Alliance of World Scientists

27,000 subscribing members from 180 countries

The Alliance of World Scientists (AWS) provides the collective international voice of thousands of scientists regarding the global climate crisis and environmental trends with the intent to turn accumulated knowledge into action. 

The Scientist's Warning is a documentary film about a researcher who started a movement to encourage scientists to help turn scientific knowledge into action. It's the story of scientists all over the world awakening to the need to become advocates for the fate of the planet and the humans who depend on it. The full film can be viewed above and a trailer is available on Vimeo. Both scientists and citizens can get involved and help by scrolling down on this page.

As a class assignment, instructors can have students read the article World Scientists' Warning of a Climate Emergency 2022 and view this as a companion film The Scientists' Warning (35 min.).


Oregon State Productions (link to website)

This film was produced by Oregon State Productions. See their website for details and information on other films.


A list of the crowdfunding supporters who helped fund the production is available here.

The Alliance of World Scientists’ (AWS) Planet Earth Award acknowledges individuals who champion life on Earth. These individuals demonstrate exceptional creativity or contributions in their work in science-based advocacy with the public, policymakers, or other non-scientist groups seeking solutions to environmental challenges.


What can YOU do about climate change? Take this quiz to find out.

Here is the scientists’ pledge that is in the film

A call to action

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.

Please distribute this pledge widely by copying and pasting it, printing it, using this social media card, or sharing the website link. For more information, see the essay A Scientist’s Warning Odyssey by William J. Ripple. A list of the scientists who recited the pledge in the film is available here.

To learn more about science-based advocacy, please see the Communicating Complex Crises toolkit developed by Faculty for a Future.

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World Scientists’ Warning of a Climate Emergency 2022 is a followup assessment of planetary vital signs with a focus on climate-related disasters and extreme weather (see articles in Forbes, The Daily Mail, and CBS News). Please help us promote the paper by sharing materials from our social media toolkit.

We invite all scientists to join the Alliance of World Scientists by signing a short article on climate change

If you are a scientist, we invite you to join the Alliance of World Scientists by signing our Viewpoint article “World Scientists’ Warning of a Climate Emergency” by Ripple et al., which was recently published in BioScience Magazine. We welcome signatures of scientists from any scientific discipline, including graduate students in the sciences. Before signing, we ask that you view this short article by clicking the “Read the Article” tab below (the main text can be read in < 8 minutes), or read the condensed version directly below. When you click “sign the article” and add your name, you will be indicating that you generally agree with our article, helping get this message to world leaders. Note that signatories speak on their own behalf and not on behalf of their affiliated institutions. It may not be possible to sign the article using Internet Explorer, but other web browsers seem to be working. New signatures may take several weeks to appear in the list of signatories because each name will first need to be validated. Please only sign the article once.


Current number of signatories: 15,656 from 165 countries


World Scientists’ Warning of a Climate Emergency: 
French Version and French Supplement



World Scientists’ Warning of a Climate Emergency 
(Condensed Version) 

William J. Ripple, Christopher Wolf, Thomas M. Newsome, Phoebe Barnard, William R. Moomaw


We scientists have a moral obligation to clearly warn humanity of any catastrophic threat. In this paper, we present a suite of graphical vital signs of climate change over the last 40 years. Results show greenhouse gas emissions are still rising, with increasingly damaging effects. With few exceptions, we are largely failing to address this predicament. The climate crisis has arrived and is accelerating faster than many scientists expected. It is more severe than anticipated, threatening natural ecosystems and the fate of humanity. We suggest six critical and interrelated steps that governments and the rest of humanity can take to lessen the worst effects of climate change, covering 1) Energy, 2) Short-lived pollutants, 3) Nature, 4) Food, 5) Economy, and 6) Population. Mitigating and adapting to climate change entails transformations in the ways we govern, manage, feed, and fulfill material and energy requirements. We are encouraged by a recent global surge of concern. Governmental bodies are making climate emergency declarations. The Pope issued an encyclical on climate change. Schoolchildren are striking. Ecocide lawsuits are proceeding in the courts. Grassroots citizen movements are demanding change. As scientists, we urge widespread use of our vital signs and anticipate that graphical indicators will better allow policymakers and the public to understand the magnitude of this crisis, track progress, and realign priorities to alleviate climate change. The good news is that such transformative change, with social and ecological justice, promises greater human wellbeing in the long-run than business as usual. We believe that prospects will be greatest if policy makers and the rest of humanity promptly respond to our warning and declaration of a climate emergency, and act to sustain life on planet Earth, our only home.


