Thread by @stevenbjohnson

THREAD: If you had to pick one chart to represent the last hundred years or so of the modern age, what would it be? I think it would have to be this one, tracking the changes in global life expectancy from 1900 to today.

A century ago, at the end of the Great Influenza, global life expectancy was in the mid 30s. In the US, it was 47. In places like India, it was in the mid 20s, lower than the average lifespan in most hunter-gatherer societies.

Average lifespans were so low in part because childhood was shockingly dangerous. Roughly a third of all children died before reaching adulthood.

Today, just a hundred years later, in the middle of a global pandemic, global life expectancy is in the 70s. Childhood mortality worldwide has been reduced by a factor of 10.

The doubling of human life expectancy is the single most important development of our era. If a newspaper came out only once a century, that extra lifespan would be the banner headline: world wars, moon landings, the Internet would all be below the fold.

But because doubling life expectancy happened slowly, the aggregate result of countless interventions, we don’t recognize it for the achievement it is. Far more people know about the moon landing than, say, the eradication of smallpox.

That blind spot has consequences: think of all the Hollywood films, monuments, taxpayer dollars devoted to celebrating and supporting our military forces, and the tiny fraction of that money and attention devoted to the heroes of medicine and public health.

Doubling life expectancy is so momentous because it is so intimate and global at the same time: all those extra days of life you get to experience, the children you didn’t lose in infancy who get to grow old enough to have their own children.

But the global effects are just as significant, and they create their own challenges. We added 5 billion humans to the planet since 1920, not because people were having more babies, but because we figured out all these new ways to keep people from dying.

Global threats like climate change are also a byproduct of these public health and medical revolutions. If life expectancy had stayed where it was, atmospheric carbon levels would be much lower than they are today, because there would be far fewer humans.

And the COVID-19 pandemic—arriving right on the centennial of the end of the Great Influenza—is a reminder that continued progress in extending our lives is not inevitable.

That’s why it’s essential to understand how we managed to pull off this extraordinary feat — and what we need to do to ensure the benefits of extended life are shared by all communities.

And so I’m thrilled to announce a new multi-platform project, one I’ve been working on for the past four years. Extra Life: A Short History of Living Longer. Launching in early May of this year.

The Extra Life Project is: a four-part PBS series that I am co-hosting with the brilliant @DavidOlusoga, produced by @Nutopia_tv, the same team that created How We Got To Now. Premiering on May 11 at 8PM EST, so set your DVRs.

The PBS series cuts back and forth between 300 years of history of public health/medical breakthroughs and the current battle against COVID-19. All-star guests as well: Anthony Fauci, Kizzmekia Corbett, Larry Brilliant, and more.

A new book written by me, published by Riverhead, hits bookstores on May 11 as well. (You can pre-order now.) A middle-grade version for younger readers is in the works, to be released sometime in 2022.

The project also includes a special issue of the @NYTmag devoted to the past and future of life expectancy, and an educational curriculum to teach this important history, designed by the @pulitzercenter.

Many thanks to all the organizations who have helped make this happen, particularly the @SloanFoundation, the Arthur Vining Davis Foundation, and @OurWorldInData.