The "World Scientists' Warning to Humanity" was a document written in 1992 by
Henry W. Kendall
Henry Way Kendall (December 9, 1926 – February 15, 1999) was an American particle physicist who won the Nobel Prize in Physics in 1990 jointly with Jerome Isaac Friedman and Richard E. Taylor "for their pioneering investigations concerning dee ...
and signed by about 1,700 leading scientists. Twenty-five years later, in November 2017, 15,364 scientists signed "World Scientists' Warning to Humanity: A Second Notice" written by
William J. Ripple and seven co-authors calling for, among other things,
human population planning
Human population planning is the practice of intentionally controlling the growth rate of a human population. The practice, traditionally referred to as population control, had historically been implemented mainly with the goal of increasing po ...
, and drastically diminishing
per capita
''Per capita'' is a Latin phrase literally meaning "by heads" or "for each head", and idiomatically used to mean "per person". The term is used in a wide variety of social sciences and statistical research contexts, including government statistic ...
consumption of
fossil fuels,
meat, and other
resources
Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their ...
. The second notice has more scientist cosigners and formal supporters than any other journal article ever published.
First publication
In late 1992, the late
Henry W. Kendall
Henry Way Kendall (December 9, 1926 – February 15, 1999) was an American particle physicist who won the Nobel Prize in Physics in 1990 jointly with Jerome Isaac Friedman and Richard E. Taylor "for their pioneering investigations concerning dee ...
, a former chair of the board of directors of the
Union of Concerned Scientists
The Union of Concerned Scientists (UCS) is a nonprofit science advocacy organization based in the United States. The UCS membership includes many private citizens in addition to professional scientists. Anne Kapuscinski, Professor of Environmenta ...
(UCS), wrote the first warning, "World Scientists' Warning to Humanity", which begins: "Human beings and the natural world are on a collision course." A majority of the
Nobel Prize
The Nobel Prizes ( ; sv, Nobelpriset ; no, Nobelprisen ) are five separate prizes that, according to Alfred Nobel's will of 1895, are awarded to "those who, during the preceding year, have conferred the greatest benefit to humankind." Alfre ...
laureates in the sciences signed the document; about 1,700 of the world's leading
scientists
A scientist is a person who conducts scientific research to advance knowledge in an area of the natural sciences.
In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophi ...
appended their signature.
It was sometimes offered in opposition to the
Heidelberg Appeal The ''Heidelberg Appeal'', authored by , was an appeal directed against the findings of the Intergovernmental Panel on Climate Change. Lawrence Powell, James: ''The Inquisition of Climate Science''. New York 2012, p. 56. The Heidelberg Appeal's goal ...
—also signed by numerous scientists and Nobel laureates earlier in 1992—which begins by criticizing "an irrational
ideology which is opposed to scientific and
industrial progress, and impedes economic and social development." This document was often cited by those who oppose theories relating to climate change.
In contrast, the UCS-led
petition
A petition is a request to do something, most commonly addressed to a government official or public entity. Petitions to a deity are a form of prayer called supplication.
In the colloquial sense, a petition is a document addressed to some offic ...
contains specific recommendations: "We must, for example, move away from
fossil fuels to more benign, inexhaustible
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...
sources to cut
greenhouse gas
A greenhouse gas (GHG or GhG) is a gas that absorbs and emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor (), carbon dioxide (), met ...
emissions and the
pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...
of our
air and
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
. ... We must stabilize population."
Second Notice
In November 2017, 15,364 scientists signed "World Scientists' Warning to Humanity: A Second Notice" written by lead author professor of ecology,
William J. Ripple of
Oregon State University
Oregon State University (OSU) is a Public university, public Land-grant university, land-grant, research university in Corvallis, Oregon. OSU offers more than 200 undergraduate-degree programs along with a variety of graduate and doctoral degree ...
