- In this continuing series, editor Marilyn Hempel of www.populationpress.org ,
entertained Dr. David Pimentel of Cornell University. David
Pimentel is a professor of ecology and agricultural science at the College
of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853-0901.
His Ph.D. is from Cornell University. His research spans the fields of
basic population ecology, ecological and economic aspects of pest control,
biological control, biotechnology, sustainable agriculture, land and water
conservation, natural resource management, and environmental policy. Pimentel
has published more than 490 scientific papers and 20 books.
- As the United States accelerates toward adding 100 million
within the next 25 years, most Americans lack any understanding of the
consequences. This series continues to enlighten and create discussion
which may lead to debate.
- "HOW MANY AMERICANS CAN THE EARTH SUPPORT?" By
Dr. David Pimentel, Cornell University
- "Based on the current growth rate, the present U.S.
population of more than 270 million (310 million as of August 2010) is
projected to double to 540 million within the next 70 years. In addition,
the world population -- about 6.8 billion -- is projected to double within
just 50 years (again, based on current rates of growth). The growing imbalance
between the increasing world population and the finite amount of Earth's
resources that support human life is reason for grave concern.
- "Consider that according the World Health Organization,
more than 3 billion people are currently considered malnourished. This
represents the largest number and proportion of malnourished humans ever
in history! Deaths from malnutrition and other diseases have significantly
increased, especially during the past decade, and there is no indication
that this trend will cease or reverse. What can we expect as population
numbers continue to climb?
- "In order to support increasing numbers of people,
we will need to be able to feed them. The production of adequate food depends
on ample supplies of fertile cropland, pure water, energy, and other biological
resources, like plants and pollinators. Growing numbers of humans, though,
force us to stretch these limited resources further and further. The fact
that grain production -- which supplies 80% to 90% of the world food --
has been declining since 1983 should alert us to the potential for future
food supply problems and increasing malnutrition.
- "About 0.5 hectares (1.2 acres) of cropland per
person is required to provide a diverse diet similar to that desired by
the average American and European. At present, this amount of land is still
available in the United States for its present population. In contrast,
worldwide, only 0.27 ha of cropland per person remains for food production.
Since land is a finite resource, available cropland per person will continue
to decline, both worldwide and in the United States, as the human population
increases. Urban sprawl, highways, and industries also spread and cover
more land. Finally, a substantial amount of fertile cropland is lost to
erosion by wind and water every year. Some 10 million hectares of cropland
is being eroded and abandoned each year throughout the world.
- "Rainfall, as well as water captured in rivers and
lakes, is essential for all plants, including crops. As agricultural production
increases to feed more humans, pressure on water supplies also increases.
Because communities, states, and countries must share water, competition
for water resources increases. In arid regions of the world, which supply
30% of the world's food, irrigation has declined during the past decade.
This has already had a negative impact on food production in these regions.
Even in some areas of the United States, sufficient water for crops and
people is becoming a serious problem. The fact that the great Agualla aquifer
of central United States is being depleted about 140% faster than rainfall
recharges it, suggests an impending serious water scarcity for a large
area of U.S. land.
- "In addition to land and water resources, energy
is also vital to crop production. Solar energy and human power, augmented
with fossil energy, make the cultivation of crops possible. Fossil energy
is used to power farm machinery and irrigation pumps as well as to produce
fertilizers and pesticides. Unfortunately, fossil energy is a finite and
non-renewable resource that is being rapidly depleted throughout the world.
- "Lastly, humans and their assorted activities are
reducing biodiversity throughout the world. Pollination, essential for
one-third of the world's food supply and dependent on diverse species of
pollinators, has been declining; some U.S. crops already face serious problems
due to lack of sufficient pollination. The stability of other essential
biological resources for agriculture and forestry, such as microbes and
invertebrates, are also declining and being threatened due to human activities.
Finally, the use of more than 100,000 different chemicals -- including
pesticides -- worldwide reduces vital biodiversity even further.
- "As increasing numbers of humans travel and trade
more, more exotic species of plants and animals invade the U.S. and other
ecosystems worldwide. Some of these exotic species become pests, which
can increase food losses and frequently alter natural habitats. >From
40% to 80% of agricultural pests are biological invaders, and -- despite
the 5 billion pounds of pesticide applied worldwide -- more than 40% of
potential food is destroyed by pests each year.
- "At present, humans face serious malnutrition, land
degradation, water pollution and shortages, and declining fossil energy
resources. In addition, with related changes in the natural environment,
many thousands of species are being lost forever. If the human population
increases dramatically over the next several decades, as it is projected
to do, the strains on these limited resources will grow as well.
- "Some people are starting to ask just how many people
the Earth can support if we want to cease degrading the environment and
move to a sustainable solar energy system? There is no solid answer yet,
but the best estimate is that Earth can support about 1 to 2 billion people
with an American Standard of living, good health, nutrition, prosperity,
personal dignity and freedom. This estimate suggests an optimal U.S. population
of 100 to 200 million. To achieve this goal, humans must first stabilize
their population and then gradually reduce their numbers to achieve a sustainable
society in terms of both economics and environmental resources. With fair
policies and realistic incentives, such a reduction in the human population
can be achieved over the next century."
- Contact Marilyn Hempel at www.PopulationPress.org or email@example.com .
By snail mail: Blue Planet United, POB 7918 Redlands, CA 92375
- Frosty Wooldridge has bicycled across six continents
- from the Arctic to the South Pole - as well as six times across the USA,
coast to coast and border to border. In 2005, he bicycled from the Arctic
Circle, Norway to Athens, Greece. He presents "The Coming Population
Crisis in America: and what you can do about it" to civic clubs, church
groups, high schools and colleges. He works to bring about sensible world
population balance atwww.frostywooldridge.com He is the author of: America
on the Brink: The Next Added 100 Million Americans. Copies available: 1
888 280 7715