Now, it is a bit difficult to explain the effect but suffice to say that the pollution particulates block some of the energy of the sun from reaching the ground, therefore less heat. Apparently during the 3 days after the 9/11 attack when all commercial aircraft were grounded, on scientist discovered that just by removing the pollution from the contrails of the aircraft (which is only one small portion of global pollution on a daily basis), the average temperatures throughout the US rose on average by 1°C for the period. It doesn’t sound like much, but neither does the 0.6°C rise in average global temps we have experienced so far, and that small change is causing the northern ice cap to reduce every year, and melt glaciers all over the world!
So as we reduce particulate pollution, like via catalytic converters on cars, and enforce stronger pollution controls from diesel fuels, we must at the same time reduce the green house gas emissions or we face a rapid escalation in global warming.
I don’t think I have articulated it very well, so I found this series of videos on YouTube that make up one documentary made by the BBC titled ‘Global Dimming’ which explains all the science, how the effect was discovered and what would happen if we tackle one issue without tackling the other at the same time. I hope you take the time to watch it. It certainly opened my eyes to another issue that I wasn’t aware off and that will effect us all soon enough.
Global Dimming Documentary Part 1/5
bbc Climate change- global dimming part 2
Climate Change — Global Dimming part 3
Global Dimming Documentary Part 4/5
Global Dimming Documentary Part 5/5