Is Climate Change Turning Our Vegetables Into Empty Calories?

Vegetables have been losing their nutritional luster over the last 50 years. And one scientist suggests climate change is only making things worse. udra11/Shutterstock

Life on Earth seems to follow a pretty simple routine: Where food abounds, so, too, does life.

That may be one reason algae has played such a pivotal role in natural history. These single-celled marine plants may be responsible for a dramatic ecological boom that eventually led to human life.

Few appreciate algae quite like the countless tiny marine animals, called zooplankton, that dine on it daily in oceans and lakes. In turn, zooplankton becomes food for bigger animals, which in turn nourish even bigger animals and ... well, you get the idea.

If you boost the algae population, the thinking goes, you might expect zooplankton to grow right alongside it. At least, that’s what U.S. scientist Irakli Loladze figured when he accelerated the growth of algae by shining light on it, according to Politico.

And, as his experiment showed, it worked. More tiny plants. More tiny animals. And, theoretically at least, more food for bigger animals.

algae bloom in water
Algae, single-celled plants near the water's surface, grow dramatically under bright conditions. Kichigin/Shutterstock

But Loladze's 2002 experiment hit a wall. After a brief surge, zooplankton started dying off despite being surrounded by a surplus of food.

It seemed in all of algae’s haste to grow up, it had left something important — its actual nutrients — behind. Loladze compared the new algae to junk food. And the zooplankton found themselves at the bottom of a Costco-sized bag of Cheetos.

That’s when Loladze started asking a bigger, even more troubling question. “What struck me is that its application is wider,” he explained to Politico. “It was kind of a watershed moment for me when I started thinking about human nutrition.”

If plants lose their nutritional value when they grow too fast, what does that mean for every animal, including humans, who eats them?

There’s little doubt Earth’s plant life is undergoing an unprecedented growth spurt. Even NASA has noted the planet’s increased greening over the last 35 years, as foliage snags increasing levels of carbon dioxide from the atmosphere.

map of world showing leaf and vegetation growth
An image showing the change in leaf area across the planet between 1982 and 2015. University of Boston/NASA

The greenhouse effect may paint the world as looking all bright-green and bushy-tailed. It's possibly as empty as a nothing-and-soda.

In New Scientist, writer Graham Lawton describes it as a "plague of plenty":

"According to (Loladze's) analysis, crops that grow in high CO2 are nutritionally barren, denuded of vital micronutrients such as iron, zinc, selenium and chromium. If he’s right, we’re heading for a world where there’s food, food everywhere, yet not a thing to eat."

Loladze calls it the ‘Great Nutrient Collapse’ — vegetables, like his lab-grown algae, that can't support life.

Vegetables already have been declining over the last half a century or so as nutrient-rich plants grow steadily nutrient-poor. Much of that impoverishment has been blamed on soil depletion — intensive farming techniques have laid waste to nutrients in the soil. Ultimately, that dead soil produces increasingly hollow plants and vegetables.

Plants growing in dry, depleted soil
Intense farming techniques are known to strip vitamins and minerals from the soil, and by extension, the plants that grow in it. Chailalla/Shutterstock

But, as Loladze suggests in Politico, what if the massive acceleration of plant growth on the planet is a lot like his algae experiment? Empty greens may be working their way all the way up the loftiest heights of the food chain.

From there, nutritionally crippled humans might one day hear the plaintive squeak of the zooplankton at the very lowest rung. It might sound a lot like, “I told you so.”