But if the United States decided to deploy laser weapons in space, say to defend against missile attack from Iran or China, they might be used at least on a test basis to see what they can do against greenhouse gasses. That is something Reagan has not imagined when he first proposed the notion over 30 years ago,