Prairies definitely getting warmer: researcher

When grandparents reminisce about walking uphill to school, through deep snow in bitterly cold winters, their memories may not be blurred by time.

Winters were colder in the past, says climate researcher David Sauchyn of the University of Regina.

January 2019 marked the 409th consecutive month where world temperatures were above the 20th century average.

“There was a shift in the mid-20th century from cooler years to warm years and every year has more or less been getting warmer since the 1980s,” he said at the Alberta Soil Science Workshop held in Calgary Feb. 19-21.

“This is a very strong signal the climate is changing. There are also some limitations in this information,” he said.

Written records are short term, but it is known there was a shift in the climate around the mid-19th century, with a rapid turnaround about 150 years ago. The globe had been cooling slowly for the previous 2,000 years.

His research focus involves nearly 40 years of long-term studies of centuries-old trees in southwestern Alberta. Tree-ring growth provides a record of climate that occurred on the Canadian prairies for centuries before European settlement.

They have traced conditions between the years 1108 to 2010 and have learned there were serious prairie droughts that lasted a century.

“They will happen again. Geologically speaking they just happened a few centuries ago,” he said.

Another indicator of change is ocean temperature. Western Canadian weather is affected by the Pacific Ocean and its changing temperature determines how much water could arrive as rain or snow.

“Our summer temperatures are not heating up. It is getting less cold. The biggest impact of global warming is not on temperature. It is on the water,” he said.

Research also shows tremendous variability in the weather from one year to the next, but prairie winters are not as cold as they used to be.

The climate of southwestern Alberta is typically warmer than the rest of the Prairies, but there has been a 5 C increase in winter temperatures for Edmonton, Regina and Saskatoon.

“The strongest signal of a warming climate on the Canadian Prairies is in the lowest winter temperatures,” he said.

In the 1950s to 1970s, the Prairies suffered extreme cold in which temperatures were below -35 C for extended periods.

“We are not getting really cold winters, which is hard to say because we have just had a cold snap. We just had a normal winter,” he said.

Various climate models used around the world show discrepancies when predicting high and low temperatures, but all agree the world is getting warmer, he said.

Winter will be warmer and wetter with zero to 25 percent more precipitation on the Prairies.

“Most of our water comes from melting snow. The models say going forward we can expect more precipitation in the winter and spring,” he said.

Summer could also be warmer but there is a disagreement on the level of precipitation. There could be more rain but warmer temperatures encourage more evaporation.

Producers must find ways to work with the effects of drier summers.

A warmer climate could cause a whiplash effect where yields are high one summer and low the following year because of severe drought.

“The most important climate change we are experiencing is the increase in the volatility of our weather. It is becoming more extreme and more variable,” he said.

There are three sources of uncertainty when predicting the future climate. Greenhouse gas emission levels, climate models and natural variability are complex factors.

“Our ability to predict the future is not constrained by what we know about people but it is constrained by what we know about nature,” he said

As variability continues, new ways to capture winter water are needed. Sauchyn suggested the soil could be used to store more water in spring and winter rather than building more dams.

Native mixed grasslands on the brown chernozem soil of southwestern Saskatchewan and southeastern Alberta have withstood extremes over the centuries and remained a healthy ecosystem.

“All the people who say we should be mimicking this ecosystem, it intuitively makes sense,” he said.

Healthy soil that stores water and increases infiltration capacity, as well as more plants capturing snow on a diverse landscape, is one way to go.

“It makes sense to maintain the resilience and health of the soil landscape,” he said.

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