After the Spike

The Risks of Global Depopulation and the Case for People

De: Dean Spears, Michael Geruso

Brought to you by Penguin.

An eye-opening exploration of humanity’s unprecedented path to global depopulation and why it's in everyone's interests to prevent it

IIf we continue as we are, with birth rates falling globally, the world’s human population will peak in the next few decades – and then begin a sudden and rapid decline. It would be easy to think that fewer people would be better: better for the planet, better for the people who remain. In After the Spike, two leading population economists ask us to think again.

Carefully weighing the evidence and the many claims that surround this controversial subject, Dean Spears and Mike Geruso explain why depopulation is not the solution we urgently need for the climate crisis, nor will it improve lives. Far more likely is that the progress which has raised living standards so dramatically over the last two centuries will slow or even reverse. As humanity’s future shrinks, it will become more fragile and less certain, and harder for us to escape from global poverty, disease and injustice.

Halting this decline and stabilising the population need not mean sacrificing a greener future or reverting to past gender inequities. In fact, they argue, it can only be achieved with women’s reproductive rights and individual choice as driving forces. But if we want future generations to enjoy lives even better than our own, it’s time to take seriously society’s collective task of lifting the burdens of parents and other carers.

Deeply reasoned and uncompromisingly humane, After the Spike sheds important light on a dramatic shift in the human story and asks us to consider what future we should want for our planet, our children, and one another.

© Dean Spears and Michael Geruso 2025 (P) Penguin Audio 2025

Reseñas de la Crítica

With stunning clarity, Spears and Geruso show why our assumptions about population, progress and prosperity are leading us astray. If you want to understand where humanity is going, and why that matters, this book is essential reading (Daniel H. Pink, author of Drive)

Fascinating, thoughtful and timely. In ten years, everyone will be talking about global demographic decline and what to do about it (Simon Johnson, Nobel Laureate in Economics)

Spears and Geruso take us by the hand to understand the most dramatic period of human history – and what could happen next. The insights and rigour – which come thick and fast – are matched by human and empathetic narrative throughout (Hannah Ritchie, author of Not the End of the World)

Spears and Geruso meticulously take apart all the myths and confusion surrounding the incoming demographic changes for our species. I had my mind blown over and over and over (Zach Weinersmith, co-author of A City on Mars)

A remarkable blend of empirical research and philosophical argument that has challenged, and changed, my thinking about population (Peter Singer, author of Animal Liberation)

After the Spike reveals how humanity has come to a profound turning point in its history and dissolves our preconceptions about population through evidence, rigour, and a deep compassion for all (Toby Ord, author of The Precipice)

As stirring as it is thoughtful, rigorous and morally uncompromising. After the Spike shows why a stable population is not just compatible with climate action, gender equality and a higher, equitably-distributed standard of living, but why it may just be their necessary condition (Anastasia Berg, author of What Are Children For?)

The most interesting and important book I’ve read in years, packed with eye-opening and surprising facts (Katy Milkman, author of How to Change)

A fascinating introduction to one of the most important policy questions of our time. This engaging, informative book will make you question what you have heard about population. With depth and nuance, it shows how parenting can be reclaimed as a progressive cause (Maya Eden, co-editor of Economics and Philosophy)

I don't agree with every suggestion in this book of course, but I think it offers up some interesting and important conversations that we’d do well to take seriously. And a world in which parenting is easier would be a huge improvement! (Bill McKibben, author of Here Comes the Sun)