, along with 7 co-authors calling for, among other things,
limiting population growth, and drastically diminishing
per capita
''Per capita'' is a Latin phrase literally meaning "by heads" or "for each head", and idiomatically used to mean "per person". The term is used in a wide variety of social sciences and statistical research contexts, including government statistic ...
consumption of
fossil fuels,
meat, and other
resources
Resource refers to all the materials available in our environment which are technologically accessible, economically feasible and culturally sustainable and help us to satisfy our needs and wants. Resources can broadly be classified upon their ...
. The second notice included 9 time-series graphs of key indicators, each correlated to a specific issue mentioned in the original 1992 warning, to show that most environmental issues are continuing to trend in the wrong direction, most with no discernible change in rate. The article included 13 specific steps humanity could take to transition to
sustainability
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livin ...
.
The second notice has more scientist cosigners and formal supporters than any other journal article ever published. The full warning was published in ''
BioScience
''BioScience'' is a monthly peer-reviewed scientific journal that is published by Oxford University Press on behalf of the American Institute of Biological Sciences. It was established in 1964 and was preceded by the ''AIBS Bulletin'' (1951–19 ...
'' and it can still be endorsed on the Scientists Warning website.
2019 warning on climate change and 2021 and 2022 updates
In November 2019, a group of more than 11,000 scientists from 153 countries named climate change an "emergency" that would lead to "untold human suffering" if no big shifts in action takes place:
The emergency declaration emphasized that
economic growth and
population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
"are among the most important drivers of increases in emissions from fossil fuel combustion" and that "we need bold and drastic transformations regarding economic and population policies".
A 2021 update to the 2019 climate emergency declaration focuses on 31 planetary vital signs (including greenhouse gases and temperature, rising sea levels, energy use, ice mass, ocean heat content, Amazon rainforest loss rate, etc), and recent changes to them. Of these, 18 are reaching critical levels. The
COVID-19 lockdowns
Due to the COVID-19 pandemic, a number of non-pharmaceutical interventions colloquially known as lockdowns (encompassing stay-at-home orders, curfews, quarantines, and similar societal restrictions) have been implemented in numerous count ...
, which reduced transportation and consumption levels, had very little impact on mitigating or reversing these trends. The authors say only profound changes in human behavior can meet these challenges and emphasize the need to move beyond the idea that global heating is a stand alone emergency, and is one facet of the worsening environmental crisis. This necessitates the need for transformational system changes and to focus on the root cause of these crises, the vast human
overexploitation
Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term ap ...
of the earth, rather than just addressing symptom relief. They point to six areas where fundamental changes need to be made:
(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, which has been proven to lower fertility rates.
At the 30th anniversary of the World Scientists' Warning to Humanity, a second update to the climate emergency declaration concluded that "We are now at '
code red' on planet Earth".
2022 warning on population
In October 2022, Eileen Crist, William J. Ripple,
Paul R. Ehrlich
Paul Ralph Ehrlich (born May 29, 1932) is an American biologist known for his warnings about the consequences of population growth and limited resources. He is the Bing Professor Emeritus of Population Studies of the Department of Biology of S ...
, William E. Rees, and Christopher Wolf all contributed to the ''Scientists' warning on population'', published by ''
Science of the Total Environment
''Science of the Total Environment'' is a weekly international peer-reviewed scientific journal covering environmental science. It was established in 1972 and is published by Elsevier. The editors-in-chief are Damià Barceló ( Consejo Superior de ...
'' as "part of the ongoing series of scientists' warning publications," to address the negative impacts of population size and growth on the climate and
biodiversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity' ...
, which they posit "continues to be ignored, sidestepped, or denied." It calls for two actions that, if heeded, will stop
population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
before the end of this century. Firstly, the authors issue a global appeal to all adults to have no more than one child as part of the transformative changes needed to mitigate both climate change and
biodiversity loss
Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, de ...
. Secondly, the warning urges policy-makers to "implement population policies with two key female empowerment components," primarily improving education for young women and girls and providing high-quality family-planning services to all. It emphasizes that "the combination of institutional support to plan one's child-bearing choices and educational attainment, including enhanced opportunity for higher education for women, yields immediate fertility declines." It also posits that a
sustainable human population, which according to environmental analysts is "one enjoying a modest, equitable middle-class standard of living on a planet retaining its biodiversity and with climate-related adversities minimized," is between 2 and 4 billion people.
