Dosing Iron in the Ocean Could Slow Global Warming
Fertilizing the ocean with iron could help reduce atmospheric carbon dioxide levels by promoting diatom blooms that suck CO2 out of the air. Then, when these microscopic creatures die, they would sink to the bottom of the ocean and take the carbon with them.
In a report published this week, researchers induced carbon to fall 34 times as fast as natural rates for nearly two weeks - the highest such rate ever observed outside the laboratory. The results offer fresh hope to would-be geoengineers hoping to draw down ever-increasing concentrations of industrial CO2 in the atmosphere.
Experiments like this have been carried out in the past with unquantifiable results, but the researchers decided to use a large scale ocean eddy to help contain the iron and better be able to observe the effects. They chose the eddy known as Antarctic Circumpolar Current as the location. Based on previous research of this area of ocean, it was determined that less than 10 percent of the eddy's waters mixed with the surrounding ocean.
This location was ideally suited since hunger for iron rules the microscopic sea life of the Southern Ocean surrounding ice-covered Antarctica. Cut off from most continental dirt and dust, the plankton, diatoms and other life that make up the broad bottom of the food chain there can't get enough iron to grow.
There are some downsides to these findings. Such fallen carbon only resides in the deep for a few centuries at best. Eventually, it makes its way back to the surface as the ocean's bottom water circulates and rises anew near the equator (although carbon buried in sediment might stay buried longer). And such techniques might be capable, at best, of sequestering one billion metric tons of carbon dioxide per year (based on the extent of iron-deficient waters around the globe), compared with annual human emissions of more than eight billion metric tons and rising.
Dosing Iron in the Ocean Could Slow Global Warming
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