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From: cris |
Date:
June 10th, 2011 02:58 pm (UTC)
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few theories:
1) in order to gauge impact, you need to be able to assess a 'before' picture and an 'after'; and, afaik, there isn't a lot of 'before' data as studying the impacts of pollution and footprints of civilization wasn't a common thing until the 60's. What we do know is usually pieced together from commercial records (ie. the amount of cod fished off the Grand Banks and price thereof between 1940 and 1950 can be used to interpret supply and health of fish population at the time) but even such things can be notoriously noisy (ie. was the price high because cod were hard to find as they were choking on oil, or because there was a war on?)
b) there's a lot of trash in the oceans. Tanker wrecks, broken subs, crashed planes, freaking nuclear bomb tests. I imagine it would be hard to isolate the environmental impact of just one of those factors, especially over a large area. The Globe story is about a relatively small area of marshland that was impacted by a distinct event.
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