Christopher Bonasia
The Advocate
Canadian agriculture has likely benefitted from a “warming hole” that has moderated how the country experiences the climate change impacts felt by the rest of the world, but scientists are unclear on how long that will last.
A warming hole is what scientists call an area where temperatures do not warm as rapidly as expected, even amid broader global warming trends.
The warming hole phenomenon has been well documented in published research. Scientists first began documenting climate change in the 1950s, but as data showed temperatures around the world rising on average, they noticed a different trend across the North American Southeast and Midwest — those parts of the continent showed unexplained cooling.
In the U.S. Corn Belt, maize yields increased by 5 to 10 per cent each year in the mid-20th century, linked to cooling temperatures. There has also been notable cooling in the wheat growing areas of Canada.
Study looked at effect on farming
The warming hole’s influence on North American food production was raised again recently in a new study from Stanford University, entitled “A half-century of climate change in major agricultural regions: Trends, impacts, and surprises.”
Among the authors’ observations, global yields for major crops like wheat, maize and barley were 10, 4 and 13 per cent, respectively, lower than they would have been without climate change. Although past research has indicated some climate impacts — like warmer temperatures and longer growing seasons — might increase crop production, “losses likely exceeded those benefits,” the authors write.
Interestingly, for soybeans and rice, “carbon-dioxide benefits likely exceeded climate-related losses.”
Crop data studied
The main point of the research was to analyze historical data of crop yields across the world and compare it with projections from climate models. The study showed that the models, for the most part, aligned with the impacts that were actually observed, though they consistently overestimated warming and drying in North America, so crops in large areas of Canada were not affected as severely. Researchers chalked this up to the warming holes’ influence.
The trend is both easy and difficult to square away with public discussions about climate change. On the one hand, the seriousness of climate change continuously fails to gain traction among many in the North American agriculture sector, which could be connected to climate impacts being more moderate than elsewhere.
Other devastating effects
But both Canada and the U.S. have experienced devastating consequences of climate change, like worsening storms, heat waves and more intense wildfire seasons. And while warming may be more severe in the rest of the world, average temperatures across the country are noticeably rising in North America, too. The prairie provinces in particular have experienced significant drought conditions in past years, though some farmers have noted past droughts — like that of 1945 that was declared an emergency crop year under the Prairie Farm Assistance Act — to suggest that those occurrences are not proof of climate change.
However, scientists have not been able to clarify the cause of the trend, and so they also are not able to project when it may or may not cease to lessen climate change’s impacts on North American crops.
The researchers of this study suggest that the warming hole could be a result of the climate changes felt across the world and so might persist into the future. However, they note that analyses of other variables indicate potential future drying that could worsen the outlook for Canadia crop growing.