The warning also advocates for combatting
poverty
Poverty is the state of having few material possessions or little income. Poverty can have diverse < ...
,
patriarchy
Patriarchy is a social system in which positions of dominance and privilege are primarily held by men. It is used, both as a technical anthropological term for families or clans controlled by the father or eldest male or group of males a ...
and
overconsumption
Overconsumption describes a situation where a consumer overuses their available goods and services to where they can't, or don't want to, replenish or reuse them. In microeconomics, this may be described as the point where the marginal cost o ...
by the affluent, and calls for a global wealth tax to be levied primarily against "wealthy nations, industries and people who have benefitted the most from humanity's massive-scale historical and contemporary use of fossil fuels" in order to expand "clean sanitation and water availability, food sovereignty, and electrification via renewables." It stresses that poverty alleviation must include the provision of basic public services, in particular healthcare and education.
Other scientists' warnings
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See also
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Animal–industrial complex
The term animal–industrial complex (AIC) refers to the systematic and institutionalized exploitation of animals. It includes every economic activity involving animals, such as the food industry (e.g., meat, dairy, poultry, apiculture), anima ...
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List of global issues
A global issue is a matter of public concern worldwide. This list of global issues presents problems or phenomena affecting people around the world, including but not limited to widespread social issues, economic issues, and environmental issues ...
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Anthropocene
The Anthropocene ( ) is a proposed geological epoch dating from the commencement of significant human impact on Earth's geology and ecosystems, including, but not limited to, anthropogenic climate change.
, neither the International Commission ...
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Climate crisis
''Climate crisis'' is a term describing global warming and climate change, and their impacts. The term and the alternative term ''climate emergency'' have been used to describe the threat of global warming to humanity (and their planet), and to ...
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Climate emergency declaration
A climate emergency declaration or ''declaring a climate emergency'' is an action taken by governments and scientists to acknowledge humanity is in a Climate crisis, climate emergency. The first such declaration was made by a local government in ...
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Defaunation
Defaunation is the global, local or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient e ...
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Effects of global warming
The effects of climate change impact the physical environment, ecosystems and human societies. The environmental effects of climate change are broad and far-reaching. They affect the water cycle, oceans, sea and land ice ( glaciers), sea l ...
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Extinction Rebellion
Extinction Rebellion (abbreviated as XR) is a global environmental movement, with the stated aim of using nonviolent civil disobedience to compel government action to avoid tipping points in the climate system, biodiversity loss, and the risk o ...
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Habitat loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
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Habitat protection
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Holocene extinction
The Holocene extinction, or Anthropocene extinction, is the ongoing extinction event during the Holocene epoch. The extinctions span numerous families of bacteria, fungi, plants, and animals, including mammals, birds, reptiles, amphibians, f ...
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Human impact on the environment
Human impact on the environment (or anthropogenic impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to fit the needs ...
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Human overpopulation
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
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Individual action on climate change
Individual action on climate change can include personal choices in many areas, such as diet, travel, household energy use, consumption of goods and services, and family size. Individuals can also engage in local and political advocacy around issu ...
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Plant-based diet
A plant-based diet is a diet consisting mostly or entirely of plant-based foods. Plant-based diets encompass a wide range of dietary patterns that contain low amounts of animal products and high amounts of plant products such as vegetables, fr ...
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Scientists for Future
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Scientists for Extinction Rebellion
References
Excerpts and notes
Citations
Bibliography
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External links
World Scientists Warning to Humanity(2017)
(1992)
(2001)
''ScientistsWarning.org''(2018-Present)
''ScientistsWarning.TV''(2014-Present)
Phys.org. April 8, 2019.
{{Vegetarianism
Climate change policy
Environmentalism
Political statements
1992 in the environment
Science activism
1992 documents
2017 in the environment
2017 documents