Agriculture Module Overview

Canada’s agriculture and agri-food sector accounted for roughly 12.5% of total employment in 2016¹. A changing climate has direct implications for the agricultural sector, including extreme weather events, changing crop suitability, pest distribution, and water availability^2,3, making it a priority for inclusion on ClimateData.ca. Canada’s agricultural sector is used to working with climate variability and has already implemented adaptation actions to reduce its risk to this variability. Access to climate model data can provide stakeholders in the sector with a better idea of how the climate is expected to change in their region and case studies provide examples of additional impacts and the use of climate data to better understand changing risks. The information available on ClimateData.ca is intended to inform adaptation by informing decision making, program priorities and investment decisions taken to manage additional risks of climate change.

The ClimateData.ca agriculture sector module was developed with input from a variety of stakeholders in Canada’s agricultural sector through a survey as well as engagements with experts and stakeholders. The module is currently targeted towards anyone in the agricultural sector and can inform long-term adaptation and risk management decisions.

While module content focuses primarily on Canadian impacts, the global nature of climate change means that impacts around the world will likely have indirect effects on Canadian agriculture through changes in global supply chains and trade^3,4. ClimateData.ca provides data from an ensemble of 24 global climate models which have been downscaled and bias adjusted using the ANUSPLIN-derived gridded historical dataset. Consequently, only maximum and minimum temperature and precipitation, and several climate indices based on these three variables, are currently available. Survey results indicated that wind, soil moisture and snow cover information is also required by stakeholders; unfortunately, it is not currently possible to provide these variables on ClimateData.ca. The Learning Zone section of ClimateData.ca provides further information on historical datasets, using climate data for decision making, and climate projection ranges.

Many agricultural decisions, particularly at the farm level, are made on shorter time scales than the 30-year horizons. Seasonal weather forecasts can be accessed through the Canadian Climate Data and Scenarios website. The Canadian Drought Monitor provides a variety of information on current and historical drought conditions across Canada. AgWeather Quebec  provides weather information (real-time data, forecasts, agroclimatic indices, models) that is tailored to the agricultural sector for Québec.

Moisture Extremes

Changes in the frequency and severity of extreme weather events, including windstorms, floods, and drought, are likely to be the most challenging impacts for the agricultural sector^3,5. The stakeholder survey indicated that extreme or unpredictable weather was the key current impact of climate variability on stakeholders’ work.

Heavy rainfalls can make it difficult for farmers to access fields, pose drainage challenges, and reduce yields. A warmer climate and associated increased moisture holding capacity of the atmosphere is expected to result in increased extreme precipitation⁶. ClimateData.ca provides data for several relevant indices for assessing changes in excess moisture, including maximum 1-day precipitation and wet days above several thresholds (1 mm, 10 mm, and 20 mm). Wet days above custom thresholds can also be determined using the Analyze page.

Drought is another significant hazard for agriculture which can be extremely challenging to adapt to, producing crop failures and water scarcity affecting livestock and other uses. Therefore, the agricultural module development included the addition of the Standardized Precipitation Evapotranspiration Index (SPEI) at the 3-month and 12-month time periods.

The SPEI provides an indication of the moisture balance (precipitation minus potential evapotranspiration), by combining projected changes in temperature and precipitation to give an indication of future drought risk. The agriculture sector module also includes a Drought and Agriculture case study focused on drought on the Prairies.

Length of the Growing Season

A variety of climatic and non-climatic factors determine what shape agriculture takes in a given region⁷. An important climatic consideration is the length of the available growing season. As part of module development, indices for the last spring and first fall frost dates and total length of the frost-free season were added. The last spring frost index on ClimateData.ca indicates the first date with minimum temperatures greater than 0°C (before July 15) and the first fall frost indicates the first date where minimum temperatures fall below 0°C (after July 15). The frost-free season is computed as the number of days between these two dates and provides an approximate indication of the length of the available growing season. The total length of the growing season is projected to increase, consistent with anticipated warming.

The length of the growing season is one of several other factors associated with climate change that affect average crop and forage suitability, including higher temperatures, increased CO₂ concentrations, available heat units, water availability, extreme weather events, and, in coastal regions, sea level rise^2,3. The confluence of these factors on Canadian agriculture is challenging to predict, although the Risk Management in the Grape and Wine Industry case study illustrates how multiple climatic and non-climatic considerations can be considered to manage and better understand future risk.

Extreme Heat & Heat Units

Increasing mean and extreme temperatures can have a variety of effects on grain and livestock agriculture. Extreme heat above critical thresholds can be detrimental for crop development, particularly during key flowering and seed development stages⁸. High temperatures or heat waves during summer can also have negative effects for livestock, including heat stress, reduced milk production, and reduced summer weight gain². ClimateData.ca provides projections for various indices of extreme heat, including maximum annual temperature and the number of days above a variety of maximum temperature threshold values. The projected frequency of several heat wave indices, using custom thresholds can be assessed using the Analyze page.

Warmer conditions throughout Canada also affect the available heat units for crop development. Growing Degree Days (GDD) describe the amount of heat available for crop growth by accumulating degree days when daily mean temperatures exceed a given threshold. Different crops have different heat requirements (further discussed in the Risk Management in the Grape and Wine Industry case study) and so projections of GDD using threshold temperatures of 5°C and 10°C are available on ClimateData.ca. The Analyze page permits the calculation of GDDs using different threshold temperatures.

Available heat units also affect the distribution of pests, weeds, and diseases, with warmer conditions possibly permitting increased overwintering, potential for the development of multiple generations in a year, and range expansion. This is further discussed in the Crop Pests and Climate Change case study. The threshold for survival varies by crop and pest, so to provide additional flexibility in analyzing future projections, the analysis tool on ClimateData.ca includes a custom Degree Days Above a Threshold tool on the Analyze page.