As we gallop toward 7 billion people, what can yeast teach us about population?

Love in the key of fermentation

This was written during February, the month with Valentine’s Day, which leads our thoughts to yeasts. Okay well, love. But love can lead to sex, and that leads to reproduction. Yeasts may not know about love, but they do know reproduction. So do we humans: our population here on planet earth will pass seven billion sometime this fall.

While making our bread dough rise or fermenting our potent potables, yeast eat and eat and eat, burping carbon dioxide and excreting alcohol as they go. Along with eating and excreting, they reproduce and reproduce and reproduce. While yeasts’ ability to double its population are infinite, its food supply and its environment are not. When they run out of food or poison their environment, they die as quickly as they bred.

The Reverend Thomas Malthus might have been thinking of yeast when he wrote an “Essay on Population” in 1798. The rev fretted that the human population could grow geometrically while our food supply could grow only arithmetically. We would, just as yeast do, grow too rapidly, and overtake our food supply (or poison our environment), thereby loosing the Four Horsemen of the Apocalypse with their deadly scythes of war and high food prices (The book of Revelations speaks of a “quart of wheat” costing a day’s wages). After which, as they say on the cartoon series, Futurama, “We’re boned.”

You might well argue that we have more sense than one-celled organisms (then again, if you have seen such television shows as “Jersey Shore” or “Jackass,” your skepticism is understandable).

Such well-respected academics as Jared Diamond reference Malthus, but they also toss in our society’s consumerism. Indeed, in Professor Diamond’s bestseller, “Collapse, How Societies Choose to Fail or Succeed,” he warns that the West, “consumes 32 times more resources, such as fossil fuels, and puts out 32 time more wastes, than do inhabitants of the third-world;” worrying that the “low impact” people of the developing countries are becoming “high impact” people.

View from space of “low impact” North Korea and consuming South Korea

I question the low impact of low-consuming developing countries. After all, according to defectors from North Korea, the average “low impact” peasant lives more of a hunter-gatherer existence with the countryside paying the price. In the book “Nothing to Envy,” Barbara Demick says these non-consumerist peasants made “ Barbara Demick says these non-consumerist peasants made “traps out of buckets and string to catch small animals in the field…stripped the sweet inner bark of pine trees to grind into a fine powder that could be used in place of flour.” And, because they were desperate, “They picked kernels of undigested corn out of the excrement of farm animals.”

I have no doubt that some of us consume excessively. Why would anyone need a Ferrari 458 Italia, with its 274 cubic-inch engine, 0-60 in less than four seconds, boasting a maximum speed over 200 mph, and costing about one-quarter million dollars? Answer: because it’s cool; and because at least for males, we seek prizes to indicate our status and sexual worth within the tribe. That, and the car is s-o-o-o cool. I mean look at it…I apologize, where was I?

Even if our consumption is occasionally overly indulgent, let’s be clear: The world is getting cleaner, more livable for people and animals, safer, and more sustainable than it has ever been. Consider this from Matt Ridley’s book, The Rational Optimist, “In Europe and America rivers, lakes, seas, and the air are getting better all the time…Swedish birds’ eggs have 75 per cent fewer pollutants in them than in the 1960s. American carbon monoxide emissions are down 75 per cent in twenty-five years.” In fact, “Today, a car emits less pollution travelling at full speed than a parked car did in 1970 from leaks.”

“Okay,” you might be saying, “That doesn’t matter, we are running out of room to put everyone. We need to stop having so many babies!”

We are not breeding as if we were yeast cells.

Over the past forty years, the whole world has seen dramatic drops in birth rates with a demographic transition from high infant mortality and high birth rate to lower infant mortality, and lower birth rate. The United Nations projects that the number of children per woman will drop below replacement value in 2025—and continue falling. Current momentum will take the world’s population up to around nine billion, after which it, too, is expected to drop.

So, as you sit watching your television and drinking a beer, remember what yeasts do. That, as John Ciardi said, “Fermentation and civilization are inseparable.” And be thankful you are not like yeast.

Cheers.