Understanding and Assessing Impacts
To better understand how Calgary’s climate may change in the future, The City partnered with the Calgary Airport Authority, Pacific Climate Impacts Consortium (PCIC) climate experts, and GHD (an engineering consultancy with climate experts) to develop climate projections that could be used for risk assessments as well as adaptation planning and other engineering projects. Details on the climate projections are summarized in the Climate Projections for Calgary Report, available online.
Historical weather data was sourced from the Environment and Climate Change Canada (ECCC) station at the Calgary International Airport (which began monitoring in 1953), with quality assurance/quality control conducted by The City of Calgary from 1960-2014. Observed precipitation, air temperature, wind speed and direction, relative humidity, and solar radiation data was collected from the airport. The historical data was then perturbed to the climates of the 2050s and 2080s. The climate projections utilized the Canadian climate normals period (1981- 2010) as the Global Climate Model (GCM) baseline period. The 2050s climate was based on the GCM projections for 2041 to 2070 (mid-century), and the 2080s climate was based on the GCM projections for 2071 to 2100 (end of century). Additionally, the climate projections utilize the ensemble of the CMIP5 global climate models for the RCP8.5 emissions scenario.
PCIC downscaled the daily air temperature and precipitation data using a statistical downscaling methodology (e.g., the Bias Corrected Constructed Analog with Quantile mapping, version 2 [BCCAQv2]) to a grid of approximately 6 by 10 km. The PCIC data include 27 GCMs, and three GCMs have two runs each, for a total of 30 data sets at this grid size. The grid size was selected based on the availability of gridded historical climate observations. The wind, solar radiation, and relative humidity data were dynamically downscaled with Regional Climate Models (RCMs) to a grid approximately 15 by 25 km through the North America Coordinate Regional Downscaling Experiment (NA-CORDEX). The grid size was selected based on the availability and resolution of RCMs. Data for up to 16 GCM pairs is available through this data source. The available high-resolution datasets are currently the highest-resolution data available and provide a clear climate change signal for Calgary within the level of certainty available in current climate modelling. Climate models use approximations to describe the complexity of the climate system while not being able to precisely define phenomena at a scale smaller than their grid cell.
For The Project, The City of Calgary utilized The City’s climate projections to determine climate likelihood scores, in combination with assessing historical weather impacts to determine consequence scores to assess climate risk to the project. The climate hazards of interest that could affect The Project include: extreme heat, increasing air temperatures, wildfires, drought, short duration high-intensity rainfall, severe storms, high winds, heavy snowfall and river flooding.
These changes could impact the infrastructure (built and natural), users of Marda Loop and operations and maintenance of The Project.