The Alliance of World Scientists (AWS)

The AWS is a new international assembly of scientists, which is independent of both governmental and non-governmental organizations and corporations. We submit, that in order to prevent widespread misery caused by catastrophic damage to the biosphere, humanity must practice more environmentally sustainable alternative to business-as-usual. Our vital importance and role comes from scientists' unique responsibility as stewards of human knowledge and champions of evidence-based decision-making. The main goal of the AWS is to be a collective international voice of many scientists regarding global climate and environmental trends and how to turn accumulated knowledge into action. Other organizations do laudable work toward this goal, but to our knowledge, AWS is the only independent, grass-roots organization comprised of scientists from around the world committed to the well-being of humanity and the planet. Dr. Bill Ripple and Dr. Chris Wolf serve as Director and Associate Director of the AWS respectively.

When you endorse the scientists’ warning article, you will have the option of including your email address for occasional communication or additional collaboration as part of the AWS.

Courtesy of Union of Concerned Scientists/Justin Bilicki


For information about donating to our project, please contact Bill Ripple


Global Human and Livestock/Methane Counters and Emissions Trackers


The Ethics of Science

The end that science seeks is truth.
There are rules that must be followed in seeking the truth
which require trust, independence in observation and in thought.
Freedom, respect and tolerance are handmaidens to science.
Scientists acquire knowledge by small steps, none of which is final
and the mistakes of one generation of scientists are rungs in the ladder toward truth. The only purpose of seeking the truth is to accumulate knowledge which becomes the property of the world without respect to race, religion, nationality, political and sexual orientation or cultural beliefs. Science is unifying because it seeks answers which society ultimately hold as important.
-by William Stone, signatory of the second warning to humanity

Diversity and Inclusion

The Alliance of World Scientists is an inclusive group and all scientists are welcome to join when becoming signatories to the scientists’ warning article. Because we understand the complexity of identity and backgrounds of scientists throughout the world, we embrace the diversity of differences these scientists bring for solving environmental challenges. We now have 26,000 scientists from 180 countries as members of the Alliance of World Scientists.

"World Scientists' Warning to Humanity: A Second Notice"

2nd Warning Film Still Image

Oregon State University has formally endorsed the Scientists’ Warning with a joint resolution (pdf) of the faculty senate and the student government.

Recommended Reading

view of planet Earth from space

World Scientists’ Warning to Humanity: A Second Notice is a followup to a previous scientists' warning to humanity, which shows how more progress is needed on environmental issues. According to the authors, "To prevent widespread misery and catastrophic biodiversity loss, humanity must practice a more environmentally sustainable alternative to business as usual. This prescription was well articulated by the world's leading scientists 25 years ago, but in most respects, we have not heeded their warning."

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World Scientists’ Warning of a Climate Emergency is an assessment of planetary vital signs that has been endorsed by more than 14,000 scientist signatories. The authors present a holistic plan for addressing the climate emergency, dealing with (1) energy, (2) short-lived pollutants, (3) nature, (4) food, (5) economy, and (6) population.

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World Scientists’ Warning of a Climate Emergency 2021 is an update to the previous climate emergency report. The authors "reaffirm the climate emergency declaration and again call for transformative change, which is needed now more than ever to protect life on Earth and remain within as many planetary boundaries as possible."

storm as seen from space - decorative

World Scientists’ Warning of a Climate Emergency 2022 is a followup assessment of planetary vital signs with a focus on climate-related disasters and extreme weather. Please help us promote the paper by sharing materials from our social media toolkit.

ocean surface temp anomaly plot

The 2023 state of the climate report: Entering uncharted territory provides an update on planetary vital signs, detailing how life on planet Earth is "under siege." Please help us promote this report by linking to it on social media.

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For more recommended reading, please check out our Scientists' Warning articles page.


Resources for Citizens

Car-Free Living Is Carefree Living

by Kate McFarland

Kate McFarland

Growing up in rural Ohio, I took for granted that every adult human relied on a personal motor vehicle for transportation. However, growing up in rural Ohio, I was also unprepared for the stress and anxiety that would come with driving on busy city streets and multi-lane freeways when I moved to the city for college. Worst of all, perhaps, I had never learned to parallel park (no, pulling back and forth between traffic cones is not the same). As soon as I realized that alternatives were available, reducing my car use was all but an automatic response. I walked whenever possible. I used city buses when necessary. I relearned how to ride a bike (no, it’s not like riding a bike if it’s been long enough). I drove my car every other Saturday morning to keep the battery from dying.

