Richard H. Schwartz
Vegan, climate change,and social justice activist

 Pikuach Nefesh, Climate Change, and Human Survival

Judaism stresses pikuach nefesh, the principle that everything possible must be done to save a life, even if Jewish law has to be violated to do so. Of the 613 Torah mitzvot (commandments), 610 of them can be violated if if it might help save a life. The three exceptions are the prohibitions against murder, idolatry, and sexual immorality, the three cardinal sins.

The Torah teaches that humans were created, “in God’s image,” (Genesis 1:26, 5:1), and, therefore, each person is of infinite value. A famous Mishnah reinforces this teaching: “Therefore, man was created as an individual, to teach that one who kills another person it is as if he destroys an entire world and one who saves another person, it is as if he saves an entire world.” (Sanhedrin, 4:5)

Judaism requires that major precautions be taken to reduce risks to human life. An example is that a new house’s roof must have a protective parapet to prevent people from falling (Deuteronomy 22:8). Based on this teaching, the revered Jewish philosopher Maimonides generalizes: “for any case where there’s a danger that a person may unwittingly die from … there is a positive obligation to remove the danger and to be extremely careful about it … and if one neglects to do so and leaves impediments that can cause danger he has negated a positive commandment and violated “that thou bring not blood upon thine house.” (Maimonides, Hilkhot Rotzeah V’shemirat Nefesh. 11:4)

Another example of the Jewish responsibility to speak out against evil is in the Talmud (Shabbat 54b):

“Whoever is able to protest against the transgressions of his own family and does not do so is punished for the transgressions of his family. Whoever is able to protest against the transgressions of the people of his community and does not do so is punished for the transgressions of his community. Whoever is able to protest against the transgressions of the entire world and does not do so is punished for the transgressions of the entire world.”

Today, it is more urgent than ever before that the important Jewish principle of pikuach nefesh be applied in response to climate threats, because it is not just one life that is threatened, but potentially the lives of all of the nearly eight billion people on Earth.

Is this an outrageous exaggeration, like past predictions of an end to the world? Not according to science academies worldwide, 97% of climate scientists, and virtually all peer-reviewed papers on the issue in respected scientific journals, that argue that climate change is largely caused by human activity and poses a great threat to humanity. All the leaders of the 195 nations at the December 2015 Paris Climate Change Conference, including Israel and the US, agreed that immediate steps must be taken to avert a climate catastrophe, and most of the nations pledged to significantly reduce their greenhouse-gas emissions. While this is an important step forward, climate experts believe that even if, and it is a very big if, all the pledges are kept, they would not be enough to prevent future severe climate disruptions.

An October 2018 report by the respected Intergovernmental Panel on Climate Change (IPCC), an organization composed of leading climate experts from many countries, warned that the world may have only until 2030 to make “unprecedented changes” in order to avert far more severe climate events..

The world is already seeing many devastating effects of climate change. Contrary to the views of many climate-change deniers, the world’s average temperature has significantly increased in recent years. Every decade since the 1970s has been hotter than the previous decade, and each of the 21 years in this century are among the 22 hottest years since temperature records worldwide started being kept in 1880. With June and July 2021 being the hottest for these months, this year  is on track for possibly being the hottest year, after 2020 tied 2016 as the previous hottest one.

Just as a person with a high fever suffers from many of its effects, there have been many negative effects of increased global temperature. Polar icecaps, glaciers worldwide, and permafrost have been melting rapidly, faster than scientific projections. Unprecedented rainfall in parts of Greenland has caused extremely rapid rmelting. This has caused an increase in ocean levels worldwide with the potential for major flooding. Already there is “sunny day” flooding due to hight tides in Miami, Florida, and other coastal cities. Glaciers are “reservoirs in the sky,” providing important water for irrigating crops every spring, so their retreat will be a major threat to future food supplies for an increasing world population.

There has also been an increase in the number and severity of droughts, wildfires, storms and floods. As I write this on September 1, 2021, just in the past few weeks there have been major, sometimes unprecedented, wildfires in many places, including California, Greece, and even Siberia, deadly floods in western Europe, India, and China.

Hurricane Ida slammed into Louisiana as a category four storm, causing much devastation in US Gulf States, and was so powerful that it also caused massive, unprecedented flooding over a thousand miles away, in New York and New Jersey, completely shutting down the much-depended-on New York City subway system.

Of course, there have always been such climate events, but climate change has made them far more frequent and destructive. 

On September 1, 2021, the World Meteorological Organization reported that severe climate events due to climate change have increased fivefold over the past 50 years, killing over 50 million people, and costing total losses of $3.64 trillion.

There are three climate-related factors that increase the severity of hurricanes:

• More moisture evaporates as temperatures increase and warmer air holds more moisture, increasing risks for flooding during storms.

• As indicated before, seas have risen, which increases storm surges.

  • Ocean waters are warmer, which adds more energy to storms.

Also, the hotter, drier weather makes wildfires more frequent and destructive.

California has been subjected to so many severe climate events recently that its former governor, Jerry Brown, stated, “Humanity is on a collision course with nature.”

Unfortunately, prospects for the future are truly terrifying. The severe climate events mentioned above occurred due to a temperature increase of about 1.1 degrees Celsius (about two degrees Fahrenheit) since the start of the industrial revolution, but climate experts are predicting at least a tripling of that temperature increase by the end of the century, which would greatly increase the destructiveness of climate events., 

Also, climate experts believe that the world may be close to a tipping point wherein climate change will spin out of control, with disastrous consequences, unless major positive changes soon occur. The potential for such a tipping point is increased because of self-reinforcing positive climate feedback loops (vicious cycles). For example, when there are major wildfires, trees, which absorb and store CO2, are destroyed, much carbon from the burning trees is released into the atmosphere, and additional energy will be required to replace destroyed cars, homes, and other structures, increasing the potential for additional, and even more potent, future climate events.           

