Use of solar shades is a proposed approach to the mitigation of global warming. By intentionally changing the Earth's reflectivity scientists propose that we could reflect more heat back out into space. But every coin has a reverse side.
Recent studies showed that injecting sulfur compounds into the atmosphere – one of the main ways to cool off the planet – can destroy the Arctic ozone layer and hinder recovery of the Antarctic ozone hole by about 70 years.
On the other hand, it is not so bad as it painted. Another study suggests that recovery of the ozone hole over Antarctica will modify climate in the Southern Hemisphere and even worsen Antarctic warming. While the world faces rising temperatures, there has been cooling in the interior of Antarctica in summer, which is ascribed to the depletion of ozone overhead.
A computer model of interactions revealed that a return to pre-1969 ozone levels would mean atmospheric circulation patterns now shielding the Antarctic interior from warmer air to the north will begin to break down during the summer.
As early as 1974, Russian expert Mikhail Budyko suggested that if global warming became a problem, we could cool down the planet by burning sulfur in the stratosphere, which would create a haze.
The cooling effect that volcanic eruptions often have on the climate due to ash particles in the upper atmosphere can be seen as an analogy of how these methods might work.
A preliminary study by Edward Teller and others in 2002 presented the pros and cons of various relatively "low-tech" proposals to mitigate global warming through scattering/reflecting sunlight away from the Earth via insertion of various materials in the upper stratosphere, low earth orbit, and L1 locations.
This study is an attempt to resolve the problem of greenhouse gases and their accelerating emission. Due to warning reports that all the efforts to reduce emission are now ineffective scientists have to work out something new to protect the planet.