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Contraception Editorial June 2012

Seven Billion and 31 Gigatons

Suzanne Petroni

This editorial is adapted from a previous work by the author, “Seven Billion and 31 Gigatons: Making the Population–Climate Connection,” the author's presentation at Reproductive Health 2011, ARHP's annual clinical conference, and “Policy Review: Thoughts on Addressing Population and Climate Change in a Just and Ethical Manner,” which appeared in Population and Environment in 2009 and is cited throughout this editorial.1

The United Nations announced last October that earth's population had passed 7 billion, the largest number the planet has ever seen.2 Only 100 years ago, our planet held fewer than 2 billion people. Global population has doubled in my lifetime, from 3.5 billion in 1968 to 7 billion now. And we are on track to add 2 billion more by the year 2050. 2 That is the equivalent of adding another China, United States, Brazil and Nigeria in less than 40 years.

Media coverage of the 7-billion milestone was mostly somber, with images of crowded cities, belching smokestacks, denuded forests, starving children, polluted rivers and spreading deserts. Some looked at Japan and countries in Europe with declining populations, but that was also presented as bad news: aging people, strained social safety nets, shuttered schools, a dwindling work force — a “baby bust.”

One forward-looking message that came through clearly in the discussions around 7 billion was that we must take better care of the environment if our children and grandchildren are to have sustainable lives.

Indeed, while there may be disagreement about how to deal with a growing global population (see the June 2011 Contraception editorial,3), we do seem to be moving toward a consensus that we really must do something about the strange and scary weather, in the form of monumental tornadoes, droughts, blizzards, extreme temperatures and floods, that we, no matter where we live on the planet, are facing. In other words, we must confront climate change.

Climate change is happening. And scientists agree that it is generally caused by three factors: greenhouse gas emissions, economic growth that fuels energy consumption and population growth that fosters increased greenhouse gas-emitting activities.

In posing strategies to mitigate climate change, efforts have been geared primarily toward the first driver, specifically, reducing energy consumption and developing technologies to reduce emissions.

The idea of restraints on the second contributing factor — economic growth — is far from reasonable in a world where one third of the world's population lives on less than $2 a day.

As to population growth, there has been relatively little scientific attention, but increasing talk nonetheless, about slowing such growth as a way to lessen the emissions pumped into our shared atmosphere. If we can link slowing population growth to mitigating climate change, the argument goes, family planning, which helps to reduce fertility rates and, in turn, slows population growth, will come to be seen as an urgent matter of national and environmental security. And then governments, including that of the United States, will respond with increased funding. But is this really a good idea?

Let's consider what we know.

More than 90% of the world's future population growth is projected to take place in the developing world, where countries are already struggling to provide their people with food, water, health care, education and jobs.4

We know that humanity pumped 31 gigatons of carbon dioxide into the atmosphere in 2010, the largest amount ever recorded.5 To put that in context, a gigaton is one billion tons or the equivalent to the weight of 50 million blue whales. So each year, we are adding 1550 million blue whales' worth of CO2 to our atmosphere, in addition to other toxic gases.

We know that, over time, as population increases, so do CO2 emissions. But as even scientists from the Intergovernmental Panel on Climate Change, the world's leading climate body, acknowledge, while the trend lines run roughly in parallel, the science is far from clear on the connection.

We also know that the need for family planning worldwide is beyond question. Some 215 million women in the developing world want, but do not have access to, modern contraception, which leads to unintended pregnancies, unsafe abortions, maternal and child mortality and morbidity, reduced access to education and a whole range of other negative consequences.6

At the same time, however, I fear that linking family planning to slowing climate change could endanger the fragile consensus that we have achieved about population in the past 18 years: that individual health and rights, including reproductive health and rights, are what matters most in fostering just and sustainable development. No matter what our numbers are.

Let's step back in history for a moment.

Recognizing the vastly expanding global population, governments around the world in the middle of the 20th century began to implement population policies and programs that were geared toward controlling population size and growth. These policies were often accompanied by top-down approaches, including the setting of demographic targets and the institution of programs that actively and even aggressively promoted contraceptive use. Women were sometimes paid, incentivized or coerced to take on long-term contraceptives they might otherwise reject. Forced sterilizations, coerced abortions and other restrictions on reproductive freedom occurred not only in places like India and China, but in the United States as well. Some of these abuses still occur today.

In 1994, at the International Conference on Population and Development (ICPD) in Cairo, Egypt, 179 governments reached a historic agreement that rejected two centuries of Malthusian thinking about population growth. Supported by feminists, human rights activists and environmentalists, the “Cairo Consensus” stated that a sustainable global population would come about not through targets and quotas, but through education, health care and basic human rights. This new rights-based approach included voluntary family planning as part of a comprehensive package that also included maternal and infant health care, prevention of gender-based violence, and prevention and treatment of sexually transmitted infections, including HIV/AIDS.7

The governments at Cairo agreed that they had a collective responsibility to promote what was, at the time, a revolutionary idea: that all individuals had the right to decide freely and responsibly the number and timing of their children. They also agreed to distribute such benefits more equitably among the world's many inhabitants.

Indeed, key to achieving the Cairo Consensus was a promise of funding from industrialized countries for programs in the less-developed nations. But, while US family planning assistance continues to be the world's highest, we have not come close to the levels we promised at the ICPD. Most other countries have not either.

Despite the knowledge that voluntary family planning and comprehensive reproductive health care work to improve the health of women and their children, keep girls in school, enhance economic development and, yes, slow population growth, governments, including that of the United States, have been reluctant to provide the levels of assistance that they promised and that the world needs.

