CALGARY – Plants stressed by drought and rising temperatures brought on by global warming may actually release more greenhouse gases into the environment, says research from the University of Calgary.
Scientists looked at the methane levels emitted by six crops grown in Canada: faba beans, sunflowers, peas, canola, barley and wheat.
They measured the amount of methane emitted by the plants normally, and under conditions simulated to mimic global warming, including higher temperatures, drought and increased ultraviolet-B radiation.
Methane is a greenhouse gas that traps heat at a much higher rate than carbon dioxide.
“I’ve been of the opinion for some time that methane is somewhat ignored, and I think it’s just as important as carbon dioxide in the whole global warming debate,” said author David Reid, an associate professor at the university.
“So if plants produce a little bit, we were curious to know what would plants in the near future, maybe slightly warmer, slightly drier, maybe a little more UV light, how would they respond? Would it affect them or not?”
Under normal conditions, the crops emitted different amounts of methane, he said, although the levels were quite small for all.
The amount of methane went up different degrees under global warming conditions.
He pointed out that plants on balance are “our saviours” when it comes to absorbing carbon dioxide from the air, and have an overall positive effect on climate change.
Still, an increase in methane is not a positive step, Reid said.
“If the world gets a lot more environmentally stressful, this phenomenon will increase, and it will complicate the story a lot, which we don’t need.”
Simon Donner, a University of British Columbia professor, said research into methane has become important for people trying to understand climate change.
“Carbon dioxide gets all the press, but methane’s extremely important,” said Donner, who was not commenting on Reid’s research specifically.
“Some of the biology and the chemistry of how it gets emitted, we’re still learning about, it’s still quite complicated.”
He said more studies are needed to really understand how plants or the soil around them contribute to methane in the atmosphere.
“We need these sort of detailed studies to really understand it well.”
A study published in 2006 stirred controversy when researchers in Germany suggested for the first time that plants emit up to one-third of the methane in the atmosphere.
Its authors quickly clarified that while plants may release methane, they cannot be blamed for modern climate change since they existed long before human influences.
Reid said research is already demonstrating that climate change is extremely complex and could have negative effects in ways we haven’t anticipated.
“It’s another warning that we’re messing things up at a hell of a rate.”