Plants could lose ability to absorb lots of CO2, threatening entire food chain

24 Oct 2018

Image: © THPStock/

Plants absorb enormous quantities of CO2 globally, but new research suggests this ability could drop dramatically in the years to come.

The plants that make up the vast ecosystems of our planet play a crucial role in limiting the amount of CO2 in our atmosphere, including what is released en masse by ourselves annually. Certainly, without it, our planet would be almost uninhabitable.

However, new research conducted by a team from Indiana University in the US discovered something rather worrying when analysing the amount of nitrogen in some parts of the world. The findings, published in Nature Ecology and Evolution, showed that in grasslands and forests – which are not directly fertilised – the availability of nitrogen to plants is falling.

The element is an essential nutrient for plant development and is a key ingredient in human-made fertilisers, so much so that there are now fears we may have caused serious damage to the environment.

Total opposite is true

This, according to researcher Lixin Wang, has led to a belief that we have an overabundance of nitrogen when, in fact, the total opposite is the case in natural systems. “In such systems, which cover a large part of the world, demand for nitrogen is rising at a faster rate than the supply of nitrogen,” Wang said.

The crux of the matter is that when a plant experiences nitrogen deficiency, it is not able to absorb the levels of CO2 that it would when healthy.

“We know that plants reliably suck up CO2 that we emit into the environment,” Wang said. “But the problem right now is if plants are suffering more and more nitrogen limitations, it means they will be able to take up less and less of the extra CO2.”

Meanwhile, the paper’s lead author, Joseph Craine, emphasised the potential damage to our planet this would cause. “Not only will plants be more stressed for nitrogen,” he said, “but so will animals that eat plants. Less nitrogen in plants means less protein for herbivores, which could threaten the entire food chain.”

Colm Gorey was a senior journalist with Silicon Republic