Just the facts
Population Reference Bureau - In mid-2008, world population stood at 6.7 billion, up from 6.0 billion in 1999. The next milestone, 7 billion, will likely be passed in 2011 or 2012.
During the 20th century, nearly 90 percent of population growth took place in countries classified as less developed by the United Nations - all countries in Africa, Asia (except Japan), Latin America and the Caribbean, and Oceania (except Australia and New Zealand). This remarkable development resulted from an unprecedented decline in death rates in LDCs brought about by the spread of public health measures, health care, and disease prevention, particularly after the end of World War II in 1945. These improvements evolved over centuries in the more developed countries, but the LDCs were able to benefit from them virtually overnight.
The imbalance in population growth seen over the last century will only intensify in the years to come.
Between 2008 and 2050, virtually all population growth will take place in the LDCs. Overall, the small amount of population growth projected for MDCs will be largely accounted for by the United States and Canada. But most of that growth will likely be due to immigration from LDCs. While the LDCs are projected to increase from 5.5 billion in 2008 to 8.1 billion in 2050, the MDCs are projected to grow from 1.2 billion to just 1.3 billion.
During 2008, about 139 million babies will have been born worldwide and 57 million people will likely die, so that global population will increase by 82 million. Overall, women would average about 2.6 children at the pace of childbearing in 2008, but that figure varies substantially from region to region and country to country. In MDCs, women average 1.6 children, a number insufficient to forestall eventual population decline. Some European countries and Japan are already experiencing more deaths annually than births. In the LDCs, excluding the large statistical effect of China, women average 3.2 children, twice that of the wealthier countries.
In the 50 UN-defined least developed countries, the number is even higher-4.7 children per woman.
For the first time, the world population is evenly divided between urban and rural areas. By 2050, urban residents are likely to make up 70 percent of the world's population. . .
More than half of urban growth occurs in cities with populations of 500,000 citizens or fewer.
Megacities-urban areas with populations of 10 million or more-only account for 8 percent of the urban population.
Virtually all of the urban population growth will be happening in less developed regions. By 2050, North America's population may be 90 percent urban.
Urban populations consume
more food, durable goods, and energy than their rural counterparts.
Paul R. Ehrlich and Anne H. Ehrlich, E360 - In the last several centuries we've increasingly been using our relatively newly acquired power, especially our culturally evolved technologies, to deplete the natural capital of Earth - in particular its deep, rich agricultural soils, its groundwater stored during ice ages, and its biodiversity - as if there were no tomorrow.
The point, all too often ignored, is that this trend is being driven in large part by a combination of population growth and increasing per capita consumption, and it cannot be long continued without risking a collapse of our now-global civilization. Too many people - and especially too many politicians and business executives - are under the delusion that such a disastrous end to the modern human enterprise can be avoided by technological fixes that will allow the population and the economy to grow forever. But if we fail to bring population growth and over-consumption under control - the number of people on Earth is expected to grow from 6.5 billion today to 9 billion by the second half of the 21st century - then we will inhabit a planet where life becomes increasingly untenable because of two looming crises: global heating, and the degradation of the natural systems on which we all depend. . .
Two billion people, all else being equal, put more greenhouse gases into the atmosphere than one billion people. Two billion rich people disrupt the climate more than two billion poor people. Three hundred million Americans consume more petroleum than 1.3 billion Chinese. And driving an SUV is using a far more environmentally malign transportation technology than riding mass transit.
The technological dimensions of our predicament - such as the need for alternatives to fossil fuel energy - are frequently discussed if too little acted upon. Judging from media reports and the statements of politicians, environmental problems, to the degree they are recognized, can be solved by minor changes in technologies and recycling. Switching to ultra-light, fuel-efficient cars will obviously give some short-term advantage, but as population and consumption grow, they will pour still more carbon dioxide (and vaporized rubber) into the atmosphere and require more natural areas to be buried under concrete. More recycling will help, but many of our society's potentially most dangerous effluents (such as hormone-mimicking chemicals) cannot practically be recycled. There is no technological change we can make that will permit growth in either human numbers or material affluence to continue to expand. In the face of this, the neglect of the intertwined issues of population and consumption is stunning.
