Global dimming is the reduction in the amount of sun energy hitting the surface of the Earth. Research shows that the amount of sun energy reaching the surface of the earth has fallen 9% in Antarctica, 10% in the USA, 16% in the UK, 22% in Israel and 30% in Russia since the 1950s. Water evaporates correspondingly more slowly. The results are from long term studies and data, and two relatively rapid studies, the change in temperature differences during the day when planes were all grounded in the USA after 9/11 in 2001 and a study comparing sun energy received in the north and south of the Maldives.
It seem that the particles in the air allow smaller water particles to be suspended on them as clouds, and these reflect more heat and light back out into space, hence shielding the earth. This affects evaporation of ocean water and may have caused the droughts and famines in North Africa.
There has been a real effort to lessen air pollution particularly in Europe which may have helped African monsoonal rainfall, but if the dimming lessens and more sunlight comes into the atmosphere, it will mean that the greenhouse effect will worsen.
Revised calculations show that global warming may be 10 degrees Celsius in a century, because the melting of the Greenland ice sheet and the release of oceanic methane, which is 14x worse than carbon dioxide as a greenhouse gas will make the global warming phenomenon irreversible.
The answer is that we have to stop burning fossil fuels. We need electric cars, renewable energy, and to replace planes with trains as much as possible. It a shame we have a Liberal Government!
This 49 minute video is from the BBC Horizon program.