Climate Change Could Alter Ocean Food Chains, Leading to Far Fewer Fish in the Sea - by Jefferson Keith Moore

Climate change is rapidly warming the Earth and altering ecosystems on land and at sea that produce our food.  In the oceans, most added heat from climate warming is still near the surface and will take centuries to work down into deeper waters.  But as this happens, it will change ocean circulation patterns and make ocean food chains less productive.

In a recent study, I worked with colleagues from five universities and laboratories to examine how climate warming out to the year 2300 could affect marine ecosystems and global fisheries.  We wanted to know how sustained warming would change the supply of key nutrients that support tiny plankton, which in turn are food for fish.

We found that warming on this scale would alter key factors that drive marine ecosystems, including winds, water temperatures, sea ice cover and ocean circulation.  The resulting disruptions would transfer nutrients from surface waters down into the deep ocean, leaving less at the surface to support plankton growth.

As marine ecosystems become increasingly nutrient-starved over time, we estimate global fish catch could be reduced 20 percent by 2300, and by nearly 60 percent across the North Atlantic.  This would be an enormous reduction in a key food source for millions of people. 

Climate Change Could Alter Ocean Food Chains, Leading to Far Fewer Fish in the Sea