Farmers must brace for severe heat, drought

Understanding climate change vital for agriculture, writes Elaine Wheaton

Much of southern Canada has been experiencing persistent hot and dry weather.

The Canadian Drought Monitor, Canada’s official source for drought information, shows dry to drought conditions across much of Canada as of July 31. Large areas are hot spots of drought in the Prairie Provinces, including southeastern Alberta, southwestern and central Saskatchewan and the inter-lake and eastern areas of Manitoba.

The Drought Monitor states that agricultural impacts have been moderate to severe in many regions.

Strong signals of a changing climate are already clear and having effects, especially those changes affecting agriculture. This knowledge is vital as agriculture is such a critical sector.

Examples of changes in agricultural central Saskatchewan since the 1960s include: the frost-free season has increased about 30 days, heat units have increased, snow cover at the end of March has dwindled from many centimetres to near zero, and the risk of really cold days is fading (data from Wittrock 2018).

Also, plant hardiness zones have experienced considerable northward shifts in the Prairies (Mckenney et al. 2014). Considerable evidence shows that such trends will continue.

These changes have many repercussions for agriculture, Some are positive, especially with awareness and adaptation. However, many are negative. Also, adaptation can be costly and disruptive.

How is the current heat and drought related to climate change and global warming? Much evidence shows that climate change is increasing the risk of droughts and hot weather on the Prairies and elsewhere globally.

Global warming is the temperature aspect of climate change, which is also causing the retreat of glaciers, sea ice losses, increased atmospheric water vapour and changing weather patterns.

What is the difference between weather and climate?

Climate consists of the patterns of weather, including averages, ranges and trends. A specific hot or cold spell, for example, is weather and not climate or climate change. In other words, weather is what you get, and climate is what you expect.

Climate scientists examine the patterns of weather using statistics, such as averages, variations, and trends. For example, the number of cold spells in winter and snow cover area are showing large declines since the 1960s. This confusion of weather and climate has been used in misinterpretations to dismiss concerns of climate change.

What are the causes of climate change now? Climate scientists have found that the human influence has been the dominant cause of the observed warming and other changes since about 1950. A main cause is the increase of greenhouse gases caused by the burning of fossil fuels. Therefore, the reduction of greenhouse gases is necessary to reduce the magnitude and rate of climate change. In turn, this would make adaptation less costly and disruptive (Warren and Lemmen 2014).

What can we expect for future heat and droughts? Future projections of climate change show increasing severity of heat and droughts. Past droughts may seem mild compared with future droughts. Paleo-assessments of droughts for the past 600 years also show the potential for worse droughts than those since 1900.

It may seem strange, but the future projections also indicate increasing excessive precipitation. This is because the hydrological cycle is enhanced by increasing temperatures and is able to achieve both greater drying and precipitation.

Agriculture has a high capability to adapt; however, taking advantage of these changes requires careful planning for even more enhanced adaptation.

An important step is to be aware of changes, and to assess these past changes and future expected changes. Best management practices, for example, already have shown progress in adapting to changing climate conditions.

Elaine Wheaton is a University of Saskatchewan professor in geography and planning and the School of Environment and Sustainability. This article was prepared for the Saskatchewan Institute of Agrologists.