World  governments, the public, and the UN now recognize that the human population number matters in achieving ecological sustainability for human communities.

For forty years, since the first United Nations environment meeting in Stockholm in 1972, environmentalists have debated whether we should include human population growth among the urgent challenges of  human consumption, industrial toxins, species loss, global warming, and so forth.

This debate appears to be resolved. Clearly, human population figures have an impact on the health of natural ecosystems. Virtually every nation in the world seeks more commodities for its citizens, and a growing population multiplies the effect of this growing per-capita resource consumption. We could make all the right moves regarding energy systems, transportation, and recycling, and still overshoot Earth’s capacity with unsustainable numbers of humans. It is a good sign that the United Nations now recognizes this.

UN special session on population

Next year, in September 2014, the United Nations will convene a special session on human population. The U.N. General Assembly finally intends to implement a population stabilization plan devised  twenty years ago at the U.N. population conference in Cairo. The original strategy, adopted by 180 nations, cited women’s rights, birth control, and economic development as keys to stabilizing population growth. This strategy remains valid, but is useless if not implemented with meaningful targets and actions. It may also prove useless if we do not re-define “economic development” to focus on better lives for the world’s poor, less wasteful consumption among the rich, and less concentration of wealth among the super-rich.

Since the Cairo conference, the world's population has grown from 5.7 billion to 7 billion people. We add about 75 million people each year – the equivalent of five cities the size of Beijing each year – but we fail to match this growth with new infrastructure, shelter, food, water, or health care. Adding more people simply puts more strain on Earth’s limited and dwindling resources. As we add more people, we lose some 16 million hectares of forest each year, gain 6 million hectares of desert, lose 26-billion tons of topsoil, deplete aquifers, and drain rivers. These trends are not sustainable.

The additional humans are crowded into existing cities and depleted countryside. About ten million people starve to death each year, over a billion people go hungry, and some 2 billion have no access to clean fresh water.

Lip service or real action?

The danger with UN meetings – as we witnessed with climate conferences –  is that no substantive action will follow. Kenya lead the movement for a UN population meeting, but Kenya's deputy U.N. ambassador Koki Muli warned that there will be no final document from the 2014 population session. The assembly may dodge the real changes that need to occur, choosing to avoid controversial issues such as universal women’s rights, girl’s education, abortion rights, and access to contraception.

Historical evidence shows that wherever women have rights over their own reproduction and where families have access to birth control, the fertility rate declines. Growth advocates claim that industrial development leads to lower population growth, but that is not always the case. Prior to 1964, population and GDP grow together. Since then, in Europe, fertility rates have dropped, but not in the US or Saudi Arabia where cultural resistance undermines family planning. However, in the 1970s, fertility rates fell in Spain and Italy, not because of increased wealth, but rather following the advent of women’s rights and available contraception. In Columbia, fertility rates dropped from 6 to 3.5 children per family in 15 years after contraception was made widely available.

The U.N. is correct to focus on these measures, but to be successful, the U.N. must be willing to confront cultural resistance with education. The Cairo conference recognized the need for comprehensive population policies that include family planning, gender equality, and sex education for both young women and men. However, they also noted that such policies will conflict with cultural habits. The Cairo conference recognized that practices such as abortion should be treated as a public health issue to ensure safe motherhood.

The U.N. Population Fund's executive director, Babatunde Osotimehin, believes the UN has to work with individual communities to reverse out-dated cultural practices such as contraception bans and female genital mutilation.  That organization has been working with UNICEF, the UN’s children fund, to encourage communities to stop the practice. In 2012 they met directly with 1,800 communities to overcome “major obstacles related to culture,” according to Osotimehin. They have worked to educate communities in family planning and contraception, which Osotimehin calls “the most important intervention you can give to liberate a women’s energy and life.” Finally, according to Osotimehin, “the world is listening.” 

Change in attitudes

With present practices, the UN estimates we are on pace for 10 billion people by 2050, and possibly 12 to 14 billion by 2100. That would mean twice as many humans in a world even more depleted of resources. Since we have not been able to feed or supply basic living standards for 7 billion, these figures appear frightening. However, attitudes are beginning to change.

In the US, the Center for Biological Diversity conducted a Public Poll a found that 60 percent of Americans now equate human population growth to wildlife extinctions; 57 percent understand the link to climate change. These represent marked changes from even a decade ago.

Real world environmental crises are driving these changes in attitude. In the US, for example, the nation is on track to lose 15 million hectares (36 million acres) of forest to urban sprawl by 2050. In Florida, due to over-pumping of water, salt water is now intruding into the primary aquifer, which supplies water for 19 million people. 

Water shortages now appear in most parts of the world, rich and poor – US plains, Beijing, Madras, Mexico – simply because of over-consumption, too many people demanding too much of a limited resources. Since 1960, for example, the Aral Sea has shrunk to about 10 percent of its original area.

Population, consumption & technology

During the 1970s, American ecologists Paul Ehrlich and John Holdren published a now-famous formula to account for human ecological impact on the Earth’s systems: I = PAT, indicating that ecological Impact (I)  is equal to  Population (P) times Affluence (A), or average consumption, times a factor for Technology (T).

Stated simply, the human impact on the planet is proportional to a certain population consuming a certain amount of resources per person, using particular technologies, such as coal, hydrocarbons, automobiles, nuclear power, and so forth. The point is: population is a factor, not to be ignored.

This formula has been useful, but one obvious flaw in this formula, we now know, is that the “Technology” factor is non-linear, meaning that a simple change in technology can create a large, exponential leap in ecological impact. Consider for example the exponential impact of deep sea drilling after the British Petroleum oil-well blowout in the Gulf of Mexico, or the exponential impact of a disaster such as the Fukushima nuclear meltdown. A nuclear war would be the ultimate exponential impact.

Another reason we must consider the exponential impact of technology is that the living ecological system may also respond with its own multiplying effects. Every time we disturb nature, we set in motion a sequence of system responses, which then have their own impact, usually beyond our control or influence. We witness this with global heating. Carbon in the atmosphere heats Earth’s air, land, and water, but the heating itself creates feedbacks that include: Melting permafrost that releases methane, which increases heating; melting ice that reduces Earth’s reflective qualities (albedo), retaining more heat; dying forests that absorb less carbon; increased wildfires; and so forth.

The formula should more accurately be I = PATS; the ecological impact of humanity is related to population and per-capita consumption, as well as to technology and systems feedbacks, which can be non-linear, or exponential, factors.

The wealthy nations and wealthy consumers have, of course, the greatest impact, but sheer numbers do count. There are ways that we can stabilize human population without unpleasantly imposed restrictions, namely with universal women’s rights, education, and available contraception. We can hope that in 2014, the United Nations adopts these policies and takes serious action.

Rex Weyler