This weeks Horizon covered a subject which I'm sure I've seen an article in Scientific American, but I didn't realse was having such a big effect. Basically global dimming is caused by the particles that we emit as waste products from burning of fossil fuels. This tiny particles reduce the amount of sun light reaching the planets surface both by screening out the light them selves and by causing more reflective clouds to form around them. So far this doesn't sound to bad, we are sure that we are now rasing the planets temperature with C02 emissions which is causing global warming, so surely this dimming is a good thing, counter acting the effects of the warming.
However as with many things, it's not that simple. The dimming has helped hide the effects of the warming, so that our predictions and computer models could be way out and under estimating the effects. Also a more serious problem is that now we are starting to address many of the causes of the dimming by cleaning up car and power station emissions with really addressing the CO2 emissions, we are could be being hit by the warming now. The program used the summer of 2003 as an example of this and then when on to predict if we continue as we are, reducing particle emissions with out doing the same for CO2, we could end up with a world in 100 years time that as large areas basically uninhabitable by humans.
Scary stuff. But what really made me think is that for all of the money, time and expertise put in to the climate change problem, we have only recently noticed this effect. What other effects have we not considered in all of our climate models? The world is turning out to be lots very complex systems linked in complex ways and we are beginning to throw lots of these complex and linked systems out of balance. What problems are we storing up for our selves and future generations?