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Slowing population: Would it curb climate change?


Ever since belching smokestacks arose during the Industrial Revolution, greenhouse gases and human population have climbed in lockstep to higher and higher levels.

And while scientists warn that humanity must dramatically slash future carbon-dioxide emissions to avert extended droughts, floods and other climate catastrophes, they have generally avoided a rigorous examination of how slowing population growth would help. Now, an international team of scientists has done the math.

If global population were to grow by less than a billion by midcentury, instead of by more than 2 billion, as expected, it would be the equivalent of cutting as much as 29% of the emissions reductions needed by 2050 to keep the planet from tipping into a warmer, more dangerous zone. By the end of the century, it could cut fossil fuel pollution by 41%.

That's similar to some of the other large-scale emissions-cutting strategies, such as doubling the fuel efficiency of 2 billion cars from 30 miles per gallon to 60 or replacing coal power with a 700-fold increase in solar power.

Richard Somerville, a climate scientist at Scripps Institution of Oceanography, said he was impressed that researchers had tackled population growth, an often-taboo topic because of religious and cultural resistance.

“People are not aware of how fast the population has grown and how it’s a multiplier of consumption,” said Somerville, who was not involved in the study. “You don’t see policymakers taking about it in climate negotiations.”

Published Tuesday in the Proceedings of the National Academy of Sciences, the study offers a novel way to quantify how changes in human population influence the buildup of greenhouse gases in the atmosphere. Brian O’Neill, a scientist at the National Center for Atmospheric Research in Boulder, Colo., was the lead author.

Drawing on surveys from 34 countries — representing 61% of the world’s population — the analysis looks at how demographic changes affect economic growth and energy use and the resulting pollution.

Today’s population of 6.9 billion is expected to reach 9.1 billion by 2050, according to United Nations demographers. They suggest two alternative scenarios: a path of slower growth that would reach slightly less than 8 billion or a faster one that would reach nearly 10.5 billion.

But it’s not just population size that matters, the study found. It’s also where and how people live.

Growth in the United States has an outsized influence. An average U.S. resident emits four times as much carbon dioxide as a resident of China and 20 times as much as an African. The U.S. Census Bureau estimates that U.S. population of 310 million will swell to 439 million by midcentury, with most of the growth from immigrants and their children. More broadly, the scientists found the trend toward urbanization had a large effect on pollution levels. In developing countries, a typical farmer may or may not have electricity back home but generates more pollution after moving into a bustling city with modern amenities.

The most profound influence was urban migration’s indirect effect through economic growth. It’s a twist on the idea that a booming economy, like a rising tide, lifts all boats. In this case, economic growth lifts pollution levels higher too. “As the economy grows faster, it raises the income for everybody, and people are spending more money and consuming more and emitting more,” O’Neill said. As the population ages, the ranks of retirees swell, slowing economic growth, he said. The result: lower emissions.

When it comes to climate change, O’Neill said some people believe human population is the key, underlying problem. Others believe it’s inconsequential. “We find that the truth probably lies somewhere in between.”

-- Kenneth R. Weiss


Humanity's ever-bigger footprint

Tie your tubes and save the planet?

Photo: Children in a shantytown in Mumbai, India, watch television. Credit: European Pressphoto Agency

Comments () | Archives (15)

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It’s encouraging to see coverage of this report. It reminds me of a quote Edward C. Hartman used in his book, “The Population Fix,” from Dr. Albert Bartlett, physics professor at Colorado University: “Can you think of any problem on any scale, from microscopic to global, whose long-term solution is in any way aided, assisted or advanced by having larger populations at the local level, state level, nationally or globally? Can you think of anything that will get better if we crowd more people into our towns, cities, states, nations or world?”

It's not just literacy rates that are indicative of reproductive rates. More rigid fundamentalist religious belief also follows reproductive rates. The more religious the person the more likely he/she will reproduce too much. And I do mean too much. The fatalism inherent in many religions takes the burden of responsibility for children off the parent because "God will provide".

All these are factors; literacy, access to electricity, religion/superstitions, women's rights are all problems to be dealt with in solving the population problem. And it is very real. The 6.9 billion pound gorilla on the earth.

And to Mr Paul Taylor Examiner; do us a favor and don't reproduce. Your apparent allergy to facts and need for anger management can be cured.

