Global Warming and the Oceans
The world, and the ocean, is getting warmer. Average global temperatures are on the rise and increasing temperatures at the Earth's surface are accompanied by a significant rise in ocean temperatures to a depth of several hundred meters. Why is the Earth getting warmer? How will this affect the oceans? Many already know this story, but it is worth review.
Click to enlarge.
Click to Enlarge.
The Science
The burning of fossil fuels to drive cars, power factories, generate electricity and other "necessities" of modern life produces global warming pollutants. This creates "greenhouse gases", trapping heat in the atmosphere and in the oceans. The result of this, the greenhouse effect, has caused the Earth to heat up by about one degree Fahrenheit over the past century, with the most intense warming occurring over the last two decades. Click here to learn what the Joint Ocean Commission Initative says about the oceans and climate change.

What's at Stake
Our ocean covers about three-fourths of the Earth and by storing a thousand times more heat than the atmosphere does, it plays a key role in regulating the global climate. To learn more about what global warming is doing to the health of our oceans, read the section below: "The Potential Effects of Global Warming on our Oceans"
The Potential Effects of Global Warming on our Oceans
Sea Level Rise
Many experts warn that global warming will cause sea levels to rise dramatically. The rise in sea levels is due to two separate phenomena:
  • Thermal Expansion: Warmer water takes up more room than cooler water, which causes sea levels to rise.
  • Melting Ice: Glaciers and sea ice in both the Northern and Southern Hemispheres continue melting at rapid rates. As land-bound ice melts and flows into the ocean, sea levels rise.
    • Rising sea levels may completely submerge low-lying island nations and will certainly have devastating impacts on coastal populations worldwide. To learn more about the global effects of rising sea levels, click on the links below:
    National Geographic News: Warming to Cause Catastrophic Rise in Sea Level?
    National Geographic News: Greenland Ice Sheet Is Melting Faster, Study Says
    International Herald Tribune: Climate change to cause droughts, sea level rise in Australasia, research shows
    Los Angeles Times: Cities at Risk of Rising Sea Levels
    Scienceline: The Iceflow Cometh

    Disruption of the Global Ocean Conveyer Belt
    Oceanic Conveyor Belt of Heat
    A conceptual model of global ocean circulation.
    As glaciers and ice-sheets melt from rising global temperatures, they release fresh water which interferes with the formation of dense "bottom water". That "dense" water sinks to the ocean floor and helps drive the global ocean conveyor belt. The slowing (or halt) of the global ocean conveyor belt due to global warming would have disastrous effects on the way the ocean distributes heat around the world. To learn more about the effects of a disrupted global ocean conveyor belt, click on the links below:
    Bend Weekly: Study confirms mechanism for current shutdowns, European cooling
    CDNN: Ocean's heat transfer system at risk
    Time Magazine: Is Europe Due For a Big Chill?

    Chemical Changes - Ocean Acidification

    Bleached Coral on Australia's Great Barrier Reef
    The rise in CO2 levels causing global warming is also creating increasingly acidic oceans. As CO2 levels rise, higher levels of greenhouse gases are being pushed into the oceans. The changing chemistry of the oceans is having devastating impacts on ocean life and destroying the ocean food chain from the bottom up. To learn more, follow the links below:
    The Vancouver Sun: Warming oceans contain less oxygen for fish, conference told
    NewScientist.com: CO2 being pushed deep into oceans
    San Francisco Chronicle: Suffering oceans of abuse; We can't kill all sea life, but we're steadily poisoning it
    Alliance For The Chesapeake Bay, Bay Journal: Dead zones increasing in number, size throughout world's oceans, seas

    Ecosystem Disruption
    As the Earth grows warmer and the oceans collect more CO2, warming water and increasingly toxic seas will destroy vibrant ecosystems worldwide. For more information about how global warming will affect ocean ecosystems, click on the links below:
    Herald Tribune: Oceans' health linked to warming
    EurekaAlert: Global warming is reducing ocean life, increasing atmospheric carbon dioxide, say scientists
    The Washington Post: Growing Acidity of Oceans May Kill Corals
    The Orlando Sentinel: What happens if Virgin Islands' coral reefs disappear?
    The Los Angeles Times: A Chemical Imbalance
    Environmental News Network: Scientists Say Warming Triggers 'Dead Zone'

    Sources

    "Warming of the Southern Ocean Since the 1950s", Science Magazine, http://www.sciencemag.org/cgi/content/abstract/295/5558/1275, February 2002.

    "Climate Change 101: Understanding and Responding to Global Climate Change", Pew Center on Global Climate Change, http://www.pewclimate.org/global-warming-basics/climate_change_101/.

    Water Encyclopedia, Science and Issues: Ocean Basins, Section Mi-Oc. http://www.waterencyclopedia.com/Mi-Oc/Ocean-Basins.html

    "Ice sheet complexity leaves sea level rise uncertain", NewScientist.com news service, http://www.newscientist.com/article/dn11396-ice-sheet-complexity-leaves-sea-level-rise-uncertain.html, March 2007.

    United Nations Environment Program, Potential impacts of climate change, 30. Great ocean conveyor belt. http://www.grida.no/climate/vital/32.htm.