Many past human societies have collapsed under the weight of overpopulation and environmental neglect, but today the civilization in peril is global. The population factor in what appears to be a looming catastrophe is even greater than most people suppose. Each person added today to the population on average causes more damage to humanity's critical life-support systems than did the previous addition - everything else being equal. The reason is simple: Homo sapiens became the dominant animal by being smart. Farmers didn't settle first on poor soils where water was scarce, but rather in rich river valleys. That's where most cities developed, where rich soils are now being paved over for roads and suburbs, and where water supplies are being polluted or overexploited.
As a result, to support additional people it is necessary to move to ever poorer lands, drill wells deeper, or tap increasingly remote sources to obtain water - and then spend more energy to transport that water ever greater distances to farm fields, homes, and factories. Our distant ancestors could pick up nearly pure copper on Earth's surface when they started to use metals; now people must use vast amounts of energy to mine and smelt gigantic amounts of copper ore of ever poorer quality, some in concentrations of less than one percent. The same can be said for other important metals. And petroleum can no longer be found easily on or near the surface, but must be gleaned from wells drilled a mile or more deep, often in inaccessible localities, such as under continental shelves beneath the sea. All of the paving, drilling, fertilizer manufacturing, pumping, smelting, and transporting needed to provide for the consumption of burgeoning numbers of people produces greenhouse gases and thus tightens the connection between population and climate disruption.
So why is the topic of overpopulation so generally ignored? There are some obvious reasons. Attempts by governments to limit their nation's population growth are anathema to those on the right who believe the only role for governments in the bedroom is to force women to take unwanted babies to term. Those on the left fear, with some legitimacy, that population control could turn racist or discriminatory in other ways - for example, attempting to reduce the numbers of minorities or the poor. Many fear the specter of more of "them" compared to "us," and all of us fear loss of liberty and economic decline (since population growth is often claimed necessary for economic health). And there are religious leaders who still try to promote over-reproduction by their flocks, though in much of the world their efforts are largely futile (Catholic countries in Europe tend to be low-birthrate leaders, for example).
But much of the responsibility must go to ignorance, which leads mainstream media, even newspapers like The New York Times, to maintain a pro-natalist stance. For example, the Times had an article on June 29 about a "baby bust" in industrialized countries in which the United States (still growing) was noted as a "sparkling exception." Beyond the media, great foundations have turned their "population programs" away from encouraging low fertility rates and toward topics like "changing sexual mores" - avoiding discussion of the contribution demographics is making to a possible collapse of civilization.
Some leading economists are starting to tackle the issue of over-consumption, but the problems and its cures are tough to analyze."
Consumption is still viewed as an unalloyed good by many economists, along with business leaders and politicians, who tend to see jacking up consumption as a cure-all for economic ills. Too much unemployment? Encourage people to buy an SUV or a new refrigerator. Perpetual growth is the creed of the cancer cell, but third-rate economists can't think of anything else. Some leading economists are starting to tackle the issue of overconsumption, but the problem and its cures are tough to analyze. Scientists have yet to develop consumption condoms or morning-after-shopping-spree pills.
And, of course, there are the vexing problems of consumption of people in poor countries. On one hand, a billion or more people have problems of under-consumption. Unless their basic needs are met, they are unlikely to be able to make important contributions to attaining sustainability. On the other hand, there is also the issue of the "new consumers" in developing economies such as China and India, where the wealth of a sizable minority is permitting them to acquire the consumption habits (e.g., eating a lot of meat and driving automobiles) of the rich nations. Consumption regulation is a lot more complex than population regulation, and it is much more difficult to find humane and equitable solutions to the problem.
The dominant animal is wasting its brilliance and its wonderful achievements; civilization's fate is being determined by decision makers who determinedly look the other way in favor of immediate comfort and profit. Thousands of scientists recently participated in a Millennium Ecosystem Assessment that outlined our current environmental dilemma, but the report's dire message made very little impact. Absent attention to that message, the fates of Easter Island, the Classic Maya civilization, and Nineveh - all of which collapsed following environmental degradation - await us all. . .
