As most of the world’s governments are puzzling out what they can offer to combat global climate change, a sensitive but critical aspect of the problem is coming into clearer focus: population. The word appears 20 times in a new 66-page synthesis of country pledges to cut greenhouse-gas emissions by the UN Framework Convention on Climate Change’s Secretariat. And those are the mentions of population in the context of size or growth, not the word’s more frequent use as a synonym for “people.”

This follows the strongest statement yet from the Intergovernmental Panel on Climate Change (IPCC) one year ago on the contributions of population growth to rising greenhouse gas emissions. The IPCC for the first time also touted the benefits of wider access to voluntary family planning services.

This growing awareness matches one of the emerging conclusions of the Worldwatch Institute’s Family Planning and Environmental Assessment project: Researchers around the world are increasingly recognizing the strength of the population-climate change link.

This isn’t to say that population dynamics will gain serious attention at the upcoming climate conference in Paris beginning on November 30. The topic remains too fraught with the potential for shaming of high-fertility groups and individuals, and scars from coercive “population programs” by some governments in the past. Yet the question of how changes in population influence changes in the environment, and how people respond to them, cannot be wished away. The new UN report helps show why.

Surveying Country Pledges

The country pledges to reduce emissions – “intended nationally determined contributions,” or INDCs, in climate-speak – offered in advance of Paris mark an intriguing step forward for governments.

For the first time, both developed and developing countries are being asked to quantify the proportion of global emissions reductions they can contribute between now and 2030 to help keep the planet’s average temperature from rising more than two degrees Celsius higher than the pre-industrial average. Countries were given until October 1 to submit their INDCs to the UNFCCC Secretariat. The synthesis report summarizes these contributions, covering 146 countries and the European Union. (Since the report’s October 30 release, several more countries have offered pledges. Notable silences so far include such major oil producers as Saudi Arabia, Venezuela, Iran, and Nigeria. The country reports are posted on this UNFCCC page.)

Per-capita emissions will need to decline to meet and sustain pledges as populations grow

In order to fit their pledged contributions into the global picture, governments must consider how many people will live within their borders in 15 years and how per-capita emissions multiplied by population might evolve. Any specific pledge a government makes to cut, cap, or restrain growth in national emissions, it soon becomes obvious, will be more challenging to achieve the more a country’s population grows. Per-capita emissions will need to decline to meet and sustain pledges as populations grow.

The authors of the UNFCCC synthesis report make clear they’re taking into account different population growth scenarios for the next decade and a half and imply that some individual countries are as well. Impressively, the synthesis report authors reference the latest UN Population Division estimates and projections of world population, which only came out this July. Without naming names, the UNFCCC authors also suggest that a few governments aren’t using the best – or any – population data in calculating “business-as-usual” emissions scenarios.

The mentions of population change in the synthesis report go beyond population projections. Some governments also want the world to know that population growth is a significant challenge as they try both to restrain emissions and adapt to climate change already experienced or expected. Several governments state, the UNFCCC authors report, that their countries’ population growth or density constrains their ability to adapt to climate change and protect their citizens. (This concern is reminiscent of statements on adaptation submitted several years ago by a few dozen least-developed countries, most of whom cited population growth, density, and pressure as challenges for adapting to climate change.) A few governments reserve the right to amend their pledges in the future depending on changing circumstances, including demographic ones.

Not Just Climate Change

None of this is surprising. Non-government researchers and advocates have called attention to the connections between population and climate change for years. At the same time they’ve touted the co-benefits that improving reproductive health, education, and the status of women worldwide has for climate change adaptation and mitigation.

Recently the Worldwatch Institute joined the Population Reference Bureau in assembling an expert group from the reproductive-health and climate fields to consider the link the effect that family planning has on climate-compatible development. In our recommendations, we tried to make clear that there is no reason to stigmatize the relationship. The population perspective on climate change is not about pointing fingers, but linking arms – in developed as well as developing countries – to empower women and men to achieve their desired family sizes and improve the wellbeing of current and future generations.

Properly managed and sensitively expressed, connecting population and climate change can support epochal improvements in the lives of women and girls. It supplements the many other arguments for sweeping away barriers to the use of contraception in all countries. Even the IPCC authors understood this point, noting that some industrialized countries with high per-capita emissions have high levels of unintended pregnancy.

Connecting population and climate change can support epochal improvements in the lives of women

Linking population and climate change conceptually may also help combat gender-related abuses that could hardly seem more distant from climate change, such as child marriage. Some preliminary research indicates that child marriage may set back low-income countries economically in part because very young wives are often pressured to bear children early and often. The resulting high fertility rates lead to a higher proportion of dependent young people to economically productive adults – the reverse of the much-touted “demographic dividend” that helps economies prosper. The same high fertility increases population growth, contributing to the challenges some governments say hold back their efforts to mitigate and adapt to climate change.

They’ve only just begun, but the world’s governments are at last sketching out what will be needed to avoid catastrophic climate change. The task is so daunting its achievement will require us to conjure up innovations and ways of thinking and behaving that no one can foresee today; a hero’s journey in which we all receive the call to adventure.

The impact of population on climate change and other environmental changes is so important, albeit complex and notoriously hard to talk about, that governments are being compelled to explore and acknowledge the relationship. The new UN synthesis report illustrates an interesting development: As national governments plan for and try to constrain climate change, they may pull international agencies and experts into more dialogue on demography too. Vigilance to assure that any policies that result are based on the rights and reproductive choices of individuals and couples can help assure that this emerging interest promotes human well-being in more ways than one.