In response, Torben Ørvad Jensen, a reader in Denmark, asked why we don't substitute a fairly unconventional protein source -- grasshoppers -- for cattle.
"How can we get the governments around the world to see, that one of the the answer to both famine and climate change, is breeding new kinds of livestock like grasshoppers?" he asked.
"Insects are not the answer to everything," he added, "but its one of the great changes that could be fundamental to fighting climate change in the long run."
I'm not sure about the "convincing world leaders" part, but there is some research to show Jensen may have a point about insects having smaller carbon footprints than other protein sources, especially beef, which has an outsize contribution to global warming.
To try to understand why, and the limits of our knowledge about insect protein, I called up Dennis Oonincx, an entomologist at Wageningen University and Research Centre in The Netherlands. Insects are generally far more efficient at turning their food into protein than cattle, he said, which eat low-nutrient grass and burp out methane in the process.
But to date, Oonincx told me, researchers only have studied the total carbon footprint associated with one edible insect: the mealworm. According to a 2012 study Oonincx published in the journal PLOS ONE
, mealworms have a smaller carbon footprint, per kilogram of edible protein, than milk, pork, chicken or beef. Beef, for example, has a carbon footprint about six to 13 times the size of mealworms, per kilogram of edible protein, the study says.
Oonincx told me the results likely would be similar for edible crickets, but that research has not quantified exactly how much crickets contribute to climate change. Crickets likely would have a slightly larger carbon footprint, similar to that of pork or milk.
"If you look at the attributes of these crickets and these mealworms, certain things are very similar," he told me. "They both need a warm environment, so they need a lot of energy. Both are efficient at using the feed. And they have a very high edible portion.
"If you have a cow, there's a lot of the cow you're not going to be eating. And if you have a cricket, you have 80% or 90% of the animal that you can consume."
To understand how mealworms could contribute to climate change, at all you kind of need to know how they're grown -- and what the heck a mealworm farm looks like.
A mealworm farm is basically a building full of stacks of crates about 12 feet high, Oonincx said. "That's actually all you see," he said. "It's crates and crates and crates and crates."
Inside the crates are mealworms, which munch on a diet of well, meal.
What is meal? Partly wheat (also carrots, weirdly
). And more than half of the mealworm's contribution to climate change comes from growing this worm food. The other sizable chunk -- 40% to 45%, he told me -- is associated with burning fuel to keep the mealworms at a comfortable temperature of about 25 Celsius (77 Fahrenheit).
Mealworms don't like to be too hot or cold.
Burning cleaner energy -- wind or solar, for example -- would further reduce the mealworm's already-small contribution to global warming.
"It's still a very young sector," Oonincx told me. "It still needs to grow up a little bit to become more efficient, and when it becomes more efficient you'll also see the environmental impact go down. You'll be using more precise rations to feed them. You can use genetic selection to make" the mealworms better users or resources.
All of that's well and good, but how do you go about convincing everyday people -- much less world leaders -- to eat mealworms?
Aside from the gross factor, which CNN's Rachel Crane recently argued shouldn't be such a big deal ("They tasted a bit like the farm smelled -- nutty and grainy
," she wrote of crickets), part of the problem is access. In the United States, it would be more or less impossible to find locally produced mealworms for human consumption, he said.
But that's not true everywhere.
"If you're living in Holland, you would be able to order these mealworms," Oonincx told me. "You would have access to that.
"And then I would advise you to buy 'The Insect Cookbook,' or one of the insect cookbooks."
Then there's the question of variety.
Because even though the carbon footprint of mealworms is the best-researched, these nutty-flavored insects aren't necessarily the most appetizing. Oonincx told me he ate a nice mealworm bon bon, made for him by a student, just this week. But "the mealworms would not be my favorite insects to eat," he said. "I'm more a fan of cicadas and termites."