Earth Talk: The impact of human population growth on global warming

August 5, 2009

Dear EarthTalk: To what extent does human population growth impact global warming, and what can be done about it?

—Larry LeDoux, Honolulu, Hawaii

No doubt human population growth is a major contributor to global warming, given that humans use fossil fuels to power their increasingly mechanized lifestyles. More people means more demand for oil, gas, coal and other fuels mined or drilled from below the Earth’s surface that, when burned, spew enough carbon dioxide (CO2) into the atmosphere to trap warm air inside like a greenhouse.

According to the United Nations Population Fund, human population grew from 1.6 billion to 6.1 billion people during the course of the 20th century. (Think about it: It took all of time for population to reach 1.6 billion; then, it shot to 6.1 billion over just 100 years.) During that time, emissions of CO2, the leading greenhouse gas, grew 12-fold. And with worldwide population expected to surpass 9 billion over the next 50 years, environmentalists and others are worried about the ability of the planet to withstand the added load of greenhouse gases entering the atmosphere and wreaking havoc on ecosystems down below.

Developed countries consume the lion’s share of fossil fuels. The United States, for example, contains just 5 percent of world population, yet contributes a quarter of total CO2 output. But while population growth is stagnant or dropping in most developed countries (except for the U.S., because of immigration), it is rising rapidly in quickly industrializing developing nations. According to the United Nations Population Fund, fast-growing developing countries (like China and India) will contribute more than half of global CO2 emissions by 2050, leading some to wonder if all of the efforts being made to curb U.S. emissions will be erased by other countries’ adoption of our long-held over-consumptive ways.

“Population, global warming and consumption patterns are inextricably linked in their collective global environmental impact,” reports the Global Population and Environment Program at the non-profit Sierra Club. “As developing countries’ contribution to global emissions grows, population size and growth rates will become significant factors in magnifying the impacts of global warming.”

According to the Worldwatch Institute, a nonprofit environmental think tank, the overriding challenges facing our global civilization are to curtail climate change and slow population growth.

“Success on these two fronts would make other challenges, such as reversing the deforestation of Earth, stabilizing water tables, and protecting plant and animal diversity, much more manageable,” reports the group. “If we cannot stabilize climate and we cannot stabilize population, there is not an ecosystem on Earth that we can save.”

Many population experts believe the answer lies in improving the health of women and children in developing nations. By reducing poverty and infant mortality, increasing women’s and girls’ access to basic human rights (health care, education, economic opportunity), educating women about birth control options and ensuring access to voluntary family planning services, women will choose to limit family size.

CONTACTS: United Nations Population Fund,; Sierra Club’s Global Population and Environment Program,; Worldwatch Institute,

SEND YOUR ENVIRONMENTAL QUESTIONS TO: EarthTalk, P.O. Box 5098, Westport, CT 06881; Read past columns at: EarthTalk is now a book! Details and ordering information at:

from the August 5 – 11, 2009 issue


  1. margaret

    August 20, 2009 at 12:48 am

    I recently came across your blog and have been reading along. I thought I would leave my first comment. I don’t know what to say except that I have enjoyed reading. Nice blog. I will keep visiting this blog very often.


  2. Alemu Ayalew

    April 3, 2010 at 4:59 am

    I am from Ethiopia , Addis Ababa Univesity from the department of Geography and Environmental studies as a major and population studies as a minor; I have an excellent theoretical and practical knowledge about how population and environment are related; and i always wishes population to have a friendly living with environment.All peoples of our planet; please, lets have a long live environment until our life time. It is a big issue that we have to say something about it every day in our LIFETIME.
    Thank you!
    Mobile ; +2519 10 11 77 37

  3. sacha davilak

    July 13, 2011 at 7:33 pm

    You might like to read George Monbiot’s take on population – Stop blaming the poor. It’s the wally yachters who are burning the planet

    Population growth is not a problem – it’s among those who consume the least. So why isn’t anyone targeting the very rich?

    Monbiot goes on to say: While there’s a weak correlation between global warming and population growth, there’s a strong correlation between global warming and wealth.

    The obsessives could argue that the people breeding rapidly today might one day become richer. But as the super wealthy grab an ever greater share and resources begin to run dry, this, for most of the very poor, is a diminishing prospect

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