Tuesday, March 6, 2012

The Other CO2 Problem

Last night, I attended a screening of the National Resources Defense Council’s  (NRDC) new film, “Acid Test:  The Global Challenge of Ocean Acidification.”  This 20 minute film is definitely worth the time to watch, and the NRDC has generously allowed free distribution.  I hope you’ll take a little time to watch it.

Usually we’re focusing on CO2 as the man-made cause of climate change – we burn various types of fossil fuel (releasing a molecule called CO2 or carbon dioxide) which leads to changes in our atmosphere and an average increase in long-term global temperatures.  But, as is shown in this film, there’s another impact of CO2 emissions.  When CO2 accumulates in the atmosphere, it often enters the ocean as well.  In the ocean, CO2 reacts with water to form carbonic acid.  The NRDC states, “Since the start of the Industrial Revolution about 150 years ago, approximately one-quarter  to one-third of all CO2 from fossil fuels – or about 500 billion tons – has been absorbed by the seas, increasing the average acidity by 30 percent.”

Now, you may have the same reaction that I did – sure, 500 billion tons is a lot, but the oceans are pretty darn big too.  I mean, they can be as deep as 5,000 meters.  Fortunately, the local chapter of the Sierra Club, which sponsored the film screening, invited a local oceans expert from George Mason University to answer some questions.  He explained that the portion of the ocean that we most commonly encounter is the top 200 meters.  That’s where we find most of the sea life on which we depend.  That’s where fluctuations in currents impact our climate and weather.  So 500 billion tons into the top 200 meters can have a very substantial effect on the health of our oceans. 

Ocean acidification affects the many species of animals that build exoskeletons, or external shells or skeletons.  These animals need carbonate (another molecule) from which they build these exoskeletons.  The availability of carbonate is negatively affected by an increase in ocean acidity (or a drop in pH).  If ocean acidity gets high enough, the environment can even become corrosive to the shells of these organisms.  The worry is that many of these species could become depleted or even extinct.

But what if you’re not really interested in ocean ecology?  Who really gives a flying flit if a few little invertebrates can’t make shells?  Well, those little invertebrates are the basis of the ocean food chain.  Little animals get eaten by bigger animals, which get eaten by bigger animals.  Humans are part of this food chain.  The reason to care, if you’re not concerned about species extinction and nature in general, is that your food source could be severely impacted.  For great information on worldwide fisheries, check out UN Food and Agriculture, Fisheries and Aquaculture Department.

The NRDC makes some suggestions for greenmomsters who want to do their part in turning around this damage to our oceans:
  • encourage your local, state, and federal government to adopt an energy policy that invests in efficiency and encourages renewable sources based on wind and sun;
  • encourage the federal government to establish a strong national policy to protect, maintain, and restore the health of marine ecosystems, end overfishing, and create marine protected areas;
  • do your part to reduce use of fossil fuels through conservation at home and on the road.

Any comments on the film?

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