Thou shalt not eat meat? Have I gone completely crazy? Am I not aware that the Torah gives people permission to eat meat and goes into detail in discussing which animals are permitted to be eaten and which are not? And that the Talmud has much material on the laws of kashrut related to the preparation and consumption of meat? And that various types of flesh products have been strongly associated with Sabbath and festival celebrations?

Yes, but I still think that it is necessary, actually essential, to argue this case because our modern meat-centered dietary culture is doing great harm to Jews, Israel and, indeed, the entire world and is inconsistent with several important Jewish values.

The world is rapidly approaching an unprecedented catastrophe from global warming and other environmental threats, to which animal-based agriculture is a major contributor. Pikuach nefesh (the mandate to do whatever is necessary to save a human life) is arguably Judaism's most important mitzvah, because it overrides all other mitzvot, except those forbidding murder, idol worship and sexual immorality, which are not applicable to the issues under consideration. It is especially important today that we pay attention to this mandate because we are dealing with the possibility of saving not just one life, but all of humanity.

Please consider:

* There are almost daily reports of the effects of global climate change, including severe heat waves, storms, droughts, floods  and wildfires, and the melting of glaciers and polar icecaps.

* While these effects are due to an increase of less than 1.5 degrees Fahrenheit in the past 100 years, the Intergovernmental Panel on Climate Change (IPCC), a group composed of the world's leading climate scientists, projects an increase of from 3 to 11 degrees Fahrenheit in the next 100 years, which would result in an unparalleled disaster for humanity..

* Some climate scientists, including James Hansen of NASA, are warning that global climate change may spin out of control within a few years with extreme consequences, unless major changes are soon made.

* Israel is especially threatened by global warming. It is now experiencing the worst drought in its history, and the reduced rainfall the last few years has so diminished the level of the Sea of Galilee that the pumping of water from it had to be stopped. In 2007 a report by the Israel Union for Environmental Defense projected that if current trends continue, Israel will experience major heat waves, storms and floods, a decrease in average rainfall of 20 to 30 percent and an inundation of the coastal plain where most Israelis live by a rising Mediterranean Sea.

* According to a 2006 UN Food and Agriculture Organization report, animal-based agriculture emits more greenhouse gases than all the cars, ships, planes and other means of transportation combined (18% in CO2 equivalents vs. 13.5%, and some reports indicate that the gap is even greater), and this difference will sharply increase because the number of farmed animals is projected to double in 50 years, if present trends continue. Hence, without a major societal shift to plant-based diets, it will be impossible to obtain the greenhouse gas emissions that climate experts think are essential to avoid the worst effects of global warming.

* Animal-centered agriculture also causes other serious environmental problems, including soil erosion and depletion, the rapid extinction of species, air and water pollution, and the destruction of tropical rain forests, coral reefs and other valuable habitats. An animal-based diet requires up to 14 times as much water as a vegan diet.

The many negative effects of animal-based diets was well summed up by the editors of World watch magazine in their July/August 2004 issue: "The human appetite for animal flesh is a driving force behind virtually every major category of environmental damage now threatening the human future. Deforestation, erosion, fresh water scarcity, air and water pollution, climate change, biodiversity loss, social injustice, the destabilization of communities, and the spread of disease."

We have recently seen an example of that “spread of disease” as the close confinement of many farmed animals in very unsanitary conditions has resulted in a pandemic of swine flu, the latest example of diseases resulting from the massive factory farming of animals.

A second major reason that Jews should avoid eating meat is that high meat consumption and the ways in which meat is produced today conflict with at least six basic Jewish teachings:

1) While Judaism mandates that people should be very careful about preserving their health and their lives, numerous scientific studies have linked animal-based diets directly to heart disease, stroke, many forms of cancer, and other chronic degenerative diseases.

2) While Judaism forbids tsa'ar ba'alei chayim, inflicting unnecessary pain on animals, most farm animals -- including those raised for kosher consumers -- are raised on "factory farms" where they live in cramped, confined spaces, and are often drugged, mutilated, and denied fresh air, sunlight, exercise, and any enjoyment of life, before they are slaughtered and eaten.

3) While Judaism teaches that "the earth is the Lord's" (Psalm 24:1) and that we are to be God's partners and co-workers in preserving the world, modern intensive livestock agriculture contributes substantially to soil erosion and depletion, air and water pollution, overuse of chemical fertilizers and pesticides, the destruction of tropical rain forests and other habitats, global warming, and other environmental damage.

4) While Judaism mandates bal tashchit, that we are not to waste or unnecessarily destroy anything of value, and that we are not to use more than is needed to accomplish a purpose, animal agriculture requires the wasteful use of grain, land, water, energy, and other resources.

5) While Judaism stresses that we are to assist the poor and share our bread with hungry people, over 70% of the grain grown in the United States is fed to animals destined for slaughter, while an estimated 20 million people worldwide die because of hunger and its effects each year.

6) While Judaism stresses that we must seek and pursue peace and that violence results from unjust conditions, animal-centered diets, by wasting valuable resources, help to perpetuate the widespread hunger and poverty that eventually lead to instability and war.

We could say "dayenu" after each of the arguments above, because each constitutes by itself a serious conflict between Jewish values and current practice that should impel Jews to seriously consider a plant-based diet. Combined, they make an urgently compelling case for the Jewish community to address these issues.

This view is reinforced by some statements by Rabbi David Rosen, former Chief Rabbi of Ireland. He believes that even if eating meat is considered a mitzvah, which he doesn't, it would be a mitzvah haba'ah b'aveirah (a mitzvah based on transgressions). He asserts that “the current treatment of animals in the livestock trade definitely renders the consumption of meat as halachically unacceptable as the product of illegitimate means,” and that “as it is halachically prohibited to harm oneself and as healthy, nutritious vegetarian alternatives are readily available, meat consumption has become halachically unjustifiable.”

Finally, the view that Jews should not eat meat is reinforced by an extension of an article, “Thou Shalt Not Smoke,” by Rabbi Abraham J. Twerski, an Orthodox psychiatrist, scholar and author. His strong arguments based on health reasons are also applicable to eating meat and, as indicated above, there are many additional reasons for not eating meat.

Rabbi Twerski concludes, “Cigarette smoking causes disease and death. 'Those who have the capacity to eliminate a wrong and do not do so bear the responsibility for its consequences.' [His emphasis.] These are harsh words, but they are not mine. They are the words of the Talmud, Tractate Shabbos 54b.” Since the eating of meat not only “causes disease and death,” but also greatly harms billions of animals, contributes significantly to global warming and many other environmental threats, uses water, energy, land and other resources very inefficiently and contributes to widespread hunger, his conclusion is even more applicable to the consumption of meat.

For many years I have argued that Jews have a choice in their diets, but that choice should consider the negative effects of animal-based diets on Jewish teachings, such as those mentioned above. Unfortunately, this has had less impact than I would like, as the world moves increasingly toward a catastrophe beyond anything since the great flood in the time of Noah. Hence, while it may initially seem very foreign to many Jews, I think it is consistent with Judaism and essential to argue that “Thou shalt not eat meat.” Taking this assertion seriously and acting upon it is essential to moving our imperiled planet to a sustainable path.