Biosphere Daily Earth Science Environment Repost

Cows, up to environmental mischief again

Over a decade ago, one of my daughters announced she would no longer eat beef. I wrongly assumed this rash decision was made for health reasons since the U.K. mad-cow crisis was in full swing. However, while CJD was looming heavily on many minds, hers was not one of them. Environmental considerations were the impetus for her diet change because Brazilian beef farmers were burning away the rain forests to make more room for cattle ranching. Since then, cows have continued to engage in environmental mischief. Most recently, they were identified as the culprits responsible for draining our rivers dry.

The world loves its bovine friends, particularly when then are served medium rare on a dinner plate. Good beef is almost a luxury item judging by grocery store prices for choice-cut steaks. But the laws of supply and demand operate everywhere, and demand for beef keeps constant pressure on the supplies.

The world consumed 61 million metric tons of beef in 2018, with the U.S. accounting for 21 percent of that demand. Beef production worldwide has more than doubled since 1960. However, the U.S. beef cattle head-count fell from 45 million in the early 1970s to 31 million in 2020. High demand and falling supplies make for higher prices.

But cows come in more than just the beef variety, and the worldwide cattle head-count is currently about 1.4 billion. But, what kind of environmental mischief can over a billion cows get up to other than removing rain forests from a much-needed carbon sequestration inventory?


The average cow produces between 70 to 120 kilograms of methane each year from rumination (their digestive process), leading to over 100 million metric tons of methane released into the atmosphere annually. This contribution accounts for roughly one-third of the total annual methane from Anthropogenic (human) sources, and about 20 percent of all methane from combined natural and human sources.   

Methane is a powerful enabler of climate change since it is a “super greenhouse gas.” Over long periods it is 80 times more potent than carbon dioxide. 

Eating the rivers dry

The latest reported scandal concerning these four-legged environmental mischief-makers involves their proclivity for intense water usage. A recent article in Nature documented that irrigation of feed crops for cattle is the largest consumer of water from rivers in the American West. Some calculations estimate that a quarter-pound burger takes over 400 gallons of water.

Water in the western USA is an increasingly scarce commodity and thus serious business. The Colorado River provides water for some 40 million people. Also, it provides irrigation for 5.5 million acres. But the demands on this river now exceed its annual flow capacity. From 1999 – 2004, Lakes Powell and Mead on the Colorado River (two of the USA’s largest reservoirs) lost half their water. Cows are estimated to account for 75% of that missing water.

The American West is in a 20-year-long megadrought. The vital Ogallala aquifer is drying up from overuse, and water regulators struggle to keep up due to outdated water-use policy. However, a reckoning is coming that may pit our beloved burgers and steaks against major cities’ water needs. Given the politics involved, the cows may come out as winners in this battle and be left to continue with their environmental mischief.


The Colorado River is running dry (Source: ArcheanWeb) –  Also:

Ogallala Aquifer groundwater, sustaining life (Source: ArcheanWeb) – Also:

Hot and dry in the Western USA, a megadrought in progress (Source: ArcheanWeb) –  Also:


US rivers and lakes are shrinking for a surprising reason: cows (By Troy Farah; The Guardian) –  Also:

World Beef Consumption: Ranking Of Countries (By Rob Cook; Beef2Live) –  Also:

Beef Cows inventory (Source: USDA) –  Also:

Methane, explained (By ALEJANDRA BORUNDA; National Geographic) –  Also:

Methane Tracker 2020 (Source: IEA) –  Also:

Water scarcity and fish imperilment driven by beef production (By Brian D. Richter, Dominique Bartak, Peter Caldwell, Kyle Frankel Davis, Peter Debaere, Arjen Y. Hoekstra, Tianshu Li, Landon Marston, Ryan McManamay, Mesfin M. Mekonnen, Benjamin L. Ruddell, Richard R. Rushforth1 and Tara J. Troy; Nature) –   Also:

Feature Image: Cow (Modified) – By Daniel Schwen, CC BY-SA 3.0,  

William House
William is an earth scientist and writer with an interest in providing the science "backstory" for breaking environmental, earth science, and climate change news.