Recently I came across a very interesting study by the Cambridge university Press on what exactly is pollution all about.What it contained was not merely a collection of flowery terms and sugar coated text, but an earnest attempt to bring forth the facts of day to day advancement of pollution in everyday life, its impacts and our underestimated thinking about it.............
“The economy is a wholly owned subsidiary of the
environment. All economic activity is dependent upon
that environment with its underlying resource base.”
US Senator Gaylord Nelson on first Earth Day, 1970
What is pollution and why is it important? Why does pollution occur,
and is it harmful at all levels? What happens to pollutants in the
environment? What are the root causes of pollution?
Humans are massively changing the Earth
As described in an article in Science,1 Human domination of Earth’s
ecosystems, ‘‘Between one-third and one-half of the land surface has been transformed by human action; the carbon dioxide concentration
in the atmosphere has increased by nearly 30% since the beginning
oft he Industrial Revolution; more atmospheric nitrogen is now
fixed by humanity than by all natural terrestrial sources combined;
more than half of all accessible surface fresh water is put to use by
humanity; and about one-quarter oft he bird species on Earth have
been driven to extinction . . . All . . . trace to a single cause, the
growing scale oft he human enterprise. The rates, scales, kinds, and
combinations of changes occurring now are fundamentally different
from those at any other time in history; we are changing Earth more
rapidly than we are understanding it. In a very real sense, the world
is in our hands and how we handle it will determine its composition
and dynamics, and our fate.”
Nature’s services
In the past, we often did not even consider that we were changing
our environment, let alone how that could affect us. In the twentieth
century, many people willingly ignored gross pollution if its source
was a factory on which the community depended for employment.
‘‘That’s the smell of money” they might say. This still occurs in some
places in the world. If it took so long to recognize that pollution could
directly affect human health, think how difficult it is to recognize our
total dependence on the environment.
Protecting drinking water
Recently, New York City spent over a billion dollars to buy land to
its north in the Catskill Mountains in the watershed that provides
drinking water to New York City. The City then restricted how the
land could be used, forbidding activities that could pollute the watershed’s
streams and rivers. One action regulated was the application
of pesticides and fertilizers on land because these substances can run
off into local waters. By recognizing and protecting the Catskills’ natural
water filtration capability -- an ecosystem service -- the City avoided
having to build a treatment plant to purify its drinking water. The
plant would have cost about $6 billion, plus $300 million a year to
run. The City saved itself$5 billion.
Protecting ecosystem services
New York City protects much of the land it bought from development.Why?
- Trees and vegetation stabilize the soil preventing it from eroding during rainstorms, and being carried into Catskill streams as a pollutant.
- On undeveloped land, soil and tree and vegetation roots absorb rainwater lessening the risk of flooding during heavy rains.The water is instead slowly released to streams, while another portion seeps down into and replenishes groundwater.
- Undeveloped land acts as a home to wildlife and also provides timber, recreation and aesthetic value, and has the advantage of being cooler than cleared land.
- Its wetland areas also provide services. Aquatic plants and microorganisms purify polluted water carried into the wet lands with runoff. They trap eroded soil, preventing it from running into streams and lakes. Wetlands provide flood protection by serving as a sink during heavy rains.They also provide habitat to multiple bird and other species.
Not only rural, but city trees too provide valuable services. The organization
American Forests was concerned by the loss of tree canopy
in American cities. Using satellite and aerial imagery, they showed
that tree cover in 20 US cities had declined 30% over three decades.
This was disturbing: trees provide shade and cooling to the urban
buildings they shelter; they have aesthetic value; they trap polluted
storm water runoff via the soil held by their roots. And trees trap
air pollutants: they trap gaseous pollutants by the stomata in their
leaves; sticky or hairy leaves also filter particulates from air. Using a
computer-based geographic information system American Forests first
calculated how much air pollution urban trees remove, and then calculated
the economic loss of cutting the trees. In Washington, DC
trees lost to cutting would have removed about 354 000 lbs (over
160 000 kg) of major air pollutants including carbon monoxide, sulfur
dioxide, and ozone. This lost capacity costs the city about $1 million
a year in additional air pollution abatement expenses. And because
cut trees were not there to trap storm water, there was a 34% increase
in storm water runoff. It costs Washington, DC about $226 million
per year to process the additional runoff. Fortunately, the average
American city, despite its losses, still has about 30% tree cover.
American Forests believes that this could reasonably be increased to
at least 40%.
Other natural services
Ecosystems provide many services; a few of these services are outlined
in the following.
- Vegetation and trees absorb the greenhouse gas carbon dioxide, while releasing the oxygen necessary to our lives.
