Channel 8 had an interesting show yesterday about something I never heard of. It’s called radiation dimming and apparently it’s another side effect of us on the earth’s climate. It refers to air pollution which keeps radiation from the sun from entering the atmosphere and so keeps the earth cooler at daytime and warmer at nights. It is believed to partially mask the effect of the greenhouse gases on global warming.
So how is this dimming a bad thing? Well, while trying to undo the trouble, we maintain our focus mainly on reducing air pollution by cutting back on CFC, putting filters on just about everything and creating more resource efficient machinery. That’s all nice and dandy, but the damage has already been done and this fixes only one of these two side effects. Nature is all about balance and in this case we’ve broken the balance with air pollution, but created our own delicate balance instead. Now, while reducing air pollution, we broke the balance again. The ozone layer is still damaged, but our own “synthetic ozone layer of pollution” is slowly diminishing. Hence, while trying to fix the errors of the past for the long term, we’re actually making things worse for the short term. The greenhouse gases effect is getting stronger because its masking is slowly reduced.
The researcher the show was talking about had a nice method of proving his point. Contrails also take part of radiation dimming and the skies are filled with them. After 9/11, all flights in the USA were grounded for a couple of days. This gave him an excellent chance to test his theory and see if there’s any temperature difference when removing this polluter. And lo and behold, a difference of over 1 °C in the daily temperature variation was observed.
More information is available from BBC, Wikipedia (using the above links) and channel 8′s reruns.