The headline read: “With Latest $350 Million Gift to Johns Hopkins, Bloomberg Surpasses $1 Billion in Giving to Alma Mater.”

The alma mater being Johns Hopkins University in Baltimore, and the gift-giver being billionaire and New York City Mayor Michael Bloomberg.

This latest gift brings Mr. Mayor’s total giving to the university to $1 billion, with a “b.”

That total includes:

  • $250 million to facilitate cross-disciplinary work across the university
  • Funding to endow 50 Bloomberg Distinguished Professorships in areas such as water resource sustainability, individualized healthcare delivery, global health, the science of learning, and urban revitalization
  • $100 million to provide Bloomberg Scholarships to 2,600 undergrads over the next 10 years, so that, as a news release from the Philanthrophy News Digest phrased it, “The most talented and driven students can attend the university, regardless of economic circumstance.”

Bloomberg, who earned his bachelor's degree in engineering from the university in 1964, made his first gift—a $5 donation—to the school in 1965. Since then, he’s been a devoted supporter of the university, contributing a total of $336 million in support of research projects, $289 million to the Bloomberg School of Public Health, $240 million for various capital and infrastructure projects and $219 million in support of need-based financial aid.

The majority of Hizzoner’s latest gift—about $250 million—will support the appointment of faculty in the areas of water resource sustainability, individualized health care delivery, global health, the science of learning and urban revitalization, according to news reports.

Did you notice that first item? Water resource sustainability? That’s a problem, because that’s directly tied to the ongoing accusationthat raising livestock is the prime suspect in wasting water. In fact, the Humane Society of the United States, PETA and various other anti-industry activist groups have been working in concert for years to keep pounding way at a specific stat: That each pound of beef requires 2,500 gallons of water to produce.

Just Google the phrase “water use in beef,” and you’ll immediately be hit with that figure: “The most reliable and widely accepted water estimate to produce beef . . . is the figure of 2,500 gallons a pound,” is how the assertion is typically phrased. Some sources claim that the figure is even higher.

Bad arithmetic

There are several problems with that stat.

First, it’s inaccurate, even according to the proponents of the “eat-less-meat-and-switch-to-vegetarian foods” positioning., the source most widely cited, has a lengthy explanation of the “virtual water” contained in food designed to guilt-trip people into giving up animal foods. However, after 10 minutes of trying to wade through endless calculations estimating liters of water used per kilogram of beef (and talk about deceptive—their math is based on boneless beef, or 440 pounds of beef from a three-year-old steer), the final figure turns out to be 1,866 gallons, not 2,500. That may not seem like a big deal, but it’s a 25 percent reduction from the figure activists love to toss out.

Second, as any eighth-grade kid can explain, water is largely recycled. The water used in processing, for example, isn’t “used up,” it’s sent back to some sort of treatment plant to be eventually returned to the same sources from which it came: Lakes, rivers, and reservoirs.

That factoid is never mentioned in the scare stories about wasting water on animal agriculture, however.

Finally, and more importantly, even the “adjusted” figure isn’t really plausible. Several federal agencies have calculated that the average U.S. residential household uses an acre-foot of water a year, which is 325,000 gallons. If you break out the calculator, that means the 100 million + U.S. households would “consume” about 32 trillion gallons of water a year.

Now, if we take at face value the figure of 2,500 gallons of water per pound of boneless beef, then using USDA figures, there was an average of about 13 billion pounds of boneless beef produced last year. Using that number, guess what beef’s total water footprint is?

About 32 trillion gallons of water a year.

In other words, activists would have us believe that the production of beef alone—not counting pork, chicken or turkey—consumes as much water as the entire U.S. residential population.

Does that feel right?

Not in the least.

But you can bet that plenty of that $250 million that Mayor Bloomberg just handed over to Johns Hopkins University School of Public Health will be invested in even more computer modeling to bolster the idea that Meatless Mondays is the single most important action consumers should take to solve the world’s water shortages.

That’s wrong on so many levels—especially the mathematical one.

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.