by Richard H. Schwartz
First, it is important to recognize that the world is rapidly heading toward an unprecedented catastrophe from global climate change and other environmental threats. There are almost weekly reports of severe droughts, heat waves, storms, flooding, wildfires and meltings of polar icecaps and glaciers.  While these events have occurred due to an average temperature increase of less than 1.5 degrees Fahrenheit in the past 100 years, global climate scientists, including those with the Nobel Prize-winning UN Intergovernmental Panel on Climate Change (IPCC), are projecting an increase of from 3 to 11 degrees Fahrenheit in the next 100 years , which would have devastating effects on humanity and all of life on the planet.
And we are talking about threats that must be addressed very soon. Some climate scientists, including James Hansen, director of the National Aeronautics and Space Administration (NASA) Goddard Institute for Space Studies, are warning that global warming could reach a tipping point and spin out of control within a few years, with disastrous consequences, unless major changes soon occur.  Scientists at the February, 2009 annual meeting of the American Association for the Advancement of Science indicated that global warming will likely increase more rapidly than expected because greenhouse gas emissions (GHGs) have increased faster than recent predictions and increased temperatures are setting off positive feedback (self-reinforcing) mechanisms in global ecosystems. 
There is increasing awareness of the need to make major changes in many phases of society to reduce global climate change. However, most lists of recommendations ignore or give little attention to the impact of our diets on GHGs. A landmark 2006 report by the United Nations Food and Agricultural Organization estimated that livestock production globally is responsible for more GHGs (in CO2 equivalents) than the world’s entire transportation sector combined (18 percent of worldwide anthropogenic GHGs for livestock vs. 13.5 percent for transportation).  The report, “Livestock’s Long Shadow,” also projects that the world’s current population of about 60 billion farmed animals will double in 50 years if human population growth and dietary trends continue.  The resulting increase in GHGs would largely negate reduced GHG emissions from improved efficiencies in transportation, electricity and other sectors and conservation steps, and make it extremely difficult, if not impossible, to reach the GHG reductions that climate experts think are essential to avoid a climate disaster.
Expert recognition of the importance of diet in preventing global warming is growing. In the Fall of 2008, Dr. Rajendra Pachauri, Chair of the IPCC, which shared a Nobel Peace Prize with Al Gore in 2008, called on people in the developed world to “give up meat for one day [a week] initially, and decrease [meat consumption] from there.”  More recently, James Hansen, perhaps the most prominent scientific advocate of aggressive action against global warming — told an interviewer:
“… if you eat further down on the food chain rather than animals, which have produced many greenhouse gases, and used much energy in the process of growing that meat, you can actually make a bigger contribution in that way than just about anything. So, that, in terms of individual action, is perhaps the best thing you can do.” 
The main reason that animal agriculture’s contribution is so great is that farmed animals, especially cattle and other ruminants, emit methane as part of their digestive processes (belching and farting) and methane is about 23 times as potent as CO2 in producing global warming, when standard 100 year periods are considered.  However, since most methane survives in the atmosphere for less than 20 years, if a 20 year period is considered, methane is about 72 times as potent as CO2.  By contrast, CO2 is in the atmosphere for hundreds of years and its impact is reduced by the predominantly cooling aerosols emitted by typical CO2 sources like smokestacks and tailpipes. 
Since methane contributes a significant amount of GHGs (in CO2 equivalents)  and since farmed animals and their manure are by far the major source of methane, and since methane is in the atmosphere for only a short time, a major societal shift to plant-based diets would have a substantial and very rapid effect in reducing global climate change. Having major world leaders call for such a change, preferably after publicly announcing suitable changes in their own diets, could very dramatically increase awareness of the threats of global warming and the need for major dietary and other lifestyle changes. Such changes could provide some breathing space, during which other important changes could be made.
Additional factors that make switches to plant-based diets even more important are: (1) the production of animal products causes about nine percent of total CO2 emissions, from the production of pesticides and fertilizer, use of irrigation pumps, extensive refrigeration and other processes;  (2) nitrous oxides are emitted from animals’ manure and from chemical fertilizer used to grow feed crops and these gases are almost 300 times as potent as CO2 in producing warming;  (3) the burning of rainforests to create grazing land and land to grow feed crops for animals also releases substantial CO2 and also destroys trees that would absorb CO2;  (4) because they feast on the charred remains of these trees, termites are perhaps the fastest growing animal species on the planet, and they also emit methane as part of their digestive processes.  Taking all of the above factors into account, the UN FAO estimate that animal agriculture emits 18 percent of anthropogenic GHGs (in CO2 equivalents) is arguably significantly lower than the true number, as incredible as the 18 percent value is when one considers all the cars, trucks, buses, planes, ships and other means of transportation worldwide.
Major shifts to vegan diets would also provide substantial relief to many other threats to humanity:
The dietary connection is that it takes up to 14 times as much water per person for a typical animal-based diet than for a vegan diet.  The amount of water necessary to raise one steer to maturity would float a naval destroyer.  Also, as indicated above, animal-based agriculture contributes significantly to global warming which contributes to droughts and to the melting of glaciers and the reduced flow of rivers and streams and levels of lakes and ponds.
