The Debate on Global Warming

The Debate on Global Warming
The surface of the earth has been warming, the average temperature increasing, for several years. People studying this do not agree on the cause of the warming trend. Some say that man has caused the change; others claim that it is a natural trend. For several years believers and skeptics have argued about the causes of global warming. The problem is complicated because believers warn that man-made causes if left to advance too far may be irreversible. Reduction of the rainforests, continued growth in hydrocarbon industries, increases in livestock, and depletion of the ozone are all considered factors in the debate. Skeptics maintain that the climate change is a natural phenomenon, that man?s effect on nature is largely overrated. The fact is that for several years, the earth?s temperature is rising. The problem remains in deciding what if anything we can do about it. -The simplest solution is an old one: conservation. Each gallon of gasoline releases 8.64 kg of CO2 into the atmosphere (source usepa)
Each kilowatt of electricity generated by a coal-fired plant produces about 1.4 kg of CO2 (source usepa). -Plant a tree. Forests cover 10 billion acres worldwide and sequester 1 trillion tons of carbon. The icpp estimates that 850 million acres could be made available for planting trees. These trees would take up 60 to 90 billion tons of carbon by the year 2050. Unfortunately, this is only 12 to 15% of projected emissions during this period. Moreover, trees mature and stop rapidly consuming carbon. They are cut down, burned, or decay, which releases their stored CO2. So trees are a temporary partial solution at best. However, if these trees were used for lumber or paper products, their carbon would be stored for much longer periods of time. This might give the next solution time to work. -John Martin, a scientist at Moss Landing Marine Laboratories in California, proposed in 1986 that we seed the oceans with iron to cause phytoplankton blooms. Such blooms would consume huge quantities of CO2, and when the plankton die in a couple of weeks they would sink to the bottom and thus sequester their CO2. Two small trial experiments have shown that it might work. The environmental impact on other creatures in the ocean has yet to be assessed. -To counter sea level rises, add snow to the east Antarctic ice sheet. The 3 trillion tons of sea water needed each year would be sprayed out as snow on the ice cap, using technology much like ski slopes use to make artificial snow. Oil kills birds in many ways. Its first effect is to break down the birds? waterproofing. Water runs off a duck?s back because the bird is protected by a layer of feathers, overlapping like the tiles on a roof (see sketch). Their fine structure makes them waterproof. The separate strands, or barbs, in each feather are bound together by rows of tiny hooks, or barbules, into a tight weave, like the cloth of a raincoat, that water cannot penetrate. Oil spills in Canadian waters Nº Spill Amount spilled Number of seabirds killed 1 Cap Tourmente ? Fall 1963 5 t Contaminated 140 ha of marsh, important habitat of Greater Snow Geese at that time of year 2 Arrow ? February 1970 9 000 t Offshore: more than 4 800, mostly murres and Dovekies; Inshore: more that 2 400, including diving ducks, Grebes and murres 3 Irving Whale ? March 1970 30 t About 5 000, mostly eiders 4 Eastern Lake Erie ? December 1975 Unknown 2 800, mostly diving ducks 5 Kurdistan ? March 1979 7 900 t 4 000, mostly murres and Dovekies 6 Nestucca ? December 1988 800 t 30 000 ? 40 000, mostly murres and auklets 7 Exxon Valdez ? March 1989 40 000 t More than 30 000, mostly diving ducks and auks 8 Placentia Bay ? Winter 1989-90 Unknown More than 17 500, mostly murres Oil pollution is not a problem we can leave until after the event, washing it away with new and improved cleaning technologies. Once the birds and beaches have been oiled, it is very difficult to restore them to their original state. Prevention is better than cure. -Dispersion by chemicals -Volunteer beach cleanup In the long run, however, we must change the way we think about the sea. It is not just a convenient dump for waste oil and other garbage, but a complex set of ecosystems whose well-being is central to the health of our planet. To help this understanding, Environment Canada publishes a multilingual brochure, ?Oil Kills Seabirds,? that is distributed to fishing boats and other ships in Newfoundland ports. It shows where seabirds are most vulnerable, and emphasizes that every oil spill, however small, is a potential hazard.

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