DAILY GREEN - Sub-Saharan Africa is headed for a "population emergency" according to a new French analysis of demographic trends. The population of the continent south of the Sahara, decimated by the slave trade and colonization, stood at 100 million in 1900, according to the study by Centre Population et Developpement. It had grown more than seven-fold to 770 million by 2005. By 2050, it will grow by as much as 2.6 times above that level, to 2 billion. The population of the entire world today is 6.6 billion.
In 1960, one African city had 1 million residents. Now, 40 do, and the rural exodus is continuing at such a pace that already strained cities are struggling to provide services, like health care, and infrastructure, like sewage treatment, enough to support the population growth.
Only six nations had economic growth above 7% - the rate believed needed to support population growth of this magnitude.
POPULATION GROWTH: THE CRISIS THAT DARES NOT SAY ITS NAME
ELECTRIC POLITICS recently featured a low keyed discussion of an extremely hot button subject: population growth. The guest was Al Bartlett, professor of physics emeritus at the University of Colorado, who has been working on sustainability issues for decades. It is an issue that we raise from time to time, get a few letters accusing us of being racists or eugenicists and then move on to easier topics. But if what people like Bartlett are saying is true? Then much of we believe about economics and the environment may eventually seem extraordinarily short-sighted or just plain wrong. Nothing we do about the environment, for example, will matter if the world population continues to grow because that presumes an ever larger depletion of the natural resources of the earth. Interestingly, we avoid the issue even more than we did 35 years ago when a national commission issued some important suggestions on dealing with the matter. Some insights follow.
AL BARTLETT PODCAST INTERVIEW
1972 ROCKEFELLER COMMISSION REPORT ON U. S. POPULATION - In March of 1970, President Nixon signed a bill establishing the Commission on Population Growth and the American Future, known as the Rockefeller Commission, for it chairman, John D. Rockefeller 3rd. In 1972, the Commission released, its recommendations, including:
- In view of the important role that education can play in developing an understanding of the causes and consequences of population growth and distribution, the Commission recommends enactment of a Population Education Act to assist school systems in establishing well-planned population education programs so that present and future generations will be better prepared to meet the challenges arising from population change.
- Recognizing the importance of human sexuality, the Commission recommends that sex education be available to all, and that it be presented in a responsible manner through community organizations, the media, and especially the schools.
- The Commission recommends that the Congress and the states approve the proposed Equal Rights Amendment and that federal, state, and local governments undertake positive programs to ensure freedom from discrimination based on sex.
- The Commission recommends that (1) states eliminate existing legal inhibitions and restrictions on access to contraceptive information, procedures, and supplies; and (2) states develop statutes affirming the desirability that all persons have ready and practicable access to contraceptive information, procedures, and supplies.
- The Commission recommends that states adopt affirmative legislation which will permit minors to receive contraceptive and prophylactic information and services in appropriate settings sensitive to their needs and concerns.
- In order to permit freedom of choice, the Commission recommends that all administration restrictions on access to voluntary contraceptive sterilization be eliminated so that the decision be made solely by physician and patient.
- With the admonition that abortion not be considered a primary means of fertility control, the Commission recommends that present state laws restricting abortion be liberalized along the lines of the New York statute, such abortion to be performed on request by duly licensed physicians under conditions of medical safety.
- The Commission recommends that this nation give the highest priority to research on reproductive biology and to the search for improved methods by which individuals can control their own fertility.
- Recognizing that our population cannot grow indefinitely, and appreciating the advantages of moving now toward the stabilization of population, the Commission recommends that the nation welcome and plan for a stabilized population.
- The Commission recommends the creation of an Office of Population Growth and Distribution within the Executive Office of the President.
- The Commission recommends the immediate addition of personnel with demographic expertise to the staffs of the Council of Economic Advisers, the Domestic Council, the Council on Environmental Quality, and the Office of Science and Technology.
- In order to provide legislative oversight of population issues, the Commission recommends that Congress assign to a joint committee responsibility for specific review of this area.
CHRIS RAPLEY - By avoiding a fraction of the projected population increase, the emissions savings could be significant and would be at a cost, based on UN experience of reproductive health programs, that would be as little as one-thousandth of the technological fixes. The reality is that while the footprint of each individual cannot be reduced to zero, the absence of an individual does do so.
