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by David Suzuki
Living in cities, it’s easy to forget about our connection to
the natural world. In human-created environments, surrounded by concrete
and asphalt, we often feel isolated and insular - as though we are
protected from the forces of nature.
In some ways, we are more protected, but in other ways our cities
can actually make us more vulnerable. Consider climate change. A recent
report from the Harvard Medical School looked at how human-induced
changes to the Earth’s atmosphere affect the health of people
living in cities. And the conclusions weren’t comforting.
It turns out that all the carbon dioxide and pollutants we are pumping
out through our tailpipes and smokestacks doesn’t dissipate
as readily as had been previously thought. In fact, much of the carbon
dioxide (the primary heat-trapping gas) pretty much stays put, creating
a “dome” of it over our cities.
This does two things. First, it intensifies the urban “heat-island
effect” - that is, the tendency of cities to be warmer than
rural areas because of all their infrastructure, pavement and lack
of green space. Higher carbon dioxide concentrations add to this effect,
making cities up to several degrees warmer than surrounding areas
- similar to being in a crowded room with the windows closed.
In addition, the extra carbon dioxide increases plant growth - particularly
for opportunistic species that thrive in cities, such as ragweed.
Pollen from these plants, along with spores from fungi, are potent
allergens and can exacerbate asthma. Both fungi and ragweed are expected
to thrive in cities as our climate warms.
Making the situation worse is “particulate” pollution.
This is the black soot that comes out of tailpipes - especially from
diesel vehicles. Particulates have been known to be a problem for
some time because they can clog airways and even cause lung cancer.
But the Harvard researchers point out that it is a bigger problem
when combined with other allergens like pollen and mould because tiny
bits of particulate help deliver these allergens deep into our lungs.
As the researchers say: “Air pollution will act synergistically
with the allergens to further deteriorate respiratory health.”
This is a big concern, particularly for children and the elderly,
and it may help explain why the incidence of childhood asthma has
climbed steadily in recent years. In Canada, childhood asthma rates
increased from 2.5 percent in 1978 to 11.2 percent in 1995. Polluted
urban areas have the highest rates of childhood asthma. One-quarter
of all children living in Harlem, for example, suffer from the disease.
The cost of treating childhood asthma in the US is now estimated at
$3.2 billion per year.
According to the Harvard paper, increased heatwaves (like the one
that killed 35,000 people in Europe last summer), the spread of infectious
diseases (like West Nile virus), and severe storms will further jeopardize
human health in our cities as our climate warms. However, the authors
also point out that many of the solutions to climate change, like
improving energy and fuel efficiency, providing better transit options
and creating more green spaces, all have the added benefit of making
our cities more livable too.
That’s something to consider when we fill up our cars at the
pump. Fuel prices may seem to have skyrocketed, but gasoline is still
cheaper than bottled water or milk. And burning vast amounts of it
obviously harms our health and quality of life. Rather than cutting
fuel taxes, we need to be focusing on finding ways to burn less gasoline.
As the report concludes, “developing alternatives to fossil
fuels is fundamental for the protection of public health.”
Climate change may be something that we think of as happening “out
there,” but it’s really happening right here in our back
yards. The sooner we start addressing the problem, the better off
we will be, because all the concrete and asphalt in the world can’t
keep the climate out.
Take the Nature Challenge and learn
more at www.davidsuzuki.org
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