can cope with incremental challenges and adapt but beyond a certain tipping point they collapse. Ecosystems are particularly vulnerable to changes in resource availability, climate conditions and of course the introduction of invasive alien species. And we often identify other wildlife species not native to an ecosystem as invasive species but we forget a pretty big mammal which is present today in pretty much all ecosystems on Earth: humans.
The risk of overpopulation is often considered the elephant in the room. Indeed, a few years back some academics expressed frustration that the issue of human population no longer featured in the agendas of organisations fighting for a more sustainable future. Simply put, these eminent academics argued that global challenges such as climate change and global pollution cannot be adequately tackled without addressing the issue of the world’s booming population. Specifically, Professor Chris Rapley, Director of the British Antarctic Survey, makes a powerful argument that while emissions reduction is of critical importance, “the truth is that the contribution of each individual cannot be reduced to zero. Only the lack of the individual can bring it down to nothing”¹.
Similarly, Professor John Guillebaud, Emeritus Professor of Family Planning and Reproductive Health at University College London, claims that given population trends “there no way that a population of nine billion – the UN’s medium forecast for 2050 – can meet its energy needs without unacceptable damage to the planet and a great deal of human misery”¹.
And it is true that population growth trajectories are astounding: in 2011 alone an extra 76 million people was added to the 6.5 billion already living on Earth, which is twice as many as in 1960¹. By 2050, the UN expects that 200,000 people will have been added each day. To look at specific countries, China is the most populous country today with more than 1.3 billion people; India is second with more than 1.1 billion. By 2030 India will have exceeded China with a population of 1.5 billion¹.
So given this unprecedented increase in population numbers, it is hard to imagine how living standards can be maintained given our planet’s resources. According to several global studies, by 2025, more than half of the world population will be facing water-based vulnerability while already by 2030, in some developing regions in the world, water demand will exceed supply by 50%². A similar story emerges when we look at other rates of resource consumption, for examples a study by the UNEP Global Environment Outlook found that “human consumption had far outstripped available resources” and that “each person on Earth now requires a third more land to supply his or her needs than the planet can supply”².
And while the numbers sound compelling, as Professor Rapley acknowledges, human population concerns and planning policies are very emotive issues, giving rise to concerns over ethics, morality, equity and practicability. At the same time, while many Western European countries have family policies that primarily seek to boost births, China’s one child policy has received a lot of criticism.
So on balance, it is undeniable that population growth does have a great impact on ecosystems. We need to bear this in mind as it should provide us with further impetus to address global environmental and sustainability challenges. However, whether this is something that policy-makers should seek to address as a matter of priority is a more difficult issue to address. Given that we have solid evidence that indicates that we can meet these global challenges without seeking to control human population, it might be better if we focused collective efforts on implementing those policy recommendations.