-Open Letter-

PARIS — In the weeks since France's popular environment minister, Nicolas Hulot resigned, after expressing disappointment with President Emmanuel Macron"s environmental record, newspapers have been filled with articles and opinion pieces sounding the alarm. Those in power are told to take vigorous and urgent ecological action to reduce consumption of polluting energies and output of waste, to increase the efficiency of the means of production, and other familiar responses.

And yet it is striking to note that population growth is absent from these discussions. It's as though demography and the environment were two separate issues. In fact, they are inextricably linked.

Efforts to improve eco-efficiency in developed countries remain the top priority over the short term. But the combined effects of future population growth and the inevitable increase in per capita consumption (in developed and, to a greater degree, developing countries) will be truly catastrophic for the planet over the medium to long-term. Effects will include the destruction of biodiversity, threatened water resources, sea level rise due to glacial melt, reduced fish stocks, degraded and salinated farmland, the mass displacement of people, and a temperature increase of over 5 °C by 2100 in France, with highs of over 50 °C.

To avoid this catastrophe, we must drastically reduce our greenhouse gas emissions, especially in developed countries. This is the energy transition. But we cannot overlook the need to significantly decrease global population growth. This is the demographic transition, and it has yet to be achieved in many parts of the world.

More than 11 billion humans by 2100?

The global population has already grown exponentially, skyrocketing from 2 billion to 7.6 billion between 1950 and 2017. The authoritative United Nations population prospects, last released in 2017, indicate that based on the median hypothesis, the global population will reach 8.6 billion by 2030, climbing to 9.8 billion by 2050 and to 11.2 billion by 2100. Notably, these average forecasts tend to increase over time. In 2011, for example, the UN predicted a global population of 10.1 billion by 2100. Although growth will occur on all continents, Africa will be the site of more than 50% of it between now and 2050, and more than 85% between now and 2100 (according to the average hypothesis, the continent's population will reach 4.3 billion by 2100).

During the COP23 in Bonn, Germany, in 2017, 15,000 scientists from around the world published an urgent warning regarding the planet's habitability. They recommended that demographic measures be taken to significantly reduce fertility rates. Although this issue impacts many parts of the world, we will be using Africa as an example due to its cultural proximity to France and because of a major event that happened there, one which we see as positive.

A protest during the COP23 in Bonn, Germany, on Nov. 5, 2017 — Photo: Leonhard Lenz

At a conference in Ouagadougou, Burkina Faso, in July 2017, the parliamentary presidents of 15 countries in the Economic Community of West African States (ECOWAS), as well as Chad and Mauritania, drafted a charter. Aware that overly large populations are an obstacle to their economic development, they committed to working to lower their respective fertility rates to three children per woman by 2030.

Their approach is based on the idea that it's up to women to decide how many children they want, when they want them, and with whom. But education is key: health workers must go door-to-door to offer women a range of contraceptives. Audio messages, for example, must be broadcast to the community in various dialects, and via cell phones.

All this is possible. Certain countries — Ethiopia is one of them — have made the effort, and the results are very encouraging.

The funding can be found.

All this costs money. But funding could be found in existing budgets, without additional spending commitments. We ask that France and Europe help these courageous African states implement their fertility-rate reduction program. In the 2015 Paris Climate Agreement, rich countries committed to paying less-well-off nations $100 billion a year to fight climate change.

It is clear that demographics directly impact carbon dioxide emission increases, and the climate as a whole. Therefore, it is perfectly legitimate to earmark a significant portion of this aid for "reproductive health" (contraception and family planning) programs. This policy would also improve the well-being and quality of life of women, who are most often the first to suffer from the present situation.

We must also do everything possible to spur economic development in poor regions with high birth rates. Doing so is one of the best ways — thanks to women's education in particular — to get women to change their behavior and limit the number of children they have.

This is undoubtedly the biggest challenge we must solve collectively over the next 20 years. But as there is no planet B, halting world population growth is an absolute necessity to save our world from impending disaster.

*Collective: Jean-Claude André, Jacques Bentz, Jean-Loup Bertaux, Albert Bijaoui, Jacques Blamont, Philippe Blime, Christian Bordé, Roger-Maurice Bonnet, Guy Brasseur, Marie-Lise Chanin, Claude Darmon, Bruno David, Bernard Esambert, François Forget, Alain Hauchecorne, Georges Jobert, Rosine Lallement, Serge Michaïlof, Michel Pébereau, Jean-Claude Pecker, Philippe Waldteufel.