Out of the entire Project Earth series, this idea seems to be the most expensive and hardest to accomplish. Currently, I do not know how they plan to engineer the space sunshield it self or how they expect it to get into space but the sunshield seems unfeasible before seeing their ideas.All knowledge of costs and time to implement aside, the Space Sunshield idea is to setup a network of mirrors in space to reflect some of the Sun's light from shining on Earth warming it further. If they can get their plan in motion, they expect that these mirrors will be able to reflect the sun rays and slow down global warming.
This idea is very similar to the Brighter World episode. The main similarity is reflecting the Sun's light away from Earth. The difference is sending mirrors up into space.
You can catch Project Earth, Space Sunshield on the Discovery Channel on September 12th at 9PM EST.
Updates from the episode:
Apparently, I was thinking too much on spending money on space agencies on launching these lenses, I wasn't thinking of smaller private individuals who use small rockets.
If only 2 percent of the sun's rays are redirected, this would be able to bring global temperatures back down to preindustrial eras.
The original lens was two inches thick and about one foot in diameter. The engineer's idea calls for 16 trillion lenses to be launched. Aside from the costs of labor and production, the cost to launch these lenses would cost one million trillion dollars to launch. Enough to bankrupt the world for a very long time.
The Discovery Project Earth team was able to scale the lenses down to make them 1 micron thick instead of his current two inch think lenses. They were successful in shrinking the lenses on a sheet of silicon.
In order to get the sun refracting lenses into space, the team first tried to use a coil gun. They proved that the coil gun can work but they hope that using traditional, proven rocket technology will be able to control variables better than a system that launches at over 1,000 g force.
Rocket technology on the other hand only causes about 25g. The only problem with using rockets for a launch is that the force of 25g's are in all directions because of the rumbling of the rockets.
Unfortunately for the team, the rocket crashed. Everything was destroyed, they were not even able to retrieve pictures or film from inside the rocket monitoring the lenses. The entire experiment was a large failure. The Project Earth team can now only speculate "IF" their experiments worked.
Based on vague, hypothetical ideas, they came to the conclusion that the sunshield would be able to actually reverse global warming but only if our carbon dioxide levels are reduced.
