Population and Climate Change

By F. Landis MacKellar - 25 September 2018
Population and Climate Change

F. Landis MacKellar explores three areas where demography can be closely linked to climate change adaptation.

In the run up to October’s 48th session of the Intergovernmental Panel on Climate Change (IPPC), researchers have pointed out that the IPCC continues to leave a potentially important policy response – reducing population growth in order to mitigate the growth of greenhouse gas emissions – off the table.   While not disputing that slower population growth is a prudent response to climate change, this essay offers a somewhat broader and more nuanced view of population and climate change.  Any salutary effects of slower population growth on climate will only be felt in the very long term, much too far in the future to interest policymakers looking for short-term wins.  Nonetheless, there are three areas where demography can be closely linked to climate change adaptation: family size, urbanization, and conflict prevention / resolution.  Moreover, an ethical argument on the benefits of climate change response strongly pulls towards adaption, even if it diverts some resources from mitigation.

On 1-5 October, thousands of scientists, government officials, and international organization and non-governmental organization (NGO) representatives will meet in Inchon, Korea for the 48th session of the Intergovernmental Panel on Climate Change (IPCC).  In a new Science paper “Global warming policy: Is population left out in the cold?”, John Bongaarts of the Population Council and Brian C. O’Neill of the U.S. National Center for Atmospheric Research (NCAR) point out that, despite a wealth of research on the relationship between population and climate change, the IPCC has so far systematically ignored the possibility of reducing population growth as a policy means of reducing greenhouse gas emissions.  In these researchers’ calculations, slower population growth achieved by cost-effective family planning programs could reduce emissions by as much as 40 percent in the very long term.  While not questioning their numbers or denying that slowing population growth would be a prudent policy response to climate change, this piece takes a somewhat broader and more nuanced view.

In climate change-speak, reducing emissions is “mitigation” and strengthening resilience in the face of climate change is “adaptation.”   While mitigation lends itself to specifying concrete national actions, costing them, and identifying sources of finance, adaptation is still treated in a vague and patchy fashion; one more informed by advocacy-driven international NGOs than the donors and governments who ultimately decide where to put money.  Yet adding population to the picture suggests three specific sets of actions that can promote resilience starting right now and are win-win in the sense that they pay off regardless of climate change.  Moreover, demography underpins a strong ethical argument to support adaptation even at the expense of mitigation.

The time factor is crucial.  Admittedly, for given energy source mix and level of prosperity, fewer people translate into lower emissions. But reducing fertility can only affect total population in the long term.  Say it is now 2020, which is just around the corner.  The population that will be over thirty in 2050 has already been born and the population that will be under thirty will have been born to mothers born between 2005 (fifteen in 2020) and 2035 (fifteen in 2050). Even drastic fertility reductions in the present translate only slowly into lower population size.  Unfortunately, we live in a world dominated by policy short-termism propped up by widespread climate change skepticism.   Moreover, leaders of many countries, particularly in Africa, bristle when it is suggested that they moderate their rates of population growth (President John Magufuli of Tanzania, where the total fertility rate or TFR is estimated to be five, has just exhorted women to abandon birth control).  Or, apart from exceptions like the leaders of Ethiopia and Rwanda, while grudgingly acquiescing to the policy goal, they do nothing to pursue it.   Global family planning policy since the 1994 Cairo International Conference on Population and Development (ICPD) has been all about individual wellbeing, not population growth.  Finally, do not forget that the world’s number-one greenhouse gas emitter, China, facing disastrous population ageing as a legacy of the coercive one-child policy (and with a suspicious eye on fast-growing India), is struggling to raise its birth rate.  Some other major players, like Turkey and Iran, are doing the same out of pure nationalism.

Between climate change skepticism and resistance to anything sounding like population growth targets, selling population policy as part of the climate change toolkit is difficult and the reluctance of the IPCC, while regrettable, is understandable.  However, there are three sets of interventions to strengthen resilience that have everything to do with demography but need not come with either the politically sensitive “population” or “climate change” label attached.  Call them stealth population and climate change policies if you will.

One coincides precisely with the Bongaarts-O’Neill prescription: promoting the small family ideal and voluntary use of modern contraception as a maternal and child health measure in poor countries, especially in Africa, the Middle East, and South Asia.  Not primarily because it will slow population growth, although that is a welcome side effect, but because, in addition to its benefits for women, smaller family size is good for children, especially girls.  Smaller families are more resilient.  There is no need to wait; the benefits start to flow in the present, and they flow even if the climate change skeptics are right.  Over time, the savings that result from fewer children to care for (the “demographic dividend”) can stimulate growth if they are wisely invested, including in the education of those fewer children.  Moreover, as Bongaarts and O’Neill point out, promoting family planning is cheap; a bargain in international development terms.  For example, the Copenhagen Consensus found that universal access to contraception would yield $120 in social, economic and environmental benefits for every dollar spent.

