A Scientist’s Warning Odyssey

A Scientist’s Warning Odyssey by William J. Ripple

While giving an invited lecture on the global loss of megafauna in 2017, I became aware of the original World Scientists’ Warning to Humanity from 1992. It had been a quarter century (now the 30th anniversary) since this warning with seemingly little response. This inspired me to write a second warning to humanity to assess humanity’s progress (or lack of progress) using global environmental trend datasets that are now available.

Life changed the day we published this paper. More than 21,000 scientists from 184 countries signed onto the paper as signatories, instigating a mass media frenzy, a string of presentations in various cities, a new documentary film, and the formation of a grassroots citizens group called the Scientistswarning.org.

It felt risky and I was trepidatious about speaking out at first, wondering if I would be judged negatively and discredited by my administrators and peers. But once I got started, I couldn’t stop. In 2020 and 2021, I co-led two similar papers on the World Scientists’ Warning of a Climate Emergency. These were also highly successful papers with thousands of scientist signatories, a strong positive response from global scientists and citizens, and hundreds of news stories. 

Ultimately, my concern about administrator/peer backlash was not well-founded. My science-based advocacy was not only tolerated, but I was honored with the university “impact award”, promoted to a university endowed chair, and a Carbon Commitment Committee was created to speed university progress toward becoming carbon neutral.

My public audiences also grew over time. My first Scientists’ Warning presentation at the local high school had about 20 people, but this grew to hundreds and sold-out entire theaters as I was invited to speak at more venues.

Here is How I Did It

  1. I let go of the fear of repercussion for speaking out to get my message beyond the scientific community.
  2. I focused on communicating the science directly to the public and policymakers.
  3. I wrote understandable, concise papers that could be read within minutes, using impactful graphs that could be comprehended within seconds. I typically put the scientific details in the online appendix.
  4. I developed and refined a presentation about my personal research of ecological field studies, and the Second Warning and Climate Emergency papers. To engage public audiences, I made sure to include personal storytelling, humor, and deeper meaning using NASA’s Earth images.
  5. I spoke out honestly to the press, at climate marches, to my peers, and to public audiences.
  6. I met with members of congress and, as a result, our warning papers were put into the congressional record.
  7. I founded the Alliance of World Scientists, an organization of approximately 26,000 scientists from around the world committed to the well-being of humanity and the planet, speaking out to explain the science, and “telling it like it is” in plain terms.
  8. I worked with a film crew to produce a documentary film; this was a partnership, not just hand-offs with no editorial control. The film, “The Scientist’s Warning”, is now out and freely viewable by the public at www.scientistswarningfilm.org


Scientists’ Pledge

After decades of analyzing data, reading the literature, publishing articles, and teaching, I have concluded that scientists have a moral obligation to clearly warn of any catastrophic threats to humanity, and, in plain terms, ‘tell it like it is’. My personal odyssey illustrates the difference that even one shy but determined scientist can make. I hope my story and the  pledge below inspires other scientists to take action before it’s too late (visit www.scientistswarningfilm.org to take the pledge). 


Scientists’ Pledge: In particular, world citizens need to know that:

  • Business as usual with the ever-expanding human enterprise is unsustainable. 
  • We must act fast and make progress with quick, bold, and transformative change to avoid untold suffering. 
  • Scientists must deliver honest and sometimes even uncomfortable truths to those in power. 
  • Speaking truth to power will have a significant influence on policymakers and outcomes. 
  • The collective voice of many scientists can help turn knowledge into action. 

As scientists, we pledge to stand together to effect positive change, while making a commitment to speak out about threats to life on planet Earth.