The human race is facing a population implosion, faster and sooner than we previously understood. What does this mean for us?Every year, the UN updates its forecasts for the global population. In 2019, the median prediction saw us hitting a peak of around 11 billion humans at the end of this century before our numbers start to decline.11 billion is a lot of humans. The planet could easily support that many, if we all adopted certain lifestyles and policies. But not if everyone wants to live like people do in Britain or America. And there's a good argument that says "Why shouldn't they?" After all, we have spent decades squandering the planet's resources to feed ourselves and our economies. So 11 billion people on the planet was going to be tough. Not only would it accelerate climate change, feeding that many people would be made harder by the effects of climate change. But at least we could see the population peaking. And we could begin to plan for its decline.

Shrink to save the planet

The problem with a declining population is that global disasters aside, it generally means a fall in the birth rate. That means that the population is ageing as it shrinks. Which in turn means fewer young and working age people are available to support the older members of the population, either through taxes or through direct support.Nonetheless, given the pressures of climate change, and the reasons *why* the population was peaking - rising global wealth and the emancipation and education of women - it was clearly a good thing. And while some countries where the birth rate is already low were already starting to struggle with an ageing population, at a global scale it was something we had decades to learn how to deal with.Then came a new report.

Population implosion

The report from the University of Washington's Institute for Health Metrics and Evaluation shows the global population peaking lower and sooner. Instead of 2100 it will peak in 2064. And instead of 11 billion it will peak at 9.7 billion. The global fertility rate will be down to 1.7 by the end of the century.What does this mean? Let's start with the good news. It means women around the world have more power and control over reproduction. And while this is probably too little, too late to have any real impact on catastrophic climate change, it will reduce the scale of the mitigation challenge - a rather euphemistic way of talking about the feeding and rehousing of millions of people.Bad news? This population implosion is happening much faster than we thought at a global scale. Here in the UK, the effects aren't predicted to be that dramatic in terms of total population but some countries like Italy, Spain and Portugal, are predicted to see their populations halve by 2100. This will see a collapse in the tax base and workforce while the cost of caring for an ageing population rises and rises. And it starts now.

Policy response

So what do we do? The first response to this population implosion must be to shore up programmes that support women's education, work, and reproductive rights. As the economic consequences of this population decline become clear, there are bound to be those whose solution is to drive women back to a role as mother and home maker. Setting the policy tone now by addressing the remaining imbalances will make the coming battles much easier.Then we need to look at relatively short term measures to our ageing population. Immigration is the most obvious solution, politically unpopular as it is in many places right now. Populations in India and Nigeria are going to continue to grow through the end of the century. Rather than closing our doors we should be opening them and inviting people in. Based on this report it seems many countries are likely to incentivise immigration within a few decades.Technology will play a huge role. There is a lot of squeamishness about robots and automation in care and health contexts, as I have written about before. But technology can alleviate the burden of some routine and unskilled tasks from care workers, giving them more time to offer personal contact and companionship.Public health campaigns will also be critical. If we can help people to look after their own health, and extend people's healthy, productive years by one, two, or even five on average, then we can drastically reduce costs to the state.This is likely to be married to an extension to the working age. Don't expecting your pension before 70 or even 75, so staying healthy as long as possible will be critical.

The turnaround

The longer term question becomes one of species survival. With a birth rate at 1.7, the population will continue to shrink. Will we see it return to more sustainable levels, around 2.1? I think we will.There is an element of techno-optimism in this view, but I do believe that perhaps in the next century we will reach a level of global health and wealth where most of us are living much longer, healthier lives, with average lifespans rising over 100. If you think that is overly optimistic, just look at the changes in the last century.Investments in women's medicine should see the trauma and risk of childbirth reduced over this period. Greater political equalisation at home and in the workplace, should make it easier for women to have children without damaging their careers. And with better medicine and extended lifespans, having children later in life will be more common.The population is likely to decline a long way before any of this happens. We may find we settle in the 5-6 billion range before it does. And post-climate change, the world will look very different then.