As I relied less and less on an automobile and more and more on active transportation, I felt healthier both mentally and physically. I also experienced unexpectedly deep and transformative changes in my conception of what transportation can and should be. For one, I discovered that walking or cycling transformed transportation from a merely instrumental means of getting from point A to point B to an intrinsically rewarding activity. Every journey is not merely a journey but, at minimum, a source of exercise, fresh air, and awareness of one’s community. For another, I realized that it is the pedestrian who enjoys the purest form of freedom of movement. The pedestrian, for example, can make a spontaneous decision to pause on the sidewalk to window-shop, greet a passing friend, or admire an interesting bird or flower. If she doesn’t stop but then regrets it, she can turn on her feet and backtrack. The motorist, in contrast, is often deprived of the liberty of spontaneity — forced to proceed with the flow of traffic at risk of mortal danger. The pedestrian, in other words, enjoys much greater leisure both to be distracted by her surroundings and to succumb to distraction; it is she, not the driver, who can literally stop and smell the flowers.

When I finally decided to sell my car, it was the most liberating thing I’ve ever done. Gone were all the remaining worries of car ownership – maintenance, insurance premiums, agreeing to give a lift to a friend only to face the embarrassment of being unable to parallel park upon reaching the destination, etc. Best of all, however, it felt to me like the ultimate act of social defiance: I had officially rejected the expectation that all adults must own a car. That was over six years ago. I have never once regretted it.

My next goal was to enjoy the slow-paced and low-stress car-free lifestyle in a more fitting setting than the noise and rush of the city. (story continued here)



I separated from owning cars and riding in cars!

by Melissa Soderston 

Melissa Soderston

When I initially chose to employ walking as my only form of transportation, my goal was to live as ecologically mindful a life as possible while perhaps inspiring others to make more sustainable choices of their own. In the nine years since leaving my car (and even my bike!) behind, it has become an indispensible joy, and I've noticed real change in my community. Living in a tourist area with heavy traffic and very poor pedestrian infrastructure, yet a strong focus on the outdoors, I knew if I could bring awareness to just how walkable the city actually was, that I could motivate others to spend less time in their personal vehicles. I purchased a second-hand wagon to haul groceries, a grabber for picking litter along the way, plastered a smile on my face, and got to walking. And it has worked. Right away, people were stopping to ask what I was doing, or to offer a ride. I would always decline the latter, but it was an opportunity to connect with a wide demographic in an organic way, and share my mission of a pedestrian oriented future. Today, many of my neighbors are walking or biking to work, and we have a strong presence at council and planning meetings to advance not only pedestrian saftey, but to encourage a focus on broader sustainability issues. We also now have access to an extensive and constantly improving network of bikepaths and trails providing safe, off-street access to almost the entire town, including to our schools. Many shopping centers are rethinking their parking areas to accommodate the new foot traffic, and we have many more outdoor entertainment and eating spaces.

The personal benefits have been equally rewarding. Not only am I more in touch with my human community members, I am much more aware of fluctuations in local plant and animal populations and especially those of our declining insect partners. The smile I orchestrated to make myself approachable is now automatic when heading out the door. I go out, socialize and get involved much more frequently than before. And I can daily appreciate the personalities of the clouds, as John Muir hoped we would. We are all well aware of how little time there is to act for the future, and often it can be incredibly difficult to achieve change at the local level. You may find that leaving your cars behind, even if for only some of your outings, may be the enjoyable solution we all need. Hope to see you out there, walking for change!

Enjoying travel on foot, even in the rain

Citizen's Pledge

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Information is power. Facts are power. Collective research from a breadth of scientists has compounded to form a base of knowledge of Earth’s systems and how humans can minimize our impacts on warming the planet. 

