The Colorado River and those who depend on it are in trouble. A once-in-a-millennium drought now entering its third decade is shrinking water levels to disturbing numbers. The seven states and Mexico that rely on the Colorado are worried. As we should be. Two of the states, California and Arizona, produce many of the fruits and vegetables we take for granted. The farms that it supplies feed hundreds of millions of people, throughout North America, including Canadians. Seventy percent of the water used is for agriculture.

The states that rely on it have shared the water under historic agreements, but now there isn’t enough to meet the demands. The federal government is stepping in and has announced urgently required cutbacks. There will be some unhappy states and no doubt tension between cities and farmers.

As I read about the crisis, one statistic jumped out at me. About half of the water is used to grow animal feed, largely alfalfa, a very thirsty crop. And most of that goes to feed cows. It occurred to me that if we were all vegetarians, there would be no water shortage on the Colorado. There would be lots of water for everybody.

Everyone knows by now that supplying ourselves with protein via meat is ridiculously inefficient. It takes about 25 kilos of plant protein to produce one kilo of beef protein, about 10 for a kilo of pork protein and about five for a kilo of chicken protein.

Its environmental harm is frightening. Seventy-five percent of all agricultural land is used for animal production even though it only provides a third of global protein.

The greatest cause of biodiversity loss is loss of habitat and the major cause of habitat loss is our global food system. By cutting out meat we could return vast tracts of land (and water) to nature, to other species, rather than exterminating them in order to feed animals we fill our bellies with.

And it’s only going to get worse. Feeding the 10 billion homo sapiens we expect to be on the planet in 2050 will requite a 70 percent increase in food production.

And then there’s that little matter of global warming. Each kilo of beef produced results in 71 kilos of greenhouse gasses, pork 12 kilos and chicken 10 kilos, compared to two kilos for legumes and less than one for fruits and vegetables.

This alarming situation should be prompting intense debate. Unfortunately these days environmental issues tend to become politicized and turned into cultural brawls rather than prompting rational discussion. A couple of years ago when the inefficiency of meat-eating first become public, Texas Senator Ted Cruz’s response was “now they’re trying to take away our hamburgers.” Actually, no one wanted to deprive Ted of his hamburger, “they” were just pointing out an important fact he could use to make a better life for future Texans.

So is it hopeless? Do we just literally eat ourselves out of house and home?

The EAT-Lancet Commission on Food, Planet, Health was established to answer just such questions. The commission consists of 37 world-leading scientists from 16 countries from various scientific disciplines.

Their answer? It is possible to feed a future population of 10 billion through a sustainable food system, however it won’t be easy. It will take a substantial shift towards healthier diets, a large reduction in food waste, and major improvements in food production practices. We will, they reported, have to reduce consumption of foods such as red meat and sugar “by more than 50 per cent.”

Many people are taking notice. They may not be giving up meat, but they are eating more carefully and eating healthier meals. And there is a growing movement to reduce food waste. Furthermore, there is a lot of action on producing meat alternatives—cultured meat and plant-based “meat” that looks and tastes like the real thing. Some major food companies, including Nestlé, Tyson Foods, Cargill and JBS, have introduced plant-based products in recent years.

So there are alternatives to gaining our nutrients by cycling food though the guts of animals. And Ted can still have his hamburgers.