If you haven't noticed humans our becoming resistant to antibiotics by design. Antibiotics our in our meat which will make us more resistant to the drug for the future. Their is a mass population reduction in the works and the swine flu was just a test run. The mass killing off of society should bring the population down to about a billion which is what the Earth can really sustain.

Kenneth Weiss has done a good job of drawing attention to human caused climate change. Human beings are a rapacious species. In the next decades there will be huge numbers, 2 billion, people moving into the middle class and they are all going to want energy for their life style. Yipe! I think one partial but crucial answer is girls' and women's education and access to reproductive health including family planning. Family planning is a great gift to the world. Yet 210 million women and their families lack access to this most basic contribution to health and welfare. This figure comes from the United Nations Population Fund which strives mightily to offer women the same reproductive health services (minus abortion) which we all take for granted. I am cofounder of 34 Million Friends of UNFPA. It's anamazing grassroots effort When the world takes care of women, women take care of the world.

Population is just one piece of the puzzle.

Some 40 years ago, Paul Erlich came up with the formula:

I = P * A * T

or total Impact on the environment is equal to Population times Affluence times Technology.

I think what Erlich called "affluence" is actually "access to energy." It isn't "literacy" that decreases population growth -- it isn't even womens' equality -- it's access to energy. When a woman doesn't have to walk five miles to fetch water because a pump brings it to her village, she doesn't have to breed a water-fetcher.

Problem is, cheap energy is going away. Dana Meadows (et. al.) noted in the Club of Rome report, "Limits to Growth," that population growth will begin to decline as we near peak energy availability, and then the birth rate goes up again. When you can't get diesel fuel to plough the back 40, you'll have to breed your labour force.

A lot of us are going to be employed growing our food again, Real Soon Now. Before the widespread use of fossil energy, there were fifteen families on the land for every one in the city. In the face of declining fossil energy, what makes us think we can maintain the current ratio of nearly 900 urban families living off the food-growing efforts of a single farming family?

So yea, let's do what we can to cut population -- assuming we can do ANYTHING, in the face of the primary support for reduced fecundity going away. But let's not forget the other terms in Erlich's equation, as well -- all three WILL be reduced in a painful manner, if we don't choose to voluntarily reduce them in the least painful manner we can manage.

soylent green is people! soylent green is people! oh wait that was was science fiction 40 years ago so is this story carbon dioxide is plant food

Even if you don't choose to believe in human-caused climate change, there are plenty of other reasons for us to limit our numbers: species extinction, fresh water supply, limited fertile soil/food supply, toxic accumulation, and a finite supply of many resources.

As for literacy vs. contraception, I don't think literacy without access to contraception will have a positive effect on reducing fertility rates.

It is amazing the lengths we will go to try to minimize or mitigate our impact on the planet, but God forbid we actually talk about making responsible family size decisions.

Dave Gardner
Producing the documentary
GrowthBusters: Hooked on Growth

As the author stated..."the truth probably lies somewhere in between". Evidently, the frothing at the mouth, radical, extremist posters below are so far from the middle and a moderate point of view that they wouldn't know one if it slapped them in the face. You can thank environmental activists for our National Parks, for clean air and clean water standards without which they would be drinking and sucking on filth and much more than I care to enumerate. Remember when Los Angeles had smog that was so much worse than it is today? I'm one of those activists who helped force clean air standards in Southern California. Hey morons, you're welcome.

Good to see this issue being taken seriously. Whenever I hear someone talking about technological fixes, I think how simple it would be if we could just slow and stop population growth. If we lived with 3 billion people on the planet, or 1, imagine how much less the issues of the day would plague us - species loss, pollution, climate change, traffic, housing shortages, water and food scarcity. I believe the group, Population Connection, formerly ZPG, has a good handle on this issue and support their work.

Also, the Population Media Institute is doing great work in teaching people around the world about family planning.

The first decade of the 21st Century may be seen as the decade in which environmentalism peaked, and then failed from its own hubris and corruption. It has taken about a decade in a deluge of environmental proselytizing, marketing, hysterics and gratuitous lies to expose the greed and fear mongering of a movement that exists now as just another political special interest. Their shameful trade in scary eco-scenarios now falls on deaf ears in the public mind. Except for those for whom environmentalism is a practiced religion or commercial enterprise, eco-themes and incentives have been largely exhausted, and even caricatured in our popular culture.

