POPULATION AND POLLUTION
The baby boom was in the 1950s when the American birthrate skyrocketed. When the socalled baby boomers were in their 20s, they were young and vibrant, and they added to
American productivity. Today, however, the boomers are aging. Their children worry
that elderly boomers will drain resources, not to mention national attention, from younger
adults.
Human Population Growth
The world population increases the equivalent of a medium-sized city (200,000) every
day and the equivalent of a country the size of Germany (80 million) every year. Most of
the growth is coming from less-developed countries.
Right now, there are about 6 billion people on the planet, but in the next 100 years, there
will be about 8-11 billion. All populations need nutrients, space, water, and energy.
This means that in about 50 years, the world will need double the amount of food, jobs,
water, energy, and so on to maintain the same standard of living. Right now, half of our
world’s population do not have electricity or indoor water and cannot read even enough
to sign their name.
We are adding a billion more people to the planet much faster than we used to. We got
our first billion in 1800; the second billion arrived in 1930; the third billion in 1960; and
today there are 6 billion. Only if the growth rate continues to decline can there be zero
population growth when births equal deaths and the population size remains steady.
The More-Developed Versus Less-Developed Countries
The MDCs of North America, Canada, England, and Europe, have a population
growth under control and the people enjoy a good standard of living. The LDCs of
South America, Africa, and Asia, have population growth out of control and the
majority of people live in poverty.
The term “third-world countries” is an old term used to mean the less-developed
countries. This term was introduced by those who thought of the United States and
Europe as the first world and the former USSR as the second world.
The MDCs doubled their populations between 1850 and 1950 because of a decline in the
death rate and modern medicines. The populations of a few of the MDCs, Italy, Denmark,
Hungary, Sweden are actually decreasing in size. In contrast, there is no leveling off and
no end in sight to U.S. population growth.
Although the death rate began to decline steeply in the LDCs following World War II
with the importation of modern medicine from the MDCs, the birthrate remained high.
Comparing Age Structure
One way of characterizing population is by age groups. If there are more young women
entering the reproductive years than there are older women leaving them, there will still
be an increase in population. Most LDCs have a large proportion of young women under
the age of 15.
Possible Solutions
1. Establish and/or strengthen family planning programs.
2. Use social progress to reduce the desire for large families by providing education,
raising the status of women, and reducing child mortality rate.
3. Delay the onset of childbearing by five years and wider spacing of births.
The Human Population and Pollution
Intact ecosystems naturally prevent soil erosion, dispose of environmental wastes,
provide fresh water, regulate climate. But as the human population increases in size,
more ecosystems are impacted by humans. Ecosystems are no longer able to process and
rid the biosphere of wastes and leads to problems for all living things, and also problems
in the air, in the water, and on land.
Air pollutants in particular are involved in causing major environmental effects, including
global warming, acid rain, and ozone depletion. These terms are used on the news all the
time, so I thought I’d tell you a little about what that means.
FOSSIL FUELS
Problems with the use of fossil fuels such as coal and oil and gas include the fact that
they are nonrenewable, they pollute the environment when they are burned, oil and
gas wells pollute the environment by emitting greenhouse gases, and they are
contributing to the problem of global warming. The trend for the future is the use
of hydrogen for energy.
Hydrogen-based fuel cells are in use now in some cities to power vehicles, can be
produced locally all over the world, and will reduce global warming and air
pollution
Global Warming
One concern is that the world’s overall temperature, called the global climate will
continue to warm at a rate ten times faster than any time in the past.
There is more carbon dioxide in the air from the burning of fossil fuels and the
burning and clearing of forests to make way for farmland and pasture. The oceans are
currently absorbing about one half of the carbon dioxide emitted, or else the increase
would he much higher than this stated amount. In addition, methane gas is being given
off by oil wells, rice paddies, and all sorts of organisms including domesticated cows, and
this also contributes to global warming.
These gases are known as greenhouse gases because just like the panes of a greenhouse
they allow the sun’s radiation to pass through but hinder the escape of heat. Actually,
water is also a greenhouse gas because clouds do the same thing. If the earth’s
temperature rises due to the greenhouse effect, more water will evaporate, forming
more clouds, compounding the problem.
Predicted Consequences
Global warming will bring about climate changes, glaciers would melt, and sea levels
will rise, evaporation will increase, and most likely there will be more rain along the
coasts and dryer conditions inland. There will be more droughts inland, which will
reduce crop yields and also cause trees to die off. Billions will have to be spent to keep
coastal cities, like New York, Boston, and Miami from disappearing into the sea.
Acid Rain
Pure water has a pH of 7 but the small amount of carbon dioxide in the atmosphere
combines with water to produce a weak acid. Therefore, we get rain with an acid
pH. In addition, coal and oil that is burned will release sulfur dioxide into the air. The oil
well fires started during the Persian Gulf War released much sulfur dioxide into the atmosphere. Automobile exhaust puts nitrogen oxides in the air. Both sulfur dioxide and
nitrogen oxides are converted to acids when they combine with water vapor in the
atmosphere. That gives the rain an even more acid pH.
When the soil absorbs this rain, it becomes acidic too, and it causes forests to die, and
the waters cannot support normal fish populations.
The acid rain also corrodes marble, metal, and stonework, an effect that is noticeable
in cities.
Ozone layer
Ozone is a naturally occurring substance that is supposed to stay up high in our
atmosphere and absorbs the harmful ultraviolet radiation that tries to enter our
planet. However, we are now getting ozone forming down lower where we breathe. The
air pollutants from fossil fuels react with one another in the presence of sunlight to
produce ozone.
