Dear EarthTalk: Green groups dont seem to discuss human population growth,
but I think the biggest issue confronting the planet is the collective demand we
put upon it. And what is the difference in impact between population growth in
Third World countries, which are poor, against that in the U.S., where we
consume and waste so much more? -- Ronald Marks, via e-mail
The global rate of human population growth peaked around 1963, but the number
of people living on Earthand sharing finite resources like water and foodhas
grown by more than two-thirds since then, topping out at over 6.6 billion today.
Human population is expected to exceed nine billion by 2050. Environmentalists
dont dispute that many if not all of the environmental problemsfrom climate
change to species loss to overzealous resource extractionare either caused or
exacerbated by population growth.
Trends such as the loss of half of the planets forests, the depletion of
most of its major fisheries, and the alteration of its atmosphere and climate
are closely related to the fact that human population expanded from mere
millions in prehistoric times to over six billion today, says Robert Engelman
of Population Action International.
According to Population Connection, population growth since 1950 is behind
the clearing of 80 percent of rainforests, the loss of tens of thousands of
plant and wildlife species, an increase in greenhouse gas emissions by some 400
percent and the development or commercialization of as much as half of the
Earths surface land. The group expects that half of the worlds population will
be exposed to water-stress or water-scarce conditions feared to intensify
difficulties in meetingconsumption levels, and wreak devastating effects on our
delicately balanced ecosystems in the coming decades.
In less developed countries, lack of access to birth control, as well as
cultural traditions that encourage women to stay home and have babies, lead to
rapid population growth. The result is ever increasing numbers of poor people
across Africa, the Middle East, Southeast Asia, and elsewhere suffering from
malnourishment, lack of clean water, overcrowding and inadequate shelter, and
AIDS and other diseases.
And while population numbers in most developed nations are leveling off or
diminishing today, high levels of consumption make for a huge drain on
resources. Americans, who represent only four percent of world population,
consume 25 percent of all resources. Industrialized countries also contribute
far more to climate change, ozone depletion and overfishing than developing
countries. And as more and more residents of developing countries get access to
Western media, or immigrate to the U.S., they want to emulate the
consumption-heavy lifestyles they see on their televisions and read about on the
Given the overlap of population growth and environmental problems, many would
like to see a change in U.S. policy on global family planning. In 2001, George
W. Bush instituted what some call the global gag rule, whereby foreign
organizations that provide or endorse abortions are denied funding support.
Environmentalists consider that stance to be shortsighted, that support for
family planning is the most effective way to check population growth and relieve
pressure on the planets environment accordingly.
CONTACTS: Population Action International,
Dear EarthTalk: How much of an effect, if any, does the carbon dioxide in
carbonated beverages have on global warming? -- Michael Holmes, Shenandoah, VA
A typical 12-ounce can of soda contains up to six grams (.013 pounds) of
carbon dioxide (CO2) gas, which either escapes into the atmosphere from the
liquid upon opening, or from your body after you consume the contents. So yes,
drinking carbonated beverages does contribute to your carbon footprint, but
only ever so slightly.
To provide some context, every time you burn a gallon of gas driving from
point A to B in your car, about 20 pounds of carbon dioxide wafts skyward (if
you find this hard to believe, visit the U.S. Department of Energys fuel
economy website at:
www.fueleconomy.gov/feg/co2.shtml). So, extrapolating out, a typical car
commute to work produces upwards of 700 times the greenhouse gases as drinking
that can of Coke.
But cans and bottles of carbonated (or non-carbonated) drinks are still no
friends of the environment. The production and distribution of single-serving
beverages of all kinds generates untold millions of tons of greenhouse gases and
other pollutants every year, while also wasting billions of gallons of fresh
water. And once the drinks have been consumed, all those cans and plastic
bottles have to go somewhere.
Some communities are diligent enough to capture more than half of all such
containers for recyclingan activity which itself generates significant amounts
of greenhouse gasesbut that still means that more than 40 billion cans are
ending up in landfills each year, or even worse, as litter, according to data
compiled by the non-profit Container Recycling Institute (CRI).
Each un-recycled can or bottle then must be replaced by an equivalent one
made from virgin materials. CRI reports that just the manufacture of these
replacement aluminum cans each year generates about 3.5 million tons of
greenhouse gas emissions, while also causing other environmental damage from the
extraction of the bauxite from which aluminum is made. Even a larger amount of
resources are used (petroleum-based in this case) and greenhouse gases emitted
from the significant number of plastic single-serving drink bottles that are
thrown away and not recycled each year.
Consumers can take a bite out of all this resource waste and pollution by
remembering that, first and foremost, water is the least costly and healthiest
beverage of all (on virtually all personal and ecological counts). And water
drawn from the kitchen faucet requires no disposable packaging or shipping to
get there, thanks to the highly efficient water-delivery systems that have been
in place in developed countries in the vast majority of communities for a very
For those who cannot get by without their soft drinkscarbonated or
otherwisethe best way to lower that carbon footprint is to buy them in large
containers and parse out servings in cups or glasses. A typical two-liter (67.6
ounce) plastic soda bottle holds five and a half times the liquid of a 12-ounce
container and over four times that of a 16-ounce container, so it is easy to
imagine the resource savings over time.
CONTACTS: Container Recycling Institute,
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