Climate Change and Plant Nutrient Levels

article image
Photo by Getty Images/sanjeri
Even leafy greens are storing more carbohydrates than they used to.

Nutrient deficiencies might not be the result of poor diet. A landmark study from 2004 revealed that many fruits and vegetables contain less protein, iron, calcium, and vitamin C than they did in the 1950s, though carbohydrate levels have increased over the same time span. While some researchers think this discrepancy is explained by farmers growing sweeter cultivars, others believe a bigger factor is at play — Earth’s changing atmosphere.

Earth’s atmospheric carbon dioxide levels are rising. Within the next 50 years, carbon dioxide concentrations are expected to reach 550 parts per million, which is approximately double the amount measured before the mid-19th century. Farming will be profoundly affected: Research shows that elevated carbon dioxide levels will affect 95 percent of plant species — including staple crops, such as wheat, rice, and potatoes — by causing essential mineral levels to drop by 6 to 8 percent. Though this decrease may sound negligible, it will have far-reaching consequences for global health.

The impacts of an increasingly carbon-concentrated atmosphere were first observed in zooplankton, microscopic sea creatures that primarily feed on algae. Scientists found that shining lights on water caused more algae to grow in it, which should have benefited the hungry plankton. Instead, the zooplankton struggled to survive, and analysis revealed that the algae grew faster, but at a lower nutritional quality. The low-nutrition algae compromised the zooplankton’s ability to thrive.

Scientifically, this makes sense. More food doesn’t always lead to better health, and the two are often inversely linked. Plants rely on both light and carbon dioxide to grow, so rising carbon dioxide levels could have a similar effect on land plants’ nutritional value. When they can more easily convert sunlight into food, plants pack in a higher concentration of carbohydrates at the expense of protein, zinc, iron, and other essential nutrients.

Will the increase of carbohydrates and consequent decrease of other nutrients in your meals make a difference for your health? According to initial evidence, yes. Nutrient-rich plants are critical for combating health problems around the world, and lower levels in natural sources put vulnerable populations at risk. For instance, estimates show that 150 million people may be at risk for protein deficiency by 2050, and iron deficiency may affect a billion pregnant women within the same time frame. Most disturbingly, the impact of this nutrient collapse is already apparent. Research shows that protein levels in goldenrod pollen are down a third from 1850s levels, to the detriment of honeybee populations around the world.

Increasing carbon dioxide levels will cause ripple effects throughout the entire ecosystem in ways scientists can’t anticipate.