As our use of fossil fuels continues to exacerbate global climate change, we’re starting to see the quantifiable effects of our rapidly warming planet. One of the most obvious effects is the rapid decline in arctic sea ice, one of the earth’s largest carbon sinks and a catalyst of life for beings all over the planet.
This melting ice spells disaster for polar bears and other animals that depend on it for food and shelter. But as a NASA-led study recently discovered, homeless polar bears and invasive crabs aren’t the only horrifying consequences of the sea ice decline.
Drastic reductions in Arctic sea ice over the last decade may be intensifying the chemical release of bromine into the atmosphere, resulting in ground-level ozone depletion and the deposit of toxic mercury in the Arctic, according to a new study.
The study found that as temperatures warm, melting sea ice triggers an interaction between sunlight, salt in the water, and a chemical element called Bromine. When these mix, the salty ice releases bromine into the air and starts a cascade of chemical reactions called a “bromine explosion.” These reactions rapidly create more molecules of bromine monoxide in the atmosphere. Bromine then reacts with a gaseous form of mercury, turning it into an ozone-eating pollutant that falls to Earth’s surface.
In the spring of 2008, satellites detected increased concentrations of bromine, which were associated with a decrease of gaseous mercury and ozone. The international team of researchers, led by Son Nghiem of NASA’s Jet Propulsion Laboratory, used the topography of mountain ranges in Alaska and Canada as a “ruler” to measure the altitude at which the explosions took place. After the researchers verified the satellite observations with field measurements, they used an atmospheric model to study how the wind transported the bromine plumes across the Arctic.
The model, together with satellite observations, showed the Alaskan Brooks Range and the Canadian Richardson and Mackenzie mountains stopped bromine from moving into Alaska’s interior. Since most of these mountains are lower than 6,560 feet (2,000 meters), the researchers determined the bromine explosion was confined to the lower troposphere.
“If the bromine explosion had been in the stratosphere, 5 miles [8 kilometers] or higher above the ground, the mountains would not have been able to stop it and the bromine would have been transported inland,” Nghiem said.
Say what you will about polar bears or potential oil spills, but shouldn’t the thought of clouds of toxic bromine seeping toward our cities be enough to give us pause when making the choice between fossil fuels and renewable energy? Apparently not.
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