Climate change implications complicated

Despite all the emphasis on climate change, it isn’t at all clear what it will mean for prairie agriculture.

Yes, the frost free period appears to be increasing in many parts of the Prairies, but there’s huge variability. According to Paul Bullock, a soil scientist at the University of Manitoba, the frost free period can vary by a month from one year to the next.

Bullock gave a presentation at the recent Prairie Grain Development Committee meeting in Winnipeg. PGDC is where new lines of many types of crops are assessed for whether they will be supported for registration. Like farmers, plant breeders would love to know the implications of climate change.

I was especially interested in hearing Bullock’s presentation because we were ag college classmates. With his farm background and continuing ties to a farm in northwestern Saskatchewan, he has a practicality often lacking by those trying to make sense of climate change and agriculture.

However, Bullock isn’t a climate change denier by any means. He believes the extensive global measurements that show 2016 was the warmest year on record. In fact, most of the warmest years have been in the last decade.

He says southern Canada has seen a 1 to 2 C rise over the last 100 years. The change is most notable in higher minimum temperatures, and since 1950 the main effect has been in the winter.

However, the picture is not at all clear when it comes to characterizing the weather tendencies for growing crops in Western Canada.

Since Canadian agriculture is at the northern extreme of crop production with a short frost free period and limited heat unit accumulation, a warming climate might mean we can grow bigger crops and a wider range of crops, including soybeans and corn.

Bullock’s work and the work of other scientists show any increase in the frost free period is spatially inconsistent, meaning it’s longer at some reporting locations and shorter at others. Crop heat units have increased only sporadically, and some have actually decreased. Overall, there is actually little change over the past 10 years.

What about precipitation? Bullock says this isn’t monitored well, and it’s even tougher to draw conclusions.

In general, there has been an increase in spring rain. Snowfall is difficult to measure accurately, but it has gone down.

Following the widespread prairie drought in 2002, many big projects geared up to study how to cope with a lack of rain. By the time those projects were up and running in 2005, the wet years had started. In 2011 there were a record number of unseeded acres in Manitoba because of flooding, which were followed by a lack of rain that hurt the crops that had been seeded.

Will increased levels of carbon dioxide in the atmosphere actually aid plant growth? More uncertainty. And then there are the indirect effects of changing weed, disease and insect pressure. It’s reasonable to expect a broader range of pests.

An increase in severe weather seems likely. More global heat should mean more low-level moisture and the greater potential for storm energy.

In the end, even someone with Bullock’s credentials can’t provide much practical guidance for farmers and plant breeders. The potential exists for increased floods as well as droughts in addition to more severe weather.

“Can we push coping mechanisms wider?” asks Bullock.

Increasing crop production resilience to weather extremes may sound like a strategy, but it won’t be easy to accomplish.

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