Radical environmentalism can also be seen as a disorder, where the sanctimonious enviro-activist’s obsessive insistence that you should change your lifestyle toward eco-purity begins to impair their personal and professional relationships. The enduring negative impact of environmental activism is the politicization of your way of life.

As with other obsession and addiction disorders, therapies and counseling in the form of “12-Step” clinical programs may be helpful in moderating radical enviro-behaviors. Here are 12 behavioral modifications that may be productive steps in recovery from ,or avoidance of, radical environmentalism:
1. Avoid the tactic of fear mongering campaigns;
2. Stop giving to taxpayer-subsidized, nonprofit eco-groups and think tanks;
3. Critically view progressive (a.k.a, liberal) enviro operatives in the media;
4. Accept that there are legitimate skeptics in debates over scary eco-scenarios;
5. Stop substituting personal compassion where science is required in environmental issues;
6. Stop assuming that another costly government regulation will fix every environmental problem;
7. Resist socialist initiatives claiming environmental justice and social justice;
8. Ignore the eco-claimed moral equivalence between human life and wildlife;
9. Reduce your associations with the union, bureaucratic, leftist and eco-terrorist political enablers of radical environmentalism;
10. Insist upon economic cost-benefit analyses in all environmental regulations;
11. Don’t accept that any government regulation can dictate any miraculous scientific breakthrough;
12. Accept that 40 years of local, state and federal environmental regulations have embedded cost increases in all of our goods, services and activities. And, understand that most of our real environmental problems are solved, or are under active management.

If you look at the correlation between reproductive rates and literacy rates, there is a strong inverse correlation. The lower the literacy, the higher the reproductive rates. And vise versa. The key to reducing population is literacy, not abortions or the pill or condoms, it’s literacy. But literacy is expensive and takes generations. On the other hand, abortions, condoms and the pill are cheap and fast, but they also keep the population illiterate and stupid (just the way the left want them). I vote for literacy.

Let me knock down this strwaman down. THERE IS NO HUMAN CAUSED GLOBAL WARMING/GLOBAL CLIMATE CHANGE/ GLOBAL CLIMATE DISRUPTION. It's a hoax folks. Therefor there is no need for a 1930s style eugenics program like Obamacare.

If the author is so concerned he should organize a mass eco suicide party. Global warming will decline when there is less of their b.s. heating up the atmosphere.

Of course we should get rid of people. Isn't that the aim of any fascist movement worth it's salt? Here we are... there hasn't been any warming in 10 years despite an increase in CO2. The Climate Change theory is turning into faerie dust before our eyes with the whole climategate mess. Harold Lewis is Emeritus Professor of Physics at the University of California, Santa Barbara... for 67 years, he held a leadership position, and he just resigned, because: "Global warming is the greatest and most successful pseudoscientific fraud I have seen in my long life."

Now would be the perfect time to sacrifice actual human beings for this green religion. Go for broke, that's what I say! It's what you guys have always wanted anyway, right? What is it about the Left, that they always go down the road of mass exterminations? Whether it be socialism, communism, or progressivism... eventually they get the idea that "other people" are "in the way", and they start calculating the amount of carbon they could save if they were "done away with". It's sick.

Of course, population growth is the problem.

We need to stop giving tax deductions for more than 2 (replacement) children.

We need to start letting diseases everywhere, but particularly in overpopulated areas that are already experiencing famine and genocode based on overpopulation, take their natural course.

It might Bono and Bill Gates feel good to continually interfere with the natural course of events, but we need to stop playing god if we want any hope of saving any of the planet for human habitation. We are literally interfering with the natural evolution of the human species by defying the survival of the fittest and destroying the planet at the same time.

The cultures of the different peoples of the earth have always evolved at different rates. We have forced these people into accepting our westernized standards as their own. It has been creating havoc since the colonial era beginning in the 1400s. It accelerated at the end of teh colonial era.

Doesn't anyone remember The Population Bomb? I gave at book report on in to my pol sci class in 1970. The time frame was off, but we are trying as hard as we can to destroy ourselves. When People magazine was new, there was a story about the man in charge of contraception in someplace like Singapore or Indonesia. His slogan to reduce an out of control populace was: "too many children make you poor". So true. Too bad we have lost the common sense to know that.


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