ROGER MILLER, SUNY POTSDAM - Loss of biodiversity and natural habitats, depletion of the aquifers, air and water pollution, our eventual inability to grow sufficient food or to generate sufficient energy are all problems cause by a large and rapidly growing human population. Not only is it the primary cause of these problems, but no solution exists to solving these problems as long as the population continues to grow.
Populations cannot grow indefinitely in a finite environment. The United States population is currently growing at a 1% annual rate, and the worldwide population is growing at a 1.3% rate per year; rates that are fairly low compared to historic levels. If the world's population continued to grow at 1.3% for approximately 800 years, there would be 1 person for every 1 square meter of the earth's surface, and if it could continue growing at this rate for approximately 2200 years, the mass of humanity would equal the mass of the earth. Clearly before this happens we will reach a zero population growth level if we are lucky, and if we are not lucky we will have a period of enormous decrease in the population, whether by famine, disease or some other natural or man-made catastrophe.
JIM LYDECKER, GROWTH IS MADNESS - The biggest crisis is overpopulation. Every problem, be it environmental, economic, social or political, is directly or indirectly connected to the 6.8-billion-pound gorilla in the room. We have known this for years but it is one of the issues no one, conservative or liberal, will touch. Instead, the official policy is one of ignorance allowing the human species to breed itself toward a massive die-off. . .
In just a little more than 130 years, humans have run through more than half the world's reserves of oil and natural gas. Since population growth is contingent on a readily available supply of cheap oil, collapse is inevitable. The slippery slide down the slope of peak oil will be quicker than the trip up.
Without cheap oil and natural gas, the green revolution and the ability to feed all us billions will be history. Few industries will be affected as great as agriculture. Two that will be are those medical and pharmaceutical.
Thus, a future die-off of biblical proportions will be primarily due to starvation and disease. Throw in mass migrations and social strife and, boy, do we have problems.
BRIAN CZECH AND HERMAN E. DALY, WILDLIFE SOCIETY BULLETIN 2004 - A steady state economy with long human life spans entails low birth and death rates. In our opinion this is preferable, within reason, to a steady state economy with short life spans, high birth rates, and high death rates. The same concept applies to capital and durable goods such as automobiles. We opine that a relatively slow flow of high-quality, long-lasting goods is preferable to a fast flow of low-quality, short-lived goods.
Nothing about a steady state economy precludes economic development, where development is defined as a qualitative process. Various sectors may come and go in a steady state economy. For example, organic farms may supplant factory farms, the proportion of bicycles to Humvees may increase, and professional soccer may attract more fans while NASCAR attracts fewer. As long as the physical size of the economy remains constant in the long run, a developing economy is a steady state economy.
Nor would any type of cultural stagnation result from a steady state economy.
John Stuart Mill, one of the greatest economists and political philosophers in history, emphasized that an economy in which physical growth was no longer the goal would be more conducive to political, ethical, and spiritual improvements
A steady state economy means a constant rate of employment. . . Economic development continues in a steady state economy so that in the extractive sector, oilfield roughnecks may decrease in number while wind-power facility attendants may increase. In the arts, guitar playing may wax while flute playing wanes. In the sciences, industrial chemists may be replaced by wildlife ecologists. . .
In a steady state economy, the average amount of money in real dollars earned by workers from the current generation to the next remains constant.
"Real dollars" means that inflation has been accounted for. Because income reflects the use of natural resources, stabilized income reflects a stabilized "ecological footprint," which is the area of land required to support a human being . . .
If the steady state economy is established at a relatively low population level, the potential exists for each worker, and his replacement in the next generation, to earn a high income. This scenario is similar to that of a low-density deer population with plenty of forage per deer. If, on the other hand, the steady state economy is established at a high population level, less income is available for the average worker, as in a high-density deer population with little forage per deer.
We think it important that a steady state economy be established at a relatively low population level. This scenario is conducive to incomes high enough to allow retirement savings and social secu rity (in the generic sense), making the economy more politically acceptable and therefore more stable. If the steady state economy is established with-in ecological carrying capacity, each new generation may expect its workers to accumulate retire- ment savings of the same magnitude as the previous generation. So we think it important to establish a steady state economy as soon as possible. As the population grows, it becomes less likely the steady state economy may be established whereby incomes are high enough to support reasonable periods of retirement.
