Ocean Action Hub

2 Mar 2017 - Scientists now understand how the carbon and methane emissions from our cars, livestock and electricity use are helping drive dramatic shifts in our climate through their contribution to the greenhouse effect. But they’re just beginning to untangle the effects of some of the other pollutants we produce. For instance, iron emissions from coal burning and steel smelting could actually be helping the oceans thrive and suck up more atmospheric carbon, according to new research.

If that sounds like a good thing, it isn’t. When we reduce our levels of iron oxide emissions—which we ultimately have to, to protect human and animals from inflammation and other adverse health effects—it will necessitate an even more drastic reduction in pollution to avoid the effects of climate change, the researchers warn.

Iron is a vital nutrient for nearly all living things. Humans need it to make new blood cells, while many plants need it to perform photosynthesis. However, iron is relatively rare in the open ocean, since it mainly comes in the form of soil particles blown from the land. For the trillions of phytoplankton in Earth's oceans, iron is a "limiting nutrient," meaning the available amount of it is a natural check on these creatures' population size. (To prove this, scientists in the early 1990s dumped iron across a 64 square kilometer region of the open ocean and quickly observed a doubling in the amount of phytoplankton biomass.)

Some scientists have proposed taking advantage of this fact through geoengineering, or deliberately intervening in the climate system using technology. Much like forests on land, phytoplankton in the ocean serve as "carbon sinks" because they take up carbon dioxide and then take that carbon with them into the deep ocean when they die. Therefore, adding more iron to the seas could potentially make these sinks even more potent at sucking up the carbon humans have dumped into the atmosphere, these proponents reason.

But the new research suggests that humans are already—albeit inadvertently—geoengineering this process, according to a study published today in the journal Science Advances.

Despite its promises to halt the growth of its carbon emissions by 2030, China remains the world's largest producer and burner of coal and the largest manufacturer of steel. Along with carbon, steel smelting and coal burning release particles of iron that can easily be carried away by the wind. Scientists have speculated for years that all those emissions could be fertilizing the oceans with extra iron, thus driving phytoplankton population growth, says Zongbo Shi, an environmental scientist at England's University of Birmingham. CONTINUE READING: http://www.smithsonianmag.com/science-nature/human-pollution-may-be-fertilizing-oceans-not-good-180962346/

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Publication date: 
02/03/2017
Publication Organisation: 
Smithsonian.com
Publication Author: 
Ben Panko
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