Climate change impacts on agriculture

Agricultural production is highly dependent on weather and climate. Without adequate rainfall and appropriate temperatures, crops fail and pastures become barren. Interestingly, the opposite is also true: weather and climate are influenced by agricultural practices. By managing croplands and pastures, farmers influence a series of physical, chemical and biological interactions between the Earth's surface and the atmosphere that can affect air temperature and precipitation in many ways.

Climate change projections do not rely on one model, but on many models with different assumptions. For this reason, the potential impacts of climate change are projected using a wide range of models to account for different future possibilities. When multiple climate models show similar outcomes, there is more confidence in the future climate impact projections.

Global climate models

Scientific projections about the future of our climate are developed by running global climate models that are based on scenarios that represent a range of possible future conditions. This includes greenhouse gas (GHG) concentrations in the atmosphere, population size, socio-economic development and technological changes. In addition, many models using different assumptions are used so that uncertainty in the outcomes are better understood. Climate models analyze long timespans and predict how average conditions will change in a region over the coming decades. Climate models include more atmospheric, oceanic and land processes than weather models do, such as ocean circulation and melting glaciers.

Global climate models show growing agreement within the scientific community that our future climate will be warmer with more extreme climate and weather events.  The magnitude of the warming will vary based on many assumptions, including the measures that are taken to reduce greenhouse gas concentrations in the atmosphere. Climate records clearly show that Earth has been heating up for more than a century, and especially over the last 50 years. In fact, 17 of the 18 warmest years on record have occurred since 2001.

Source: NASA Goddard Institute for Space Studies Surface Temperature Analysis (2021).

Description

This graph shows the global annual temperature trend relative to the 1951 to 1980 average from 1880 to 2020. The temperatures are lower than the average for this period until the 1940s, and a steady upward trend is seen starting in the 1980s. The 2020 temperature was one degree warmer than the 1951 to 1980 average.

Current impacts from climate change in Canada

There is considerable evidence and data to suggest that the climate in Canada is already changing. Countries in northern latitudes are expected to feel greater changes than those further south, and Canada is no exception.

• Annual and seasonal mean temperatures across Canada have increased, with the greatest warming occurring in winter. Between 1948 and 2016, the best estimate of mean annual temperature increase is 1.7°C for Canada as a whole and 2.3°C for northern Canada.
• Climate change has increased the likelihood of some types of extreme events across Canada; including wildfires, flooding, hail storms, and tornadoes.
• Canada's Arctic and alpine glaciers have thinned over the past five decades due to increasing surface temperatures; recent mass loss rates are unprecedented over several thousands of years.
• The seasonal timing of peak streamflow has shifted, driven by warming temperatures. Over the last several decades in Canada, spring peak streamflow following snowmelt has occurred earlier, with higher winter and early spring flows.
• Periodic droughts have occurred across much of Canada, but no long-term changes are evident. Future droughts and soil moisture deficits are projected to be more frequent and intense across the southern Canadian Prairies and interior British Columbia during summer, and to be more prominent at the end of the century.

For more information:

• Canada's Changing Climate Report
• Climate Change Publications

To learn more about how Canadians are trying to adjust to present-day effects of global warming visit The Climate Atlas of Canada. The atlas combines climate science, interactive mapping and storytelling to bring the global issue of climate change closer to home for Canadians. It is designed to inspire local, regional, and national action that will let us move from risk to resilience.

If you'd like to explore case-studies and download location based climate data by sector, visit ClimateData. This is a data portal produced collaboratively by the country's leading climate organizations and supported, in part, by the Government of Canada. The goal of this portal is to support decision makers across a broad spectrum of sectors and locations by providing the most up to date climate data in easy to use formats and visualizations.

Impacts to Canadian agriculture from climate changes

How will climate change impact Canada and Canadian agriculture? Increased temperatures, longer growing seasons, shifting precipitation patterns and an increase in frequency and intensity of extreme events from climate change will bring both challenges and opportunities to Canada's agricultural sector.

The impacts of climate change will not be uniform across Canada, nor will they be uniform across seasons.  In terms of production, there are likely to be opportunities, in some regions, to grow warmer-weather crops and take advantage of a longer growing season with less cold weather events that can damage crops. There will also be challenges to production arising from water stress (flooding or drought), heat stress, wind damage, increased pest and disease pressures, and the impact from these multiple stressors on soil health, which can reduce the productivity, profitability and competitiveness of Canadian farmers. 

Opportunities

A warming climate may provide opportunities for agriculture in certain regions with an expansion of the growing season in response to milder and shorter winters. This could increase productivity and allow the use of new and potentially more profitable crops. For a high-latitude country like Canada, future warming is expected to be more pronounced than the global average. Northern regions and the southern and central Prairies will see more warming than other regions. Most regions will likely be warmer with longer frost-free seasons. Atmospheric carbon dioxide (CO²) concentrations are expected to increase in the future which promotes the growth of small grains and oilseeds by increasing photosynthesis and crop water use efficiency. Corn will mostly benefit from increased water use efficiency and less from increases in photosynthesis. 

Challenges

Increased temperatures, longer growing seasons, shifting precipitation patterns and an increase in the frequency and intensity of extreme events from climate change will bring challenges to Canada's agricultural sector. In most of Canada, springs will be wetter, summers will be hotter and drier, and winters will be wetter and milder. Changes in temperature and precipitation patterns will increase reliance on irrigation and water-resource management, notably across the Prairies and the interior of British Columbia where moisture deficits are greatest, but also in regions where there has not traditionally been a need to irrigate. In many parts of the country, wetter than normal springs will present challenges such as the need to delay seeding. Flooding and other extreme events, including wildfires, may result in loss or relocation of livestock and damage to crops; and increased frequency and intensity of storms could result in power outages, affecting livestock heating and cooling systems as well as automated feeding and milking systems. 