Won't the stock market crash if a steady state economy is established? . . . Many people view the stock market as predicated on economic growth, so they wonder if a stock market could even exist in a steady state economy. It certainly could and probably would. In a steady state economy, firms still need to invest in capital--namely, at the same rate at which capital depreciates.
Publicly traded stocks provide the social benefit of liquidity to investors and offer an efficient mechanism for the acquisition of investment capital.
Stock markets tend to expand and contract in concert (though often with lags) with gross domestic product, the dollar value of newly produced, final goods and services. There are winners and losers in bullish and bearish markets, though the winners tend to be more prominent in the for- mer. The stock market in a steady state economy of stable GDP would be neither bullish nor bearish for extended periods. It, too, would have winners and losers, with perennial losers becoming insolvent and being replaced by more competent firms. But in a steady state economy the stock market would be less of a casino than in the growth economy.
Economic growth, on the other hand, is bound to cause an extensive and extended stock market crash because demands for capital eventually will exceed the productive capacity of the earth.
Therefore, advocating a steady state economy is appropriate not only for purposes of wildlife conservation but also because it would reduce the volatility of the stock market.
There are, of course, alternatives to the stock market for purposes of financing capital investment. For example, capital may be financed by private banks, cooperatives, and governments. In fact, all of these institutions are active financiers throughout the world. The relative prominence of each in a given nation helps to describe that nation's history, ideology, and "political economy," which brings us to our next question--a very big one.
Doesn't a steady state economy require a socialist government? More generally put, what kind of government is most conducive to a steady state economy? Might it be, for example, a capitalist democracy, a communist state or a dictatorship? In theory, each is capable of producing or coexisting with a steady state economy, but we do not think any of these is particularly conducive. Each has exhibited far more concern with GDP growth than with other important endeavors, such as poverty alleviation and, of course, wildlife conservation.
We think the form of government most conducive to a steady state economy, in the context of twenty-first-century nation states, is a constitutional democracy somewhat more socialized than the current American version. "Socialist democracies," as the term is used in political science, already exist in many nations, most notably such European nations as Sweden, Switzerland and England.
Economists more frequently call them "mixed economies." These are democratically operated governments in which the state plays a more prominent role in the economy than the American government plays in its economy
DAVID HOULE, SCIENTIFIC BLOGGING - The impact that humanity is having on climate change is directly related to the fact that there are so many of us. Add on top of our shear numbers the fact that we treat the planet harshly and it is clear why we are moving toward a global crisis.
Consider some facts about the growth of human population. Humans have been on the planet for hundreds of thousands of years. It took until 1804 for our numbers to reach 1 billion. It took another 123 years to reach 2 billion in 1927. It only took another 33 years for us to reach 3 billion in 1960 and 14 years to reach 4 billion in 1974. That means that if you are older that 40 the world's population has doubled in your lifetime. There are now 6.6 times more of us now than 200 hundred years ago. It is also during these 200 hundred years that the Industrial Revolution occurred, bringing with it the use of fossil fuels for powering our societies and economies.
WILLIAM JOHNSON, POPULATION INSTITUTE - While a great deal of attention has been paid to reducing emissions responsible for global warming, there has been far less focus on the role of population growth in climate change. The world's population is projected to increase 40% by 2050. Thus, a 40% decrease in per capita carbon emissions in the industrialized world would be canceled out by global population growth and higher per capita emissions in the developing world.
As population increases, the challenge of slowing climate change and the risk of catastrophic consequences rise inexorably. The world is already experiencing increased sea levels, floods, violent storms, droughts, heat waves, disease transmission, and environmental refugees as a result of climate change. The World Health Organization estimates the percentage of the world's population affected by weather disasters has doubled in the past 25 years, and the coming years may be worse. . .
Demurral and denial may be more convenient and politically acceptable than the truth, but we need to face reality. While nations struggle to find the appropriate technical, economic and political framework for sharing the burden of reducing carbon emissions, there is an urgent need to open a second front in the battle against climate change by reducing population growth.
