After the Spike

Most people on Earth today live in a country where birth rates already are too low to stabilize the population: fewer than two children for every two adults. In After the Spike, economists Dean Spears and Michael Geruso sound a wakeup call, explaining why global depopulation is coming, why it matters, and what to do now.

It would be easy to think that fewer people would be better—better for the planet, better for the people who remain. This book invites us all to think again. Despite what we may have been told, depopulation is not the solution we urgently need for environmental challenges like climate change. Nor will it raise living standards by dividing what the world can offer across fewer of us. Spears and Geruso investigate what depopulation would mean for the climate, for living standards, for equity, for progress, for freedom, for humanity’s general welfare. And what it would mean if, instead, people came together to share the work of caregiving, making parenting better, and stabilizing our numbers.

With new evidence and sharp insights, Spears and Geruso make a lively and compelling case for stabilizing the population—without sacrificing our dreams of a greener future or reverting to past gender inequities. They challenge us to see how depopulation threatens social equity and material progress, and how welcoming it denies the inherent value of every human life. More than an assembly of the most important facts, After the Spike asks what future we should want for our planet, for our children, and for one another.

"After the Spike is an important book. Demography is destiny; Spears and Geruso tell a surprising story and show us how to shape that destiny for a sustainable, flourishing world." ―Anne-Marie Slaughter, CEO, New America and author of “Why Women Still Can't Have It All”

“Most books about the future focus on technology, but AFTER THE SPIKE shows that the real story may be people—or rather, the lack of them. 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, #1 New York Times bestselling author of The Power of Regret, When and Drive

“Read this to understand the most dramatic period of human history—how a global population of millions became billions—and what could happen next. Spears and Geruso’s insights and rigour are matched by human and empathetic narrative.” ―Hannah Ritchie, author of Not the End of the World

“After the Spike is the most interesting and important book I’ve read in years. Spears and Geruso explain why Earth’s population is headed for collapse if we don’t make dramatic changes, and they do it using rigorous analyses, compelling data, and striking visual evidence. After debunking common myths about why this crisis might not be bad news, they offer thoughtful, research-backed guidance on how humanity can respond. Packed with eye-opening graphs and surprising facts, After the Spike is a must-read for everyone on our soon-to-be lonelier planet.” ―Katy Milkman, author of How to Change, and Professor at The Wharton School of the University of Pennsylvania

“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 and The End of Nature, founder of the environmental organizations Third Act and 350.org

“As our political and demographic conversations shifts from panic about over-population to panic about de-population, Spears and Geruso present a clear-eyed and compassionate argument about what we have to lose – not just from the worldwide drop in births already underway, but also from harmful and counter-productive attempts to boost births by coercing women’s and couple’s childbearing decisions.” ―Diana Greene Foster, author of The Turnaway Study, MacArthur Fellow, professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco

“This is popular economics at its finest. Dean and Mike meticulously take apart all the myths and confusion surrounding the incoming demographic changes for our species, while making clear the enormous stakes for freedom, equal rights and human prosperity. Rarely has such an explosive topic been treated with such a combination of urgent and patient explanation. I had my mind blown over and over and over, and you will too.” ―Zach Weinersmith, coauthor of A City on Mars

"What an eye-opener: Spears and Geruso masterfully weave together demographic data, economic theory, and vital moral insights into a gripping tale of loss to come. They explain where humanity is headed if we don't change course soon, and why it matters so much that we find a better path." ―Dr. Richard Y. Chappell, author of Parfit’s Ethics and the Substack Good Thoughts

"In this sharp and engaging book, Spears and Geruso make the case for people—a case that must be made, as the existing and foreseeable path of fertility leads to the end of us. The poet Robert Frost pondered whether the end would come from fire or ice, but Spears and Geruso argue it may come from people simply not choosing children. This book is full of wisdom on this existential question.” ―Lant Pritchett, Harvard Kennedy School

"Too much of the global conversation on falling birth rates runs on a cherry-picking of sporadic changes in data, on ethno-nationalist beliefs and with a deeply patriarchal approach to the space for women in this conversation. Dean and Mike's book recentres the conversation to a spot where many of us who have felt unable to enter this conversation can now begin: a place where good data from around the world (including India) is marshalled and discussed even-handedly, a place where all positions and opinions are fairly evaluated, and a place of vulnerability, where even subjective biases and preferences can be frankly spoken of. India in particular should matter deeply to the global conversation, for its history, its outlier position in many ways, and its complexity, and in this book, it more than receives its due.

"Given the authors' mastery of their subject and vast research that has gone in, this could well have been a book that positioned itself as the ultimate authority on the topic. But for me the most valuable part is its acceptance of the things that we do not fully know. This is not just a bold and innovative book, it is also unusually honest, and an easy, engaging read for a non-academic like myself. It ends with a call to action that young readers in particular will appreciate, after too many years of hand-wringing that have made the world seem much bleaker than warranted. In India and the developing world, I am delighted that the book will come to readers and policy-makers at a crucial moment, and could reshape how we think about the future of people and progress."

―Rukmini S, first data editor in any newsroom in India and author of Whole Numbers and Half Truths