Advocates have tried many arguments to get the United States to meet its commitments, but support has been slow to come. So why not add to the political arsenal the argument that climate change cannot be resolved without increased investments in family planning?

Setting aside the fact that the politics and partisanship around these issues have become so extreme in the United States that any logical argument is likely doomed to fail, let me raise a few other concerns.

First, articulating a close and direct relationship between population growth and greenhouse gas emissions may lead countries which are under pressure to reduce their emissions to what they think is a “simple” solution: reducing their rates of population growth. And if done without regard for individual rights, such policies could turn coercive and prove devastating to human rights and well-being, all in the name of environmental stewardship. China has already made this connection. At a UN conference on climate change, China announced that its one-child policy had reduced the country's CO2 emissions by 1.3 billion tons by preventing 300 million births from occurring.8

Second, making this argument may open the door for individuals in the industrialized world to blame population growth in the developing world for the problem of climate change. But that would be wrong. The United States contains 4% of the world's population but produces 18% of all greenhouse gas emissions.9 As the footprints here show, that is 13 to 25 times the emissions of the typical Indian, Indonesian, Yemeni or Nigerian and 73 times that of the average Bangladeshi (fig 1.).10

Fig. 1. 

Total emissions of CO(millions of metric tons), 2009, figure based on data from Energy Information Administration.1

But what about future population growth, since 95% of it will take place in the developing world?

While we worry for the environment over the growth of countries in the global South, the US population itself is expected to grow by 80 million people in the next 40 years.11 While this is far fewer people than India will add to the planet, it is roughly the same amount as Nigeria expects to contribute, more than Pakistan and more than twice as much as either Bangladesh or Indonesia.12

Unless our consumption and production patterns change dramatically, the United States is expected in the year 2030 to produce more COthan the Middle East, Africa and Latin America combined. Only China's emissions will exceed ours. In other words, the United States will long continue to be the world's greatest or second greatest emitter of greenhouse gases, even as our share of the world's population declines(fig 2.).1

Fig. 2. 

Future emissions — 2030 (millions of metric tons of CO2), figure based on data from Energy Information Administration.1

Given that the US population increase will continue to have significantly disproportionate negative impacts on the climate, we could not ethically consider engaging in a debate about the need to slow population growth in the rest of the world without addressing our own growth rates and emissions production first. I would argue that it would be quite unethical to transfer responsibility to the planet's poorest people for a problem that the United States has been and will continue to be a primary contributor.1

So what can we do?

We can make the argument that generating support among the American public and policymakers for government-supported voluntary family planning — at home and abroad — is, in itself, a worthy and important task. Voluntary family planning is something that is desired by many women and for which sufficient funding and policies do not currently exist, despite government commitments.

Further, as the ICPD affirmed, family planning should not be supported in isolation, but must be enveloped in comprehensive policies of health and sustainable development. Enhancing social development, as well as promoting gender equity and enabling individual responsibility, can contribute to the outcomes we all want: improved quality of life and a healthy planet that can be sustained for generations to come.

These more comprehensive policies start with and focus on the individual, but they also require the commitment of the global community. For the United States, this means that we must understand our obligation, as the world's wealthiest nation, to help others around the world to achieve at least a reasonable minimum quality of life. If we meet this obligation, we will not only assist in improving the health and well-being of millions, but we will also, ultimately, contribute to slowing unnecessary population growth and the impacts that it has on the environment.1

We must also emphasize first and foremost the responsibility that we in the United States have to lessen the damage that we ourselves are doing to the global environment. As I have written before, “if we take seriously a duty to leave a healthy planet for future generations, and if we wish to be a credible voice for solving the challenge of climate change, we must prioritize reducing our own country's production of emissions.”1

And, finally, if we are to engage in a discussion of the connections between population growth and climate change, we must first acknowledge that slower population growth would likely play only a limited role in solving the climate change problem. And, we should start at home. We simply cannot claim that the United States has a right to grow as large and extravagant as we like while talking about unsustainable growth in other countries, especially those that, by comparison, put mere bits of greenhouse gases into our shared environment.

We must not allow any renewed debate about the impacts of global population growth to disrupt the hard-earned global consensus around government-supported family planning. Population policies must prioritize freedom and must be made with individuals at the core because, in the end, it is individuals — not abstract millions — with whom we share the planet.

Suzanne Petroni
Public Health Institute
Washington, DC


  1. Petroni S. Policy review: thoughts on addressing population and climate change in a just and ethical manner. Popul Environ. 2009;30:275–289
  2. United Nations Population Fund . State of the world population 2011. New York: UNFPA; 
  3. Petroni S, Shields W. International reproductive health still worth the investment. Contraception. 2011;83:491–494
  4. United Nations, Department of Economic and Social Affairs, Population Division .  
  5. Harvey F. Worst ever carbon emissions leave climate on the brink. The Guardian; May 29, 2011. 
  6. Singh S, Darroch JE, Ashford LS, Vlassoff M. Adding it up: the costs and benefits of investing in family planning and maternal and newborn health. New York: Guttmacher Institute and United Nations Population Fund; 2011;
  7. ICPD '94: summary of the programme of action. International Conference on Population and Development, United Nations. 1995. 
  8. Doyle A. China says one-child policy helps protect climate. Reuters. 2007 Aug 30.  
  9. Energy Information Administration (EIA) . International energy outlook. Washington, DC: EIA; 
  10. Energy Information Administration (EIA) . International energy statistics. Washington, DC: EIA; 
  11. Passel J, Cohn D. U.S. population projections: 2005–2050. Per Research Center. 2008;
  12. U.S. Bureau of the Census . International data base. 2011

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Used with permission from Elsevier, Inc.