1. See, for example, “Climate Change, Global risks, challenges & decisions,” Copenhagen 10-12 March, 2009, University of Copenhagen, Denmark, http://lyceum.anu.edu.au/wp-content/blogs/3/uploads//Synthesis%20Report%20Web.pdf
2. “Intergovernmental Panel on Climate Change (IPCC) Fourth
Assessment Report,” February, 2007. http://www.ipcc.ch/
3. James Hansen, “Tipping Point: Perspective of a Climatologist,” 2008=2009 State of the World, 6,
4. American Association for the Advancement of Science, February, 2009 annual conference, Public release, “Climate change likely to be more devastating than experts predicted, warns top IPCC scientist,”
5. FAO Newsroom, “Livestock a major threat to environment,” November 29. 2006,
7. Juliette Jowitt, “UN says eat less meat to curb global warming,” The Observer, September 7, 2008, http://www.guardian.co.uk/environment/2008/sep/07/food.foodanddrink
8. Be Veg! Go Green! Save the Planet, February 8, 2008, “Dr. James Hansen: “We have only four years left to act on climate change,” http://veg4planet.blogspot.com/2009/02/dr-james-hansenwe-have-only-four-years.html
9. Noam Mohr, “A New Global Warming Strategy:
How Environmentalists are Overlooking Vegetarianism as the Most Effective Tool Against Climate Change in Our Lifetimes,” Earthsave,
10. Supreme Master TV Video, “Methane __ 72 Times the Warming Potential of CO2,” June, 2009,
11. Same as #9
3. UN News Centre Report, “Rearing cattle produces more greenhouse gases than driving cars, UN report warns, http://www.un.org/apps/news/story.asp?NewsID=20772&Cr=global&Cr1=environment
15. “Burning rainforests, melting tundra could accelerate global warming well beyond current projections.” mongabay.com, February 16, 2009
16. Greg Brockberg, “Termites as a Source of Atmospheric Methane,” http://www.iitap.iastate.edu/gcp/studentpapers/1996/atmoschem/brockberg.html
17. UN FAO Report, “1.02 billion people hungry; one sixth of humanity malnourished – more than ever before.” June 19, 2009, http://www.fao.org/news/story/en/item/20568/icode/
18. “Our Food, Our World,” Earthsave Foundation, 1992, p.6.
19. ”Eating up the World: the Environmental Consequences of Human Food Choices,” 16 page booklet, Vegetarian Network Victoria, 2009,
20. GoVeg.com, “Wasted Resources – Food,”
21. Paul Kedrosky, “Lester Brown on the Coming Food Crisis (Again), Infectious Greed, May 20, 2009, http://paul.kedrosky.com/archives/2009/05/lester_brown_on.html
22. Dan Vergano, “Water shortages will leave world in dire straits,” USA Today, January 26, 2003,
23. Michael McCarthy, “The Century of Drought
One third of the planet will be desert by the year 2100, say climate experts in the most dire warning yet of the effects of global warming,” CommonDreams.org, October 4, 2006,
24. Brad Johnson, The Wonk Room, “”Global Boiling: In California It’s ‘Fire Season All Year Round,’”
25. Kristin Underwood, “Australia’s Drought Worsens,” Treehugger, February 9, 2008,
Also: “Report: Climate Change 2009 – Faster Change and More Serious Risks,” Australian Government Department of Climate Change, July 9, 2009,
26. Jewish Telegraphic Agency Report, “Israel halts Sea of Galilee water pumping, January 22, 2009, http://jta.org/news/article/2009/01/22/1002430/israel-halts-sea-of-galilee-water-pumping
27. Tell Youth the Truth, “Animal Agriculture Equates to Wasted Resources and environmental Degradation,”
28. “The Browning of America,: Newsweek, February 22, 1981, p. 26.
29. John Timmer, ars technia, “Ex-military leaders call climate change a national security issue,” May 28, 2007, http://arstechnica.com/news.ars/post/20070528-ex-military-leaders-call-climate-change-a-national-security-issue.html
30. Jacl Burton, “Climate Change as Catalyst for War: Can We Stop the World’s Water Crisis or Is Darfur Only the Beginning,” Suite 101.com,February 11, 2008,
31. Crede Calhound, “Kids Can Help Save the Rainforest,”
32. John Roach, “Seafood May Be Gone by 2048, Study Says,” National Geographic News, November 2, 2006,
Richard H. Schwartz
Professor Emeritus, College of Staten Island
Author of Judaism and Vegetarianism, Judaism and Global Survival and Mathematics and Global Survivaland over 140 articles at JewishVeg.com/schwartz
President. Jewish Vegetarians of North America (www.JewishVeg.com); Director of Veg Climate Alliance
Associate producer of A SACRED DUTY