New NOAA report shows how climate change is fueling 5,000-square-mile ‘dead zone’ in Gulf of Mexico

Global warming doesn’t just mean scorching temperatures and rising sea levels. It also means the death of oceans, lakes, rivers and other bodies of water. Dead zones — areas in the water with little oxygen — are proliferating worldwide due to a double whammy of higher temperatures and increasing pollution, killing marine life and turning once-living habitats into hypoxic deserts.

Scientists have monitored one such dead zone in the Gulf of Mexico – thought to be the largest in US waters – for over three decades. On June 2, the National Oceanic and Atmospheric Administration announced that the dead zone in the Gulf of Mexico is expected to reach 5,364 square miles (or about eight times the size of the city of Houston) this year. That forecast is only slightly below the five-year average of 5,380 square miles and about 15 percent below last year’s measurement. But it’s nowhere near the state goal of 1,900 square miles set in 2001.

Dead zones primarily form when runoff containing chemicals such as nitrogen and phosphorus from agricultural practices, industrial activities, and population growth leak into nearby water bodies and encourage algae to grow like crazy. Overgrown algae sink and decompose, and the decomposition process deprives the water of its oxygen and robs marine life.

Climate change only makes the situation worse, as water contains less oxygen as it warms, making it easier for dead zones to form. In addition, sea creatures need more oxygen in warmer weather because they use more energy.

The Gulf of Mexico dead zone is fueled by nutrient runoff from farms along the Mississippi River. The Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force used NOAA’s hypoxia forecasts — based on computer models from five universities and one government agency — and nutrient monitoring from the US Geological Survey to set targets for nutrient reductions in Mississippi watersheds.

To confirm the predictions and the size of the dead zone, NOAA supports a surveillance survey each summer to include all major coastal weather conditions that could affect the size and oxygen levels of a dead zone, such as hurricanes and tropical storms.

“The Gulf dead zone remains the largest hypoxic zone in United States waters, and we want to gain insight into its causes and effects,” said Nicole LeBoeuf, deputy administrator for NOAA’s National Ocean Service, in a press release issued by the agency . “The modeling we are performing here is an important part of NOAA’s goal to protect, restore, and manage the use of coastal and marine resources through ecosystem-based management.”