Breathing ozone affects the respiratory and nervous systems, resulting in respiratory
distress, headache, and exhaustion. These symptoms are particularly apt to appear in
young people; therefore, in Los Angeles, where ozone levels are often high,
schoolchildren must remain inside the school building. Ozone also damages plants.
Carbon monoxide from car exhaust blocks the hemoglobin in our blood from carrying
oxygen. Breathing large quantities of automobile exhaust can even result in death
because of this effect. Carbon monoxide is released into the air from the burning of
tropical forests.
Normally, warm air near the ground escapes into the atmosphere. However smog
keeps cold air at ground level beneath a layer of warm air above. This is particularly true
of Los Angeles, and that’s why it’s called the “air pollution capital” of the United States.
Ozone Depletion: When the ozone in the upper part of our atmosphere becomes depleted,
UV radiation impairs crop and tree growth and also kills plankton (microscopic plant and
animal life) that sustain oceanic life. Without an adequate ozone shield, food sources and
health are threatened. UV radiation also causes mutations that can lead to skin cancer,
cataracts, and affect our immune system.
Pollution of Oceans
Pesticides and other chemicals get into the ground and water supply, and new plants
absorb them, animals eat the plants, and humans eat the plants and the animals. In that
way, our bodies pick up these toxins.
The oceans are the final receptors for water pollutants carried by rivers. Waste
products that are dumped into areas that drain into the ocean can also be washed back to
shores. The plastic piece that holds a six-pack of cans, gets tangled in birds, fishes, and
marine mammals, causing their death.
Oil spills in the ocean kill plankton, fish, and shellfish, as well as birds and marine mammals. The largest tanker spill in U.S. territorial waters occurred on March 24, 1989, when
the tanker Exxon Valdez struck a reef in Alaska and leaked 44 million liters of crude oil.
Soil Erosion, Desertification, and Deforestation
Soil Erosion
Wind and rain carry away about 25 billion tons of topsoil yearly, worldwide. If this rate
of loss continues, the earth will lose practically all of its topsoil by the middle of the next
century. This is compounded by increased use of fertilizers, pesticides, and fossil fuel
energy. One solution is for farmers to use different cropping methods to control soil
erosion.
Desertification the transformation of land to desert conditions because of
overgrazing and over-farming. It is particularly a problem along the edge of the Sahara
Desert in Africa, but occurs in the US as well.
Deforestation
Removal of forests impacts the amount of carbon dioxide in the atmosphere, the
amount of fresh water available, and the retention of soil. Yet, a huge number of
trees have been turned into paper and wood products. The animals that live in these
forests have been displaced.
Habitat loss is of most concern in tropical rain forests and coral reefs. Tropical rain
forests are home to more wildlife than temperate forests.
For example, temperate forests across the entire United States contain about 400 tree
species compared to 750 types of trees in the rain forests. There are about twice as many
fish, frogs, and birds in a rain forest. A million species of plants and animals are in
danger of disappearing within 20 years as a result of deforestation.
Many of these life-forms have never been studied, and yet they may be useful
sources of food or medicines.
Logging occurs because people prefer furniture made from tropical woods. In Brazil, the
government allows citizens to own any land they clear in the Amazon forest. Once the
cleared land is incapable of sustaining crops, the farmers move on to another part of the
rain forest. In the meantime, cattle ranchers move in and keep the area deforested.
Extinction
Hunting causes a lot of problems. Animals are being hunted on land and water for both
pleasure and profit.
Another major cause of extinction is habitat destruction outright or by fragmentation
into small pieces that cannot support the same species richness as before. By the year
2010, very little undisturbed rain forest will exist outside of national parks and other
relatively small protected areas.
The accidental or purposeful introduction of new species into an ecosystem can cause
the extinction of another species. The brown tree snake somehow slipped into Guam from
the Pacific islands in the late 1940s. Since then, it has wiped out 9 of 11 native bird
species, leaving the forests eerily quiet.
Pollution like pesticides has caused decreased predatory birds and amphibians. The
loss of entire species will most likely be detrimental to humans since they depend on
them for raw materials, food, medicines, and other things.
Natural Medicines
Great benefits can come from unlikely species. The Gila monster has deadly saliva, but
it is useful at regulating insulin levels in diabetics. The vampire bat has substances in its
salivary glands that prevent clotting, and are found to break up clots in stroke victims.
The scorpion’s venom can seek out and destroy brain tumors. The puffer fish has
poisonous spines but are effective in easing the pain of heroine withdrawal and cancer.
The saliva of the leech can reduce the risk of blood clots during surgeries. The poisonous
frog has deadly skin secretions, but is effective as a pain killer without being addictive.
Coral Reefs
Like a tropical forest, coral reefs are most likely sources of new medicines yet to be
discovered. If we lose one species, we may be losing an important, life-saving medicine.
Not only that, a reef serves as a storm barrier that protects the shoreline and provides a safe harbor for ships.
Reefs around the globe are being destroyed. Tons of soil from deforested tracts of land
brings nutrients that stimulate the growth of all kinds of algae. This has contributed to
population explosion of starfish that are devouring Australia’s Great Barrier Reef. Reefs
are also being damaged by pollutants that seep into the sea.
About 90 % of the coral reefs of the Philippines are dead or deteriorating due to overfishing. The methods are sinister, including the use of dynamite to kill the fish, making it
easier to scoop them up, and use of cyanide to stun the fish to capture them alive. The
seaweed overgrows and kills the coral. It is estimated that we may lose 60% of all coral
reefs in the next 50 years.