Dear EarthTalk: Green groups don’t 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 Earth – and sharing finite resources like water and food – has 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 don’t dispute that many if not all of the environmental problems – from climate change to species loss to overzealous resource extraction – are either caused or exacerbated by population growth.
Human population is expected to exceed nine billion by 2050, the result an ever-increasing number of poor people suffering from malnutrition, lack of clean water, overcrowding, inadequate shelter, AIDS and other diseases. Pictured here: Living conditions today in Srinagar, Kashmir, India. / Photo © Getty Images
"Trends such as the loss of half of the planet’s 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 Earth’s surface land. The group expects that half of the world’s population will be exposed to "water-stress" or "water-scarce" conditions feared to "intensify difficulties in meeting…consumption 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 Internet.
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 planet’s environment accordingly.