A rise in the incidence of days over 30 °C will bring challenges to both crop and livestock producers. Some crops, such as canola and wheat, are particularly vulnerable to heat stress during the flowering period, and high temperatures can result in lower weight gains in livestock, reduced reproductive capacity, reduced milk and egg production, and in extreme cases,  livestock mortality. Longer, warmer summers and milder winters will result in greater overwinter survival of pests and diseases, as well as a northward expansion of pests and diseases not currently found in Canada. Additional pest pressures can impact both crop and livestock production and could potentially affect the marketability/acceptability of Canadian exports. Plant protein may decrease in the future under higher atmosphere CO² resulting in lower grain quality.

While growing seasons will be longer, variability in growing seasons will bring challenges.  The last spring frost and first fall frost dates have remained highly variable across the country, making it difficult for farmers to manage seeding and harvesting accordingly, although this may be less of a challenge as warming continues. Tree fruit crops are particularly vulnerable to late frosts occurring during flowering, which may affect yields. Climate change may also affect the prevalence of pollinators as plant flowering periods may change and the range of pollinators may be altered.

Impact by region

While all of Canada will be affected, the impacts will not be uniform across the different agricultural landscapes, with distinct issues for five regions: 1) Pacific Region [British Columbia]; 2) Prairies Region [Alberta, Saskatchewan, Manitoba]; 3) Central Canada [Ontario, Quebec]; 4) Atlantic Canada [New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland, Labrador] and 5) Northern Canada [Northwest Territories, Nunavut, Yukon].  Below are the top impacts per region:

1. Pacific Region
   • Access to adequate water is the greatest concern for producers in a number of regions in British Columbia. British Columbia relies on the annual snowpack and glacial meltwater for stream water recharge. As glaciers recede and less precipitation falls as snow, water levels will be reduced, which may lead to reduced soil moisture and water scarcity through the growing season.
   • Temperature increases will would add more frost-free and growing degree days that could improve yields, and enable new cropping options in some regions.
   • More frequent and intense storms, floods, and drought are expected annually, adding uncertainty to food production.
   • Warmer winter temperatures could increase pest and disease pressure by improving over-wintering survival of new and existing species.
   • Tree fruit crops may be especially vulnerable to variable autumn and spring frosts.
   • Sea level rise and salt intrusion may impact coastal agriculture.

2. Prairie Region
   • Increased frost-free periods may provide opportunities for the expansion of warm weather crops such as corn and soybeans as well as a potential northwards expansion of agricultural production where soils permit.
   • Reduced precipitation later in the growing season, coupled with increased heat will cause stress to plants and may have a negative impact on yields.
   • More frequent spring flooding, summer droughts and extreme weather events are expected.
   • Reduced streamflow, less snowmelt to recharge rivers and earlier peak flows could lead to reduced access to water for irrigation during the summer and greater competition for groundwater reserves.
   • A warmer climate may bring new pests and diseases.
   • Increased temperatures could affect livestock health, resulting in reduced milk, egg and meat production and even fatalities; increased cooling costs for producers.
   • Higher CO² levels may result in greater productivity from crops such as  wheat, barley, canola, soybeans, and potatoes.

3. Central Canada
   • Warmer spring weather will extend the growing season, however wetter springs may delay planting/seeding operations due to waterlogged fields and increase soil erosion and nutrient runoff.
   • Increased evapotranspiration due to higher summer temperatures could increase water stress in plants but may be offset by increases in water use efficiency as a result of higher atmospheric CO².
   • For northern areas of central Canada, there is an increase in frost-free days, a longer growing season, opportunity for warmer-weather crops (including corn, soybeans), as well as a potential northwards expansion in agricultural production where soils permit.
   • More variability in spring and fall temperatures can stress fruit trees causing blossom loss due to late frosts.
   • Increased temperatures could affect livestock health, resulting in reduced milk, egg and meat production and even fatalities; increased cooling costs for producers.

4. Atlantic Canada
   • Extended periods of hot temperatures resulting in reduced soil moisture and extended drought periods are a concern (increased pressures on yields and forage shortfalls,  etc.)
   • Extended periods of drought and dry conditions could put pressure on water table elevations and the need for irrigation.
   • Increase in frost-free days, longer growing season, opportunity for warmer-weather crops (including corn, soybeans).
   • Rising sea level, erosion and storm surges could negatively impact the Atlantic region, particularly Prince Edward Island and eastern New Brunswick.
   • Flooding or waterlogged soil due to increased precipitation could negatively impact agriculture. Wetter springs may delay planting/seeding operations due to waterlogged fields.
   • In some parts of Atlantic Canada, the milder winter temperatures could have implications for over-wintering of pests and diseases.
   • Intrusion of salt water in agricultural lands is a concern and could compromise soil and surface water quality.

5. Northern Canada
   • Impacts on viability of ice roads, affecting access and food security for imported foods as well as for locally harvested food.
   • Increased frost-free season could facilitate a limited expansion of northern agriculture assuming appropriate soils and adapted cultivars.
   • Longer growing seasons may increase the potential for greenhouse production due to reduced winter heating costs.