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What's likely to cause human extinction – and how can we avoid it?

Stanford epidemiologist Stephen Luby sees three potential outcomes for humanity by 2100: extinction, the collapse of civilization with limited survival, or a thriving society. 

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Potential threats in the coming decades may stem from population growth, increasing environmental destruction and the acceleration of some technological capabilities. But there are also reasons for optimism. (Photo credit: Greg Rakozy / Unsplash)

Every investor in Silicon Valley wants to see a hockey stick-shaped line on the graph showing exponential growth when evaluating a start-up. Few people anywhere want to see the same line plotting the path to human extinction.

Steve Luby, MD, an epidemiologist and the director of research for Stanford’s Center for Innovation in Global Health, sees hockey sticks on chart after chart of the various ways that humans can cause our own demise. It sounds bad, but read on: Luby remains an optimist who is committed to a thriving human society.

As part of the center’s Planetary Health lecture series, Luby gave a talk titled, “Can our collective efforts avert imminent human extinction?”

In the end, Luby comes down firmly on the side of yes, we can. But along the way and without intervention, the future looks pretty grim. By 2100 – a short 81 years in the future – he sees three potential outcomes: human extinction, the collapse of civilization with limited survival, or a thriving human society. The first two outcomes could be the result of population growth coupled with the increasing destruction of our planet.

Without a thriving biosphere, there is no human future.

Stephen Luby Professor of Medicine (Infectious Diseases), Senior Fellow at the Woods Institute and the Freeman Spogli Institute, and Professor, by courtesy, of Health Research and Policy (Epidemiology)

The growth in global population follows a flat line for most of human history and then, at the turn of the industrial revolution, the line shifts to nearly vertical – like a hockey stick – as the population explodes. The same shape show growth in technology and innovation –flat for thousands of years and then suddenly germ theory, telephones, airplanes and the internet, all within a few hundred years.

Sadly, a graph showing the increasing destruction of our environment would have the same shape and would lead to our demise.

“Without a thriving biosphere, there is no human future,” Luby said.

Also threatening that future? Our recently acquired abilities to destroy each other with nuclear weapons and lethal synthetic biology. As an example, CRISPR, a gene-editing technology, could be a force for good used to help eradicate disease or it could potentially be used to cause harm, such as by genetically modifying bird flu to become airborne. And, as Luby sees it, “There’s no shortage of sociopaths.”

Potential danger also lurks in the acceleration of artificial intelligence. AI doesn’t need to turn evil, just competent, to threaten a human future, Luby said. As an example, a machine that is indifferent to human survival could be programmed to create as many paperclips as possible. It may decide to transform the entire biomass into paperclips, he said.

To stick around and survive all these hazards, humans need to become more than competent at looking past our own biases, he said. Short-term thinking, unrealistic optimism and the search for a panacea — the Greek goddess of universal remedies — won’t ensure a thriving future.

For Luby, universities can play a critical role in protecting us. Governments tend to be short-sighted; non-government organizations tend to have limited resources; and corporations are not incentivized to protect humanity. But universities, with multiple areas of expertise and a commitment to interdisciplinary research, may be best-suited to leading to a solution, he said. Universities also have loads of young people with fresh ideas and professors, like Luby, who are committed problem-solving.

“I think humanity is all right,” Luby said. “And I’m willing to lean in to protect a human future.”

Luby is also a senior fellow at the Woods Institute and at the Freeman Spogli Institute for International Studies. 

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Media Contacts

Jody Berger
Stanford Center for Innovation in Global Health
 jlberger@stanford.edu

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