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Acid rain eating away at forests, chemicals from far away
collecting in Arctic animals, changes in the chemistry of
seawater, a mysterious virus from overseas—they’re distress
calls from a planet where pollution is an increasingly
global problem. |
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Picture yourself in a large, locked room. Now imagine that
someone at the other end is setting off smoke bombs. At
first, you might barely see or smell the smoke. Sooner or
later, though, it will make its way toward you. Since the
room is locked, you have no way to escape.
That’s basically the situation we’re all in when it comes to
polluting our planet. Earth is large, yes, but it’s not
infinite. Moreover, it’s a closed system. Whatever we pump
into our air or water stays with us. More and more often,
that’s causing global problems. Pollution from one place can
make trouble hundreds or even thousands of miles away. This
is called transboundary pollution.
It’s tempting, when reading about an environmental issue in
some distant state or foreign land, to think, “Well, that’s
not my problem.” In an increasingly globalized world,
however, that thought rings less and less true. It’s growing
ever clearer that problems in one place can affect distant
environments and people. Here are just a few examples of
what’s happening.
NASTY RAIN
Some years ago, Canadians noticed that many of their forests
were dying. Something was hurting the trees, but what? The
answer lay to the south—power plants in the United States.
To generate energy, the plants burned fossil fuels. That
released nitrogen and
sulfur into the air. These
chemicals
combined with water vapor in clouds to form
acid rain.
Something similar—acid rain hurting faraway forests—occurs
all over the world.
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The power plants that provide
electricity for the buildings in this image also release
chemicals that produce acid rain.
Source:
Environmental Protection Agency |
Acid rain is not pure acid, of course. But it’s far more
acidic than ordinary rain. The acid causes damage wherever
the rain falls. Trees start to die. Lake water turns acidic,
harming the plants and animals that live in them. Stone
buildings suffer erosion. All because of pollutants that
might have been released in other nations.
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Bioaccumulation basics: Tiny creatures eat or absorb pollutants.
Small fish eat the tiny creatures. Larger fish eat the small fish. Seals and whales eat the
larger fish. Polar bears eat the seals. Thus pollutants climb up the food chain.
Source:
Columbia University |
UNHEALTHY ARCTIC IMPORTS
Recently, scientists noticed that large amounts of
organochlorine compounds and
heavy metals are collecting in
the bodies of Arctic creatures. This is called
bioaccumulation. And the chemicals are not good for the
animals.
The strange thing is, the Arctic has few people or sources
of pollution. So these contaminants must have traveled there
from other places. They were carried north by wind and
water. Some of the contaminants, for example, began as
ingredients in pesticides used on crops in the United States
and Canada.
DEEP TROUBLE
Oceans cover 70 percent of our globe. So vast are the seas
that people once thought they could absorb anything we
dumped into them. So dump we did. Humans have pumped
enormous amounts of sewage and industrial pollution into the
oceans. In addition, runoff from farms has carried
pesticides and other chemicals into rivers, which in turn
flow into the oceans.
Besides taking in pollutants, the oceans are absorbing
carbon dioxide. Scientists estimate that the sea has
absorbed 500 billion tons of carbon dioxide since the start
of the Industrial Revolution. When the gas mixes with
seawater, it creates carbonic acid. That’s the weak acid
that gives soda pop its pop.
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This
NASA map shows carbon dioxide in the atmosphere.
The redder the area, the more carbon dioxide. Much of the gas will be absorbed by the world’s oceans. |
Today we’re learning that we were wrong about the oceans.
They can’t handle everything we dump in them. Pollutants and
carbon dioxide are having some alarming impacts. For
starters, the oceans are growing more acidic. Indeed,
scientists report they haven’t been this acidic in nearly a
million years. By 2100, the sea may be 2.5 times as acidic
as it was before the Industrial Revolution. If this trend
continues, countless fishes and other species could die out.
At the same time, the ocean’s changing chemistry is boosting
the growth of harmful bacteria and
algae. It’s almost as if
evolution is running in reverse, with simple
organisms
replacing complex ones. One oceanographer calls this the
“rise of slime.” Sounds gross, doesn’t it. Problem is, it
can be harmful too.
One can see the problem vividly along the coast of Sweden
each summer. Masses of bacteria gather in the Baltic Sea,
turning the water into what locals call “rhubarb soup.” This
not-so-tasty dish features dead fish bobbing in yellowish
water. Its ugly aroma taunts the eyes and lungs of people
who come too close. Something similar happens along
America’s coasts.
Red tides, once rare in Florida and
California have become common, boosting the number of people
going to the hospital with ailments from eating contaminated
fish and shellfish or with respiratory problems.
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A red tide hits the California coast.
Source:
NOAA |
A BIOLOGICAL MYSTERY
Since at least 2003, a mysterious killer has been stalking
the Great Lakes. It’s a virus that causes internal bleeding
and organ failure in fish. (It is not harmful to people.)
The virus has killed tens of thousands of fish and threatens
the survival of two dozen species.
So where does the virus come from? That’s the mystery.
Scientists know, though, where it does not come from—North
America. Somehow the virus made its way to the Great Lakes
from another continent. One theory is that it came in water
carried and dumped by ships from other places.
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Small World Home |
What Is Globalization?
People and Diseases |
Trade | Pollution |
Bioterrorism
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Watching America’s spacious skies turn
