Add Atmospheric Drying To Climate Change Toll

Above photo: Tanerjo de León stands among his coffee plants in Tizamarte, Guatemala. Mariana Henninger / NBC News.

Drier air brought on by climate change could put a dent in crop yields, triggering smaller and slower-growing plants, a new study says.

“Globally, the atmosphere is drying as the climate warms up,” said Danielle Way, an associate professor of biology at Western University. “That’s been correlated with reduced crop yield.”

Because air wants to hold as much water as possible, it starts to pull moisture from plants as its dries, with potentially devastating impacts on crops and vegetation.

Way, working with researchers at the University of Minnesota, studied 50 years of data and 112 plant species, including wheat, corn and birch trees, to assess how they’re affected by drier air.

The recently published findings show plants react to atmospheric drying — even if they don’t lack water in the soil — by triggering a drought-like response, growing smaller, shorter and slower.

“Basically, they’re trying to reduce how much leaf surface there is for the water to evaporate off of,” Way said. “They’re acting like they’re drought-stressed.”

It’s that phenomenon that could result in hiked-up farming costs and decreased crop productivity, Way warns, with spinoff effects on food costs and availability.

Green spaces and trees are also at risk of the phenomenon.

“This actually might be just as significant as having dry soil,” Way said.

While the study noted impacts on crops from India to the midwestern United States, Way said Southwestern Ontario’s farm belt would also be impacted by increased dry air.

“Northern countries like Canada are particularly at risk from climate change,” she said, adding the country’s temperature could rise six degrees Celsius in the next 80 years.

Atmospheric drying has been observed worldwide for the past 20 years and is expected to rise as global warming intensifies.

Although dry soil is still a challenge for farmers, Way said irrigation can address that issue. But there’s no way to humidify the air, making atmospheric drying a big risk.

On the positive side, Way said her research could be used in the development of crops more resistant to atmospheric drying. Within the study, the team found some plants, including certain varieties of wheat, are less stressed by dry air than others.

“That variation is something we can use to breed more drought-tolerant crop species to minimize the effect” of atmospheric drying, she said.

But the long-term and essential solution is to combat climate change, Way said, adding her research highlights some of the less visible impacts of global warming.

“The way to tackle this is to tackle climate change at that large scale,” she said.