Although the first challenge is quite difficult, the second is relatively easy. We know that family planning works, and when women have free access to information and services to practice family planning they have smaller families. A Baltimore Sun editorial by John Seager put it best: "If we had zero population growth, part of the global warming problem would, well, melt away." . . .
ANDREW WOODCOCK, INDEPENDENT, 2006 - Environmental problems such as global warming can be tackled only if the international community addresses the problem of population growth, a leading scientist warned. Professor Chris Rapley, the director of the British Antarctic Survey, said the 76 million annual increase in the world's population threatens "the welfare and quality of life of future generations".
But he said population growth was the "Cinderella" issue of the environmental debate, because its implications are so controversial that nobody dares to raise it.
Scientific analysis suggests that the Earth can sustain around 2-3 billion people at a good standard of living over the long term, wrote Prof. Rapley in an article for the BBC News website. But the current global population of 6.5 billion - expected to rise to 8 billion by the middle of the century - means mankind is imposing an ever greater "footprint" on the planet. . .
OPTIMUM POPULATION - Each new UK citizen less means a lifetime carbon dioxide saving of nearly 750 tons, a climate impact equivalent to 620 return flights between London and New York*, the Optimum Population Trust says in a new report. . . The climate cost of each new Briton over their lifetime at roughly L30,000. The lifetime emission costs of the extra 10 million people projected for the UK by 2074 would therefore be over L300 billion. A 35-pence condom, which could avert that L30,000 cost from a single use, thus represents a "spectacular" potential return on investment - around nine million per cent.
The report adds: "The most effective personal climate change strategy is limiting the number of children one has.". . .
A Population-Based Climate Strategy, the OPT's latest research briefing, says human population growth is widely acknowledged as one of the main causes of climate change yet politicians and environmentalists rarely discuss it for fear of causing offence. The result is that a "de facto taboo" exists, throughout civil society and government.
One consequence is that "couples making decisions about family size do so in the belief that it is a matter for them and their personal preferences alone: the public debate and awareness that might have encouraged them to think about the implications of their choices for their fellow citizens, the climate and the wider environment have been missing."
Valerie Stevens, co-chair of the OPT, said: "We appreciate that asking people to have fewer children is not going to make us popular in some quarters. Equally, expressing concern about the environmental impacts of mass migration, which currently accounts for the bulk of population growth in the UK and will have a major effect on Britain's carbon emissions, is a quick route to being labeled racist. But these are hugely important issues and the unfortunate fact is that both politicians and the environmental movement are in denial about them. It's high time we started discussing them like adults and confronting the real challenges of climate change."
EARTH DAY NET - International cooperation on population has gone a long way to slow the growth of world population. But fertility rates in many countries remain high. A quarter century of research shows that those rates decline when voluntary family planning is universally available and educational opportunities for girls and economic opportunities for women increase. Indeed, long-range strategies to address the threat of climate change are unlikely to succeed without paying careful attention to demographic trends.
Scientists across the globe agree that the influence of humans and their activities on the earth's atmosphere and climate is an established fact. If population growth and climate change are closely linked, then they should be integrated into policy and challenged together. Long-term strategies to reduce global greenhouse gas emissions in an equitable manner will need to account for the current broad differences among nations in per capita emissions. Effective, voluntary family planning plus improved educational and economic opportunities for girls and women are a central part of good population policy as well as a key to greenhouse gas reduction.
LESTER BROWN, EARTH POLICY - We know from earlier civilizations that the lead indicators of economic decline were environmental, not economic. The trees went first, then the soil, and finally the civilization itself. To archeologists, the sequence is all too familiar.
Our situation today is far more challenging because in addition to shrinking forests and eroding soils, we must deal with falling water tables, more frequent crop-withering heat waves, collapsing fisheries, expanding deserts, deteriorating rangelands, dying coral reefs, melting glaciers, rising seas, more-powerful storms, disappearing species, and, soon, shrinking oil supplies. Although these ecologically destructive trends have been evident for some time, and some have been reversed at the national level, not one has been reversed at the global level.
The bottom line is that the world is in what ecologists call an "overshoot-and-collapse" mode. Demand has exceeded the sustainable yield of natural systems at the local level countless times in the past. Now, for the first time, it is doing so at the global level. Forests are shrinking for the world as a whole. Fishery collapses are widespread. Grasslands are deteriorating on every continent. Water tables are falling in many countries. . .