- The atmosphere’s stratospheric-ozone layer protects us from the sun’s strongest ultraviolet radiation.
- Worms and other organisms, and vegetation enhance the fertility of soils that we need for agriculture.
- Healthy ecosystems provide insects, birds, and other animals that pollinate plants (including crop plants). Birds and some insects also reduce many agricultural pests.
- Natural systems provide seafood, wild game, forage, wood, biomass fuels, and natural fibers.
- They degrade organic wastes, both naturally produced and human-produced waste.
“Less forgiving than our planet.”
Economists often argue that technology can substitute for natural life-support systems.
One experiment in the ability of technology to support life is Biosphere 2, an
enclosed man-made structure built as a model for a self-sustaining extraterrestrial
colony in space. Completed in 1991 at a cost of $200 million, its 3.15 acres (1.27 ha)
were a closed-off mini-Earth containing tiny biomes – a marsh from the Florida
Everglades, an equatorial rain forest, a coastal desert, a savanna with a stream and
grasses from three continents, an artificial mini-ocean with a coral reef, plus an
orchard and intensive agricultural area. Its underbelly holds a maze of plumbing,
generators, and tanks.
Eight people moved into the Biosphere 2 for 2 years. The first year went
well, but in the second crops failed, and people grew thin. They became dizzy
as atmospheric oxygen levels fell from 21% to 14% – a level typical of 14 000 ft
(4267 m) elevation. This occurred because excessive organic matter in the soil
absorbed oxygen from the air. Atmospheric carbon dioxide “spiked erratically,”
while nitrous oxide rose to levels that could impair brain function. Vines and algal
mats overgrew other vegetation. Water became polluted. The Biosphere initially
had 3800 plant and animal species. Among the 25 introduced vertebrate species, 19
died out and only a few birds survived. All the Biosphere’s pollinators – essential
to sustainable plant communities – also became extinct. Excitable “crazy” ants
destroyed most other insects.
Much was learned from Biosphere 2, which was taken over in 1997 by Columbia
University to be used as an educational facility in which Earth stewardship is fundamental
to the curriculum, a place to “build planetary managers of the future.”
Among its research efforts are long-term studies of the effects of various levels of
the greenhouse gas carbon dioxide on plant communities.
Someone noted that Biosphere 2 is less forgiving than our planet. But Earth
too is a closed system, a larger version of Biosphere 2. History records examples
of civilizations that failed or grew weak after having a severe impact upon their
local environment. But survivors often could move on to other environments.
Today, Earth’s huge population cannot “move on” although many people struggle
to immigrate to better locales. And people cannot, not in inexpensive ways available
to everyone, substitute technology for nature’s services. How does one substitute
for breathable air?
Degrading human wastes
Think about biodiversity, the fantastic variety of species of animals,
plants, and microorganisms in our world. Among these species are the
insects and worms, bacteria, and fungi that degrade natural wastes
and the wastes we discard -- the sewage, garbage, and other organic
wastes and pollutants. These waste-degrading creatures could live
without us, but we cannot live without them. Some larger creatures
eat wastes too -- vultures are essential for scavenging dead animals
in some places. Which species are absolutely vital to our lives? We cannot answer that question, but we do know that a great many are
needed to maintain ecosystem services. And we know that humanity
is, through habitat destruction and disruption and pollution, destroying
species at a rate perhaps 100 times faster than the natural rate
of extinction. And we know that scientists increasingly emphasize
that we are exceeding the capacity of some ecosystems to absorb our
wastes.
Assessing Earth’s ecosystems
Given that Earth’s ecosystems are vital to human lives we need to
know how those ecosystems are faring. What is the health of our
planet? In 2000 the United Nations Environment Program (UNEP)
assisted by about 1500 scientists, embarked on a worldwide study
the Millennium Ecosystem Assessment. Costing $5 million a year over
4 years, it is evaluating how well the planet’s ecosystems are functioning.
The ecosystems being monitored are: forests, inland waters
and coastlines, shrub lands, dry lands, deserts, agricultural lands, and
others. How well are they providing the ecosystem goods and services
that we expect oft hem including food, fiber, and clean water? How
are human actions affecting their capacity to provide these services?
The vitality of ecosystems is critical both to human life and health
and to the economic viability of nations. The Millennium Ecosystem
Assessment will provide reliable, scientifically reviewed information
on strengthening how we humans can better manage ecosystems
for our own use and for long-term sustainability. The assessment
received a great assist in the form of 16 000 photographs donated by
the US National Aeronautics and Space Administration (NASA). Taken
from space by satellite, the pictures show changes occurring in the
1990s in biomes as varied as coastlines, mountains, and agricultural
land.
