Study: Global warming worsening watery dead zones

A new study says global warming is likely playing a bigger role than previously thought in dead zones in waterways around the world and it's only going to get worse.
Dead zones occur in oceans, lakes and rivers when fertilizer runoff clogs waterways with nutrients, such as nitrogen and phosphorous. That leads to an explosion of microbes that consumes oxygen and leaves the water depleted of oxygen, harming marine life.
Smithsonian Institution researchers found about two dozen different ways that climate change worsens the oxygen depletion in a study today in the journal Global Change Biology.
The researchers looked at 476 dead zones worldwide. They used computer models to forecast that those dead zones will increase by about 4 degrees from the 1980s to the end of this century.