It is the moral obligation of citizens to listen to the science and inform themselves of the catastrophic threats to humanity.  In particular, world citizens need to know that: 

  1. Business as usual with the ever-expanding human enterprise is unsustainable. 
  2. We must act fast; we must make progress with quick, bold, and transformative change to avoid untold human suffering. 
  3. It is important to trust scientists, who are unimpeded by bias or self-interest, to deliver honest and sometimes even uncomfortable truths to the public and those in power. 
  4. Citizens also need to speak truth to power, relying on scientific evidence, to have a significant influence on other citizens, policymakers and outcomes. 
  5. The collective voice of many citizens regarding the converging climate and environmental crises can help create a social tipping point for action. Examples include voting, protesting, marching, contacting elected officials, and demanding divestment in fossil fuels.

As citizens, we pledge to stand together to effect positive change, and to speak out about the threats identified by credible scientists.

Here is what you can do

Protesters: Climate emergency
  1. Gain and retain trust in scientists and the scientific process.
  2. Focus on learning scientific facts and communicating them to other citizens and policy makers.
  3. Speak out honestly to family, friends, and even strangers.
  4. Contact elected officials about your environmental or climate concerns.
  5. Stay informed about upcoming elections, and vote for candidates who take environmental and climate issues seriously.
  6. Urge governments to take bold, ambitious action now on both climate and other environmental crises.
  7. Be a discerning media consumer; don’t believe everything you read, corroborate before sharing.
  8. Work together, with science in hand, to combat misinformation.
  9. Join groups and organizations that are working for shared causes.


Please distribute these lists widely by copying and pasting, printing, using these social media cards (pledge; actions), or sharing the website link.


Here are some examples of US-based groups and projects for nonscientists. 

  • Environmental Voter Project   Identifies inactive environmentalists and transforms them into consistent voters to build the power of the environmental movement.
  • Vote Forward   Empowers grassroots volunteers to encourage their fellow citizens in underrepresented communities to vote. It builds tools to facilitate communications between Americans to help strengthen our democracy. Research has shown it has impacted the results of close, critical, elections.
  • Citizens Climate Lobby   Great training on how citizens can lobby their parliamentarians (Members of Congress) effectively by presenting to them a clear and ethical path toward progress.  In the US it advocates persuasively for the Energy Innovation and Carbon Dividend Act and also other solutions.
companion site

Citizens are invited to get involved with our companion grassroots organization Scientists Warning Foundation, working in cooperation with The Alliance of World Scientists (AWS), is a non-profit organization made up of an activist network of researchers, scientists, and global citizen scientists. It is dedicated to bringing people together in order to unite behind the science.

Looking Ahead

Climate change and the concomitant loss of biodiversity and natural resources are such enormous problems that it’s easy to give in to feelings of despair and helplessness. However, my personal story (see A Scientist’s Warning Odyssey) illustrates the difference that even one shy but determined person can make. I hope it inspires other individuals to take action before it’s too late.


World Scientists’ Warning of a Climate Emergency. In this video, Michael Mann and others explain how we can address the climate emergency through six steps: "(1) energy, eliminating fossil fuels and shifting to renewables; (2) short-lived air pollutants, slashing black carbon (soot), methane, and hydrofluorocarbons; (3) nature, restoring and permanently protecting Earth's ecosystems to store and accumulate carbon and restore biodiversity; (4) food, switching to mostly plant-based diets, reducing food waste, and improving cropping practices; (5) economy, moving from indefinite GDP growth and overconsumption by the wealthy to ecological economics and a circular economy, in which prices reflect the full environmental costs of goods and services; and (6) human population, stabilizing and gradually reducing the population by providing voluntary family planning and supporting education and rights for all girls and young women" (Ripple et al. 2021).

Our Hothouse Future? "Dr. Alison Green discusses the 1.5C controversy and ongoing climate emergency with Professor Bill McGuire, author and professor emeritus of geophysical and climate hazards at UCL." (see ScientistsWarning.TV for more videos)

Climate Leaders: Chris Rapley CBE "In this interview with Dr. Alison Green, Professor Chris Rapley CBE talks about his work as a leading climate scientist and explains why it is so important to understand the people factor in climate change (see ScientistsWarning.TV for more videos)

Prof Julia Steinberger, Ecological Economist, XR Activist, Anti-capitalist "Dr. Alison Green talks to Professor Julia Steinberger about the imminent challenges we face transforming the global economy away from its current deadly trajectory and from further climate chaos." (see ScientistsWarning.TV for more videos)

Social Media

For more AWS news, follow William Ripple on X (formerly Twitter).


To get in touch, please use our contact form.