Understanding and Assessing Impacts
Flooding is common in Ontario, and while it is a natural process, it can become hazardous when people, property or natural systems are exposed. While Durham Region has been fortunate to avoid major catastrophic events, it has experienced numerous localized flooding incidents, with the record breaking 2017 and 2019 Lake Ontario Floods being recent examples. High water levels, particularly along the lakeshore, coupled with both incremental and gradual changes in precipitation patterns and storm events drove the need for action. Between 2012 and 2014, the Region of Durham undertook a climate modeling exercise with SENES Consultants Ltd. to predict future climate in the Region for the 2040-2049 period. This study was one of the first steps towards the development of the Durham Region Community Climate Adaptation Plan which was published and endorsed by regional council in 2016, and subsequently received a Sustainable Communities Award from the Federation of Canadian Municipalities. In 2020, the Ontario Climate Consortium (OCC) determined the North American Coordinated Regional Climate Downscaling Experiment (NA-CORDEX) as the best-suited climate model ensemble to conduct the climate modeling for Durham Region. The data from this model captures the influence of the Great Lakes, which was important since Lake Ontario has a great influence on Durham Region’s weather and climate patterns. Using this data source, bias corrected climate projections were produced for 52 climate parameters for RCP 8.5 (high emissions) and RCP 4.5 (medium emissions) scenarios for the short (2011-2040), mid (2041-2070), and long (2071-2100) term. This analysis demonstrates that Durham Region will likely experience a warmer and wetter climate, with a longer growing season. The Region is also expected to experience more variable weather patterns and experience higher intensity storms with greater amounts of precipitation in all seasons. This may impose threats to the health of communities, its natural systems, infrastructure, agriculture, economy, and services within the Region.