A second area for action concerns urbanization. The UN’s Population Division expects that the urban share in the Least Developed Countries, 31% of the population in 2014, will rise to 49% by 2050.  Large cities are, for historical reasons having to do with transport, usually located on the coast or in floodplains adjacent to major waterways.  They are vulnerable to storm surges and flooding.  In high-income countries, we muddle through with a combination of post-disaster public bailouts and pre-disaster private insurance, the latter sometimes voluntary and sometimes compulsory.  But in the poorest and most vulnerable countries, insurance is either non-existent or too expensive and governments know that if the worst happens, humanitarian outrage will force donors to step in.  What is needed to address the climate change-population-urbanization nexus is investment in better infrastructure -- roads, bridges, seawalls, housing, power grids, and water and sanitation systems that can withstand the forces of nature – as well as public systems broadly speaking (municipal institutions, civil society organizations, etc.) that can function under stress.  Even absent climate change, better infrastructure and urban governance are needed now if cities are to continue to be the engines of economic growth that they have been.  And there are potential synergies with the family planning policies discussed above, because fewer births in the near term quickly begin to reduce pressure on urban systems; immediately in the case fewer urban births and (more important) in about two decades as fewer rural births translate into lower rural-urban migration.

The third area for action is motivated by the fact that the world’s population is shifting towards its most troubled and troublesome countries, again in Africa, the Middle East, and South Asia.   The UN expects the population of the twenty countries that scored worst on the Foreign Policy magazine Fragile States Index for 2015 to increase their share of world population from 11.9% at present to 18.3% in 2050.  Fourteen of these twenty countries are in Africa, three (Iraq, Syria, and Yemen) are in the Middle East, two (Afghanistan and Pakistan) are in South Asia and only one (Haiti) lies outside these three turbulent regions.  Almost all are experiencing cantering, some full galloping, population growth.  Fragile states are either already embroiled in violent conflicts, whether internal or cross-border, or are at high risk of so being in the future.  Population pressure increases the risk of disputes over scarce natural resources, especially renewable ones like water and land that are likely to be impaired by climate change, while at the same time increasing the complexity of coming to peaceful resolution.  The situation in Africa, where agriculture and property rights are often traditional, ecosystems are precarious, and borders are fuzzy, is particularly fraught.  To address the climate change-population-conflict nexus we need programs to promote better governance where it is possible, more effective approaches to conflict prevention / resolution where it is not and, where bad goes to worse, a nimble international security regime more attuned to putting out brushfires than grand inter-continental strategy.  Over the medium term, about fifteen years, birth rate reductions today will start translating into a smaller youth population, easing pressure on the labor market and secondary and higher education systems.  That, in turn, might have the knock-on effect of reducing the number of potential and aspiring migrants to Europe, a goal now concentrating European policy minds wonderfully.

These three adaptation-related action points – promote voluntary family planning, strengthen cities, and deal more pro-actively with conflicts – are concrete, practically operational.  At a more abstract level, demography can also underpin an ethical argument, first articulated by Nobel-prize winning economist Thomas Schelling over twenty-five years ago, in favor of adaptation, even if it diverts money from mitigation.  It is a view from the North, but we, the traditional and major players in international development cooperation,  what used to be called “foreign aid,” are the ones with the money that can be deployed now.   As it is ours, we should deploy it as we judge best.

Climate, like population, has memory.  Almost all medium-term climate change, like almost all medium-term population change, is already baked in the cake.  Money spent now on reducing emissions will not significantly alter the path of climate change for decades.  The costs of mitigation will have to be borne, whether through own-emissions reductions or helping poor countries to develop clean energy, by today’s high-income countries, with their small and slow-growing populations.  But the fruits of emissions reduction will largely be enjoyed by the descendants of those in today’s populous and fast-growing South – who will live in a world technologically unrecognizable to us; who having benefited from decades of economic growth will not be nearly as poor as they are today; whose values, beliefs, and culture may be far from our own; and over whose future behavior and decisions we have no power. 

As with mitigation, today’s wealthy countries will also have to bear the cost of measures to promote adaptation and resilience.  But, by contrast to mitigation, such programs bring present benefits, in the form of better health, more education, better access to decent work, and higher income to the poorest, towards whom we can target our support with reasonable accuracy.  They deliver these benefits to people whom we recognize, with whom we share a present moral bond, and over whom we have at least a modicum of influence.  They also bring benefits to us, in the form of a safer and better world.

Both climate change mitigation and adaptation are needed.  But thinking about population pulls us in the direction of adaptation.  It points to three areas where interventions will strengthen resilience starting right now, climate change or no climate change.  And it underpins an ethical argument in favor of helping the world’s poorest people in the present, not decades into a hypothetical future.




Landis MacKellar is an economist and lawyer whose published research has spanned demography, the economics of the social sector, and natural resource and environmental economics.  In 2013, he joined the Population Council (www.popcouncil.org) in New York as Senior Associate and Editor of Population and Development Review, the leading journal seeking to advance knowledge of the relationships between population and social, economic, and environmental change.  Mr. MacKellar resides in New York and Paris and  is a frequent consultant to the European Commission as well as other international development agencies and institutions.  The opinions expressed here are his own.

Image credit: Anders Sandberg via Flickr (CC BY 2.0)

Disqus comments