7 December 2023

Canada’s grasslands are getting hotter and drier


A study by the University of Alberta has described for the first time the changes that have occurred in the country’s grasslands over the past 120 years and the consequences for agriculture

by Matteo Cavallito


Over the past 120 years, Canada’s grasslands have become warmer and drier, a study has found. The investigation, based on an analysis of scientific literature, examined the effects of climate change in the so-called Prairie provinces, i.e., the cultivated lands of Alberta, Saskatchewan and Manitoba, Canada’s main agricultural area, from 1901 to 2021.

This survey, conducted by the University of Alberta and published in the Canadian Journal of Plant Science, showed a steady trend of increasing temperatures and disturbances with frequent and heavy rainfall. The analysis, recalled Emmanuel Mapfumo, a professor in the Canadian university’s Faculty of Agricultural Sciences and co-author of the research in a statement, is among the first to explore the impact of climate change on farmland in that area.

Grasslands have become warmer

The analysis, the statement says, revealed a trend toward drier conditions. “Off-season precipitation and snow cover duration in Canada have decreased since 1950,” the study states. In addition, “The number of frost-free days has increased across Canada, on the Prairies and southern Saskatchewan since 1900.”

Examining historical changes based on articles published in scientific studies and websites, books, and government documents, the authors found increases of up to 6 °C in average, minimum, and maximum daily air temperatures. “Particularly concerning was a consistent finding across the data that minimum air temperature, or the lowest temperature recorded during the day, increased anywhere from 1 C to 4.5 C,” the statement adds.

The effects on crops

“Overall, studies focusing on the Prairie Provinces in Canada have shown accelerated changes in several climate parameters over time, affecting cropping areas and crop yields.” The consequences, however, are manifold and produce advantages as well as disadvantages. Warmer temperatures, for example, allow for the northward expansion of some crops such as corn.

At the same time, however, they can create drier conditions elsewhere by increasing the likelihood of plant disease outbreaks with earlier emergence of pests, the note notes.

Moreover, according to some studies, “Elevated CO2 concentrations increase photosynthesis, biomass production, and yield of C3 plants (which are typical of temperate climates, ed.) , yet smaller or negligible increases have been found for C4 plants (typical of warm climates, ed.) such as corn,” the researchers explain. At the same time, “a meta-analysis concluded that crops such as wheat, barley, and rice had 10%–15% decrease in protein content when grown under elevated CO2 concentrations compared to ambient conditions.”

Mitigation solutions

Grasslands, which are estimated to store one-third of the earth’s global carbon stock, have long been targeted in the studies on the impact of climate change on soils and crops. A phenomenon that occurs in many ways by affecting agriculture. In Canada, the authors recall, the agricultural sector is worth more than $30 billion, or about 1.5 percent of GDP, and employs nearly 120,000 workers.

In this context, Mapfumo notes, “It’s vital to find ways to mitigate local climate change.” A phenomenon “twhich affects the ability to grow various crops and hence affects crop yields, and has ripple effects such as higher food costs.”