Jan. 26, 2009 -- The future of Earth's oceans is beginning to look a lot like a mass extinction, according to new research. Today, approximately 2 percent of the seas qualify as 'dead zones' -- naturally desolate, oxygen-starved regions where higher life forms either can't breathe or find enough food to subsist. But according to a computer simulation out to 100,000 years in the future, those zones could engulf one-fifth of the seas within a few millennia if humans don't change their carbon-emitting ways soon. Gary Shaffer of the University of Copenhagen in Denmark led the study published yesterday in the journal Nature Geoscience, which examined the oceans' long term reaction to several emissions and warming scenarios. In the worst case, business-as-usual scenario, society keeps burning fossils fuels unabated until 2100. Carbon dioxide levels in the atmosphere quadruple, and the planet warms by as much as 5 degrees Centigrade (9 degrees Fahrenheit). Related Content: Get the Latest in Science and Tech News From Discovery How Stuff Works: Should We Be Worried About the Dead Zone in the Gulf of Mexico? America's Meat Habit Feeds Gulf Dead Zone Assuming humanity stops with its emissions after that, air temperatures should reach their maximum around the year 2200, and then start a slow decline. But the oceans will just be getting warmed up -- literally. It will take another 2000 years or so before ocean circulation fully mixes warm surface waters down into the depths. Water loses its ability to dissolve oxygen as it warms, so hotter oceans mean larger dead zones. And some research has suggested that ocean circulation will slow down as the oceans heat up, too, causing an effect that Shaffer estimates could deplete oxygen content by up to 54 percent worldwide by around the year 5000. Of course, there is a lot of uncertainty in just how dire the consequences will be. For instance, it's possible that the carbon we emit may have less of an effect on the oceans than his model predicts. "This is proposing some interesting hypotheses, that if true, would be a big deal," Anand Gnanadesikan of the National Oceanic and Atmospheric Association's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey said. "But that's all they are right now -- hypotheses." And humans could undertake to cut emissions, which would improve the outlook. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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