Environmental Engineering Reference
In-Depth Information
failed to discover a 'Northwest Passage' through the Arctic. The last of these became a
cause célèbre in Britain when the two ships led by Sir John Franklin disappeared. Several
further ships were lost searching for Franklin and his crew. In 1903-1906 an expedition
led by Roald Amundsen finally made it through in a small shallow-bottomed ship, but the
Northwest Passage remained impassable for commercial shipping for another century. In
2008, a Canadian shipping company, Nunavut Sealift and Supply, announced the start of
year-round cargo services from Montreal to Western Canada. Some scientists now predict
that, within the next forty years, John Franklin's frozen grave will be as busy a commercial
China, with characteristic pragmatism, is hedging its bets on energy. While rapidly
expanding its coal power capacity, it has also invested heavily in hydropower. However,
radical changes in weather have thrown a spanner in the works. In September 2011, many
of China's rivers ran with less than 20 per cent of their normal water flow, and the nation's
hydroelectric power output fell proportionally. The Chinese government has not provided
an official opinion, but, according to Lin Boqiang, director of the China Center for Energy
Economics Research at Xiamen University, “if climate change caused this year's water
flow decreases, which I think it did, then its impact will be long-term. It will take a toll on
There is no shortage of evidence, nor of anecdotes, pointing to a change in the Earth's
climate. The term 'climate change' sounds oddly vague, 'change' being open to
interpretation, and more suggestive of a political slogan than a scientific hypothesis. Yet
ambiguity is at the very heart ofthe matter.The coalition ofbusiness interests, conservative
politicians, and conspiracy theorists who deny or downplay climate change has latched on
to this uncertainty, in much the same way that religious 'creationists' insist that evolution
is only a 'theory'. The problem with predicting the exact nature of climate change is that
so many variables are involved. While we have reliable data showing that the average
temperature ofthe Earth'satmosphere andoceans isrising, noonereally knowswhat effect
this will have on climate, other than that it will change; the greater the rise in temperature,
the more radical that change. But why is the Earth getting warmer, what is the cause, and
what can we do to offset or 'mitigate' the change? In the end, it all comes down to our
relationship with the sun.
Solar radiation travels to Earth and breaks in through the atmosphere. Certain gases in
the atmosphere immediately reflect a part of the radiation back into space. The rest is either
absorbed by our atmosphere - its energy driving wind, waves, and weather - or reaches
the ground and heats the Earth's surface. When it first enters the atmosphere, the solar
radiation loses energy, its waves becoming longer (mostly in the infrared spectrum) and
less intense. Having lost much of its energy, it is less able to penetrate the atmosphere on