In 2002, a team of scientists led by Mathis Wackernagel, who now heads the Global Footprint Network, concluded that humanity's collective demands first surpassed the earth's regenerative capacity around 1980. Their study, published by the U.S. National Academy of Sciences, estimated that global demands in 1999 exceeded that capacity by 20 percent. The gap, growing by 1 percent or so a year, is now much wider. We are meeting current demands by consuming the earth's natural assets, setting the stage for decline and collapse.
In a rather ingenious approach to calculating the human physical presence on the planet, Paul MacCready, the founder and Chairman of Aerovironment and designer of the first solar-powered aircraft, has calculated the weight of all vertebrates on the land and in the air. He notes that when agriculture began, humans, their livestock, and pets together accounted for less than 0.1 percent of the total. Today, he estimates, this group accounts for 98 percent of the earth's total vertebrate biomass, leaving only 2 percent for the wild portion, the latter including all the deer, wildebeests, elephants, great cats, birds, small mammals, and so forth.
Ecologists are intimately familiar with the overshoot-and-collapse phenomenon. One of their favorite examples began in 1944, when the Coast Guard introduced 29 reindeer on remote St. Matthew Island in the Bering Sea to serve as the backup food source for the 19 men operating a station there. After World War II ended a year later, the base was closed and the men left the island. When U.S. Fish and Wildlife Service biologist David Kline visited St. Matthew in 1957, he discovered a thriving population of 1,350 reindeer feeding on the thick mat of lichen that covered the 332-square-kilometer (128-square-mile) island. In the absence of any predators, the population was exploding. By 1963, it had reached 6,000. He returned to St. Matthew in 1966 and discovered an island strewn with reindeer skeletons and not much lichen. Only 42 of the reindeer survived: 41 females and 1 not entirely healthy male. There were no fawns. By 1980 or so, the remaining reindeer had died off.
Like the deer on St. Matthew Island, we too are over-consuming our natural resources. Overshoot leads sometimes to decline and sometimes to a complete collapse. It is not always clear which it will be. In the former, a remnant of the population or economic activity survives in a resource-depleted environment. For example, as the environmental resource base of Easter Island in the South Pacific deteriorated, its population declined from a peak of 20,000 several centuries ago to today's population of fewer than 4,000. In contrast, the 500-year-old Norse settlement in Greenland collapsed during the 1400s, disappearing entirely in the face of environmental adversity. . .
You do not need to be an ecologist to see that if recent environmental trends continue, the global economy eventually will come crashing down. It is not knowledge that we lack. At issue is whether national governments can stabilize population and restructure the economy before time runs out.
CARL SAGAN ON POPULATION GROWTH
There is a well-documented correlation between poverty and high birthrates. In little countries and big countries, capitalist countries and communist countries, Catholic countries and Moslem countries, Western countries and Eastern countries-in almost all these cases, exponential population growth slows down or stops when grinding poverty disappears. This is called demographic transition. It is in the urgent long-term interest of the human species that every place on Earth achieves this demographic transition. This is why helping other countries become self-sufficient is not only elementary human decency, but is also in the interest of those richer nations able to help. One of the central issues in the world population crisis is poverty.
The exceptions to the demographic transition are interesting. Some nations with high per capita incomes still have high birthrates. But in them, contraceptives are sparsely available, and/or women lack any effective political power. It is not hard to understand the connection.
At present there are about 6 billion humans. In 40 years, if the doubling time stays constant, there will be 12 billion; in 80 years, 24 billion; in 120 years, 48 billion. ... But few believe the Earth can support so many people. Because of the power of this exponential increase, dealing with global poverty now will be much cheaper and much more humane, it seems, than whatever solutions will be available to us many decades hence. Our job is to bring about a worldwide demographic transition and flatten out that exponential curve-by eliminating grinding poverty, making safe and effective birth control methods widely available, and extending real political power (executive, legislative, judicial, military, and in institutions influencing public opinion) to women. If we fail, some other process, less under out control, will do it for us."
-Carl Sagan, Billions & Billions: Thoughts on Life and Death at the Brink of the Millennium (1998, Ballantine Books)