Remember the ozone hole? Perhaps my reader is too young. Back in the 70s, the ozone which protects the Earth from dangerous solar UV radiation began developing a hole, caused, it was eventually discovered, by CFCs. Through both private and public efforts, the Montreal Protocol was promulgated to reduce the use of CFCs, and now that hole is shrinking; I briefly discussed this with one of the climate scientists involved and reported it here.
Now Spaceweather.com is reporting a new threat to the ozone:
An international team of researchers led by David Oram of the University of East Anglia has found an unexpected, growing danger to the ozone layer from substances not regulated by the treaty.
The danger comes from a class of chemicals known as “chlorocarbons.” Dichloromethane is an example. It is used in paint stripping, agricultural fumigation, and the production of pharmaceuticals. Over the past decade dichloromethane became approximately 60% more abundant. “This was a major surprise to the scientific community and we were keen to discover the cause of this sudden increase,” says Oram.
Developing economies in East Asia appear to be the source. “Our estimates suggest that China may be responsible for around 50-60% of current global emissions [of dichloromethane], with other Asian countries, including India, likely to be significant emitters as well,” says Oram.
More information on Spaceweather.com, including nuggets on the strange weather patterns in the Far East which may be responsible for moving these chemicals, formerly considered too short-lived to be harmful, into the upper atmosphere.
In a way, it’s a lesson in how there is always something new to learn in science.
