Agriculture must adjust to variable temperatures

DAUPHIN, Man. — A University of Winnipeg scientist has been predicting for the last several years that the climate of southern Manitoba may soon resemble Nebraska.

This would mean that in a matter of decades, Manitobans will apply more sunscreen to cope with 30 degree days in the summer.

While it’s true that climate change will make the southern Prairies warmer, western Canadian farmers should be particularly concerned about weather variability, said David Barber, an Arctic and climate change expert at the University of Manitoba.

“(Based on) the trends, you can say on average we’re going to look more like Nebraska,” Barber told the Hudson Bay Route Association annual meeting in Dauphin April 3. “Unfortunately, the variability is going to be higher. That’s variability in temperature and precipitation…. If you’re a farmer, you have to start thinking about how you do agriculture in those kinds of conditions.”

He said there is evidence that the climate is already more variable.

Data suggests that the Rossby Wave, an atmospheric pattern related to polar air moving south and warm equatorial air moving north, is oscillating at a slower rate.

“If you look at a weather forecast (on TV), you will see a wave … going around the planet,” Barber said.

“Scientifically it’s called the Rossby Wave. Typically people talk about it as what’s going on with the jet stream. The jet stream is set up between this gradient (in temperature) between the Arctic and the southerly latitudes of the planet.”

Barber said the temperature gradient from north to south is changing and slowing the speed of the Rossby Wave.

As a result, periods of cold weather and warm spells are lasting longer. Or, in scientific terms, weather is becoming more persistent.

“If you have a weather system that is drier, that weather system (now) stays over you for a longer period of time,” Barber said.

“This persistence pattern is related to the fact that we are losing ice cover in the Northern Hemisphere.”



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