Toxic Redux: Global Warming Releases Imprisoned Poisons
Oct 31, 2011 10:50AM
During the industrial boom of the last half of the 20th century, thousands of manmade chemicals were created. Used in consumer products, pest control and crop production, they have also proved deadly, causing and contributing to cancers, birth defects and other health crises.
Once the connection was scientifically proven, the international community restricted or banned the use of 12 pollutants, including DDT and polychlorinated biphenyls (PCB), at the 2001 Stockholm Convention on POPs, or persistent organic pollutants (Tinyurl.com/3sa2v47). This group of the world’s most toxic compounds takes decades to degrade, gradually accumulating in the fatty tissues of humans and wildlife.
Initially, climatic forces helped to limit the reach and impact of the chemicals in places like the Arctic, where POPs trapped in snow, soil and oceans were capped by sea ice, and atmospheric levels of the toxic substances monitored by Canada and Norway have steadily declined during the past decade.
Scientists at the Canadian environmental agency, Environment Canada, think that global warming is reversing the downward trend. They found that as the planet warms, sea ice and snow continue to melt and the pollutants, called legacy POPs, are being released back into the atmosphere with potential worldwide effects.
Once airborne, POPs can ride wind and ocean currents to as far as Latin America and Africa. It also undermines international treaties regarding human exposure to high-risk toxins.