Climate change and population growth

One impact of climate change - and one that we’re beginning to see already - is a rising rate of migration as people move from parts of the globe imperiled by the consequences of a changing climate. That means more people converging on areas that do remain habitable, inevitably driving urbanisation and habitation density and therefore the risks of food and water shortages, and outbreaks of disease. So what role does human population play in all this? With us is Kathleen Mogelgaard from the Population Institute, a non-profit based in Washington, DC, with a missions to "achieve a world population in balance with a healthy global environment and resource base."

Chris - Well, Kathleen, let's begin by looking at the scale of the problem to start with. How many humans do we think there are on earth right now?

Kathleen - The world's population is currently about 7.8 billion people, and it's growing every year. It's continuing, continuing to grow by about 80 million people per year.

Chris - What's that in percentage terms, then?

Kathleen - The population growth rate is right around 1% globally. But of course, when you look at different countries around the world, that percentage growth rate varies quite a bit. We have some countries that are not growing at all. We have a handful of countries that are actually declining in their population. And then we have a set of countries that are growing quite a bit more rapidly than 1% upwards toward 2 and 3% in some places.

Chris - I'm just trying to think about what a 1% growth translates into, because if you, if you work that out, because of course there's 1% this year and then next year, there's 1% on top of the 1% that's just happened. And then the year after that - and so on and so forth, that that would actually translate into quite a considerable growth after not very many years, wouldn't it?

Kathleen - It certainly would. And you know, this is the business of demographers to try to understand where our population is likely to grow in the future. But there are lots of factors that we need to consider when we think about how quickly populations grow and why. And certainly there is a worldwide trend with population growth rates slowing down. We're seeing births around the world still continuing to slow. Although the birth rate is slowing in some places more quickly than in others. So demographers do their best to try to understand how all of these trends come together, including the ways in which development is proceeding. Because we know for example, as girls receive more years of education, as women have greater access to reproductive health and family planning services and greater economic opportunities, you know, all of these areas where we see gender equity improving, then we also see population growth rates slowing. So it's a real task to try to understand how all of these factors come together, that lead toward population growth futures.

Chris - I've just been scribbling while you were talking. It's about a 1% growth about a doubling in the lifetime of the average person listening to this program. So in about 72 years, that's twice as many people than there are right now, if we wait another 72 years and continue to grow at 1%. There's already 8 billion. You're saying that that cannot be sustainable. So what's going to happen?

Kathleen - It's really difficult to predict what is going to happen, but it's really important for us to think about population growth and other population dynamics and how that interacts with our day-to-day lives. And certainly as the world is turning its attention toward tackling the climate crisis, understanding population dynamics and how that relates both to the growth of greenhouse gas emissions, as well as to the vulnerability of human populations around the world, to the impacts of climate change. It's a really important endeavor to understand these demographic trends and to be able to plan for them. We know, for example, that some of the countries that are the most vulnerable to climate change impacts, whether it's the kinds of climate change impacts you were talking about earlier in the program with storm surges and floods, or whether it's the kind of slow onset climate change impacts like multiple years of drought that cause lots of challenges for agriculture, when communities become more food-insecure and that the climate is changing in ways that makes farming very difficult, we know that more and more people will be on the move around the globe. And it's important for us to be able to anticipate that and think about ways that we can make that kind of migration around the world happen in ways that really advances and protects people's human health and wellbeing.

Chris - Are you slightly surprised then given that there has been a lot of hot air, which is ironic from a conference about climate change coming from COP26, and really the only person who has alluded to the population issue is David Attenborough. There have not been very many voices saying this, is that just because people are uncomfortable talking about it, or is it just that people are overlooking the issue?

Kathleen - It's a really good question. That's a difficult question to answer. I think there is a, in many, among many of us, there is a lack of awareness of demographic trends, just how quickly the world's population continues to grow in some areas. I think among some people, they feel like the population problems were a thing of the past, and now we're in some parts of the world worrying about population decline. So I think it's not as much on people's minds as it used to be. But of course we are seeing in many places of the world this ongoing rapid population growth. And when that is combined with climate change vulnerability, the kinds of impacts of climate change that we are likely to see, this is going to have implications for movements of people and the health and safety and wellbeing of people and the planet. So I think it is a really important part of the climate change conversation, but of course, the way our climate change policies are structured, it's done in a somewhat siloed way. So we think a lot about the kinds of technologies that can be put in place to reduce emissions, and even when we're talking about climate change adaptation, you know, the ways in which society will be able to cope with the impacts of climate change, a lot of that discussion centres around some of the hard infrastructure that we were talking about earlier in the program, whether that's sea walls or other kinds of things that will enable communities to be able to cope with flooding or heat waves or extreme weather events. And these kind of longer term trends that relate to the growth of our population and the movement of people are not necessarily on the radars of folks who are thinking about the immediate challenges of adapting to climate change impacts.

Chris - We've got about a minute left, Kathleen. Does the way in which we've really constructed the world economically though, act as something of a barrier to trying to control population? Because if you look at what happened in China, where they had a one child policy that's been reversed because it turned out, you ended up with one poor child trying to sustain two aging parents. And so you ended up with a young married couple with four aging parents trying to be supported between them. So once we sort of get to a population level, it's very hard to row back from that. And we're already, some people say, burning off two planet Earths with resources per year, not one which means we're already well in breach of your mission statement.

Kathleen - I'm really glad you brought up the example of China, Chris. I think it's really, that is a lesson to us about the ways in which population control measures are really a fool's errand. And what we need to be thinking about more is really expanding the rights of people, particularly the rights of women and girls. Around the world, there are hundreds of millions of women who would like to be able to delay childbearing or end childbearing, but they don't have meaningful access to the information and services that would enable them to avoid a pregnancy. And until we really are able to fully meet those needs for women around the world, talking about any kind of top-down population control measure is not, makes no sense from a rights perspective or from an efficacy perspective. If we were able to really fully meet the needs of women and girls around the world, we would see a dramatic slowing of population growth rates. Fertility would decline and we might see population, we might see an end and a slowing or reversal of population growth within this century, but without it, I'm afraid we are headed for a much more crowded world.

Chris - Kathleen, thank you for crystallizing it so well for us. That's Kathleen Mogelgaard from the Population Institute.