Another example is that when ice, a very good reflector of the sun’s rays, melts, the darker soil or water that is revealed absorbs much more of the sun’s energy, causing more ice to melt, starting a potentially very damaging vicious cycle.

Another alarming factor is, while climate experts believe that 350 parts per million (ppm) of atmospheric CO2 is a threshold value for climate stability, the world has now reached 420 ppm, the highest value in human history, and the CO2 level is continuing to increase. Another major negative factor is the warning by the Pentagon and other military groups that climate change will increase the potential for instability, terrorism and war, by reducing access to food and clean water, and by causing tens of millions of desperate refugees to flee from droughts, wildfire, floods, storms, and other effects of climate change. Already there have been civil wars in the Sudan and Syria after farms failed after extensive droughts, and desperate farmers moved into already overcrowded cities, causing unrest and rebellion to occur. 

An IPCC Report in early August 2021 was especially alarming with regard to the future of climate change. UN Secretary-General António Guterres called it “a code red for humanity,” adding:“The alarm bells are deafening, and the evidence is irrefutable” that the world is heading rapidly toward a climate catastrophe.

Reducing climate change is especially important for Israel, as a rising Mediterranean Sea could inundate the coastal plain where much of Israel’s population and infrastructure are located, and the increasingly hotter and drier Middle East that climate experts are projecting also makes terrorism and war in the region more likely. There have been recent articles in the Jewish media with very frightening headlines, such as “Will Israel become uninhabitable?”

In view of the above, involving the potential massive loss of lives, the concept of pikuach nefesh is definitely a consideration, so Jews, tasked with being “a light unto the nations,” should be leading efforts to avert  a climate catastrophe, in order to secure a sustainable, livable world for future generations. Every aspect of life should be considered. The world has to shift to renewable forms of energy, improve our transportation systems, produce more efficient cars and other means of transportation, reduce population growth, decrease deforestation and increase forestation, and do everything else possible to reduce greenhouse gas emissions.

As president emeritus of Jewish Veg, formerly Jewish Vegetarians of North America, I want to stress the generally unknown or disregarded importance of shifts toward vegetarian and vegan diets. Animal-based agriculture is a major contributor to climate change, largely due to the emission of methane from cows and other farmed animals, since methane is from 72 to 105 times as potent as CO2 per unit weight in warming the atmosphere during the 20 years that the gas is in the atmosphere.

Two studies support this conclusion:

• As long ago as 2006, a UN Food and Agriculture Organization study, “Livestock’s Long Shadow,” found that livestock agriculture emitted more greenhouse gases in CO2 equivalents than all the cars, planes, ships and other means of transportation worldwide combined.

  • A 2009 cover story in World Watch magazine, “Livestock and Climate Change,” by two environmentalists associated with the World Bank, found that the livestock sector was responsible for at least 51% of all human-induced GHGs.

What very significantly distinguishes dietary changes from other positive changes is that not only would greenhouse gas emissions from cows and other animals be reduced, but the freeing of much of the over a third of the world’s ice-free areas that are currently used to graze and raise feed crops for animals could be filled with trees and other plants, permitting the absorption of much atmospheric CO2. This would have a net effect of reducing atmospheric greenhouse gases by 51 to at least 87 percent, returning it to safe levels, sharply reducing extreme weather events, making dietary changes the best and possibly the only way to avert a climate catastrophe.

There are at least three additional reasons why shifts to vegan diets involve pikuach nefesh, because of the many lives that would be saved as a result:

  1. Animal-based diets contribute significantly to heart disease, several forms of cancer, and other life-threatening diseases. Many peer-reviewed studies in respected medical journals have shown that vegan diets can not only reduce risks for such diseases, but in some cases can reverse them.
  2. The widespread mistreatment of farmed animals and sometime wild animals for human consumption makes future pandemics, with their life-threatening consequences, more likely. Many previous pandemics, including MERS, SARS, Ebola, swine flu, and bird flu, and possibly the current Coronavirus pandemic, were connected to animal abuses. 
  3. While an estimated nine million people die from hunger and its effects worldwide annually and over ten percent of the world’s people are chronically malnourished, about 70  percent of the grain produced in the US and over a third produced worldwide are used to fatten farmed animals. Making the situation even more shameful, healthy foods, like corn, oats, and soy, high in fiber and complex carbohydrates and devoid of cholesterol and saturated fat are fed to animals, resulting in unhealthy foods, with the opposite characteristics.

In summary, to best fulfill the Jewish important principle of pikuach nefesh, Jews should be leaders in efforts to avert a climate catastrophe and, to further that aim and for the other reasons mentioned above, they should adopt vegan diets or at least sharply cut their consumption of meat and other animal products. By changing their diets and increasing awareness of the importance of others also doing so, Jews will help shift our imperiled planet onto a sustainable path. They would also be acting consistently with basic Jewish teachings on preserving our health, treating animals with compassion, protecting the environment, conserving natural resources, helping hungry people, and pursuing peace, thereby helping to revitalize Judaism.

About the Author
Richard H. Schwartz, Ph.D., is the author of Judaism and Vegetarianism, Judaism and Global Survival, Who Stole My Religion? Revitalizing Judaism and Applying Jewish Values to Help Heal our Imperiled Planet, and Mathematics and Global Survival, and over 200 articles and 25 podcasts at He is President Emeritus of Jewish Vegetarians of North America (JVNA) and President of the Society of Ethical and Religious Vegetarians (SERV). He is associate producer of the 2007 documentary “A Sacred Duty: Applying Jewish Values to Help Heal the World.” He is also a Professor Emeritus of Mathematics at the College of Staten Island, which is part of the City University of New York.
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