The negative effects of a changing climate are already being felt on our built environment and, over the coming decades, the effects are expected to become worse. This article will help you understand what changes are occurring and how they will impact your buildings and property. Armed with this knowledge we can start contemplating mitigation strategies to make our buildings more resilient and to lower the risk of catastrophic damage.
The Reality of Climate Change
Climate change is coming and we are beginning to see the impacts of one of the greatest threats to our future. The 10 warmest years on record have all occurred since 1998i. Climate experts predict that 2010 to 2020 will prove to be the hottest decade ever recorded. With these climate changes, major Canadian cities are experiencing gradual changes in day-to-day weather as well as extreme weather events with increasing frequency. In Toronto, the July 8th, 2013 rainstorm brought more rain in two hours than Toronto usually receives during the entire month of July. Economic losses were estimated at close to $1 billion in damages, the most expensive natural disaster ever in Ontario.ii Regardless of what we do now as a world community to reduce the sources of climate change, we are already committed to at least 50 more years of impacts. The two biggest changes that climate change will have are described below.
What to Expect?
The average temperature in Canada increased by 1.5°C over the last 65 years. Even more shocking is that this increase was twice the global average. Modest climate models under a low greenhouse gas emissions scenario (GHG) predicts that major Canadian cities will see temperatures increase by at least another 1.5-2.5°C in the summer and 3-7°C in the winter by 2050.
Canada as a whole has become wetter with an increase in average annual precipitation of approximately 16% in the last 65 years.
Conditions have generally been dryer during the summer/fall and wetter in the winter/spring. By the 2050’s, a 1-in-20 year storm will likely become a 1-in-10 year storm.iv
How Will Our Buildings be Affected?
What do warmer temperatures and an increase in precipitation mean for our buildings and properties?
Extreme Weather Events
Warmer temperatures create more energy in the atmosphere which subsequently absorb more moisture. This increase in atmospheric energy and moisture will increase the frequency and intensity of extreme weather. More frequent and intense extreme weather events including severe thunderstorms, tornados, hail, hurricanes and ice storms will cause major damages to non- resilient building components.
As warmer air can hold more moisture, more frequent and intense precipitation events are expected. Intense rainfalls will increase the risk of flooding of basements, parking garages, and buildings in low lying areas.
With more intense and frequent rainfalls, leaky buildings will become more prevalent, especially with existing and aging buildings. Wetter building interiors will cause an array of issues including damage to interior finishes, deterioration of structural components (wood rot, metal corrosion, concrete fractures) and mould.
Intense Snow and Ice Storms
Higher summer and spring temperatures will delay cooling temperatures in the fall resulting in a later emergence of ice cover on the Great Lakes. While less total snow and ice cover is expected, warmer and ice free lakes will fuel heavy “lake effect” rain, snow and ice storms. High snow and ice loads may cause catastrophic structure failures if our buildings are not properly designed and maintained. Ice storms will cause power outages that may leave buildings without electricity for extended periods.
Accelerated Building Deterioration
Increases in day-to-day weathering processes including wind-driven rain, freeze-thaw cycles and wetting and drying will contribute to premature deterioration of the building exterior (walls, windows, doors and roofs) and structure (concrete, steel, wood, masonry). Decreases in building component lifespans will particularly affect capital plans and reserve funds.
Warmer temperatures in the winter months will create more frequent freeze-thaw cycles as the temperature rises and drops above 0°C. Additional freeze-thaw cycles in combination with wetter conditions lead to premature aging of concrete, brick, stone and masonry via fractures and spalling.
The concentration of airborne components such as carbon dioxide (CO2) in the atmosphere are increasing at an alarming rate. Carbon dioxide causes adverse chemical reactions in concrete that results in the embedded reinforcing steel corroding and concrete fracturing. This is exacerbated by our aging building stock and warmer and wetter weather conditions.
Warmer and longer summer months will place greater stress on building cooling systems. Cooling equipment may not be able to keep up to future cooling demands and leave residents uncomfortable and vulnerable to adverse health risks. More stress on cooling systems will cause
Are You Ready?
The issue of whether Canadians should focus on climate adaption is no longer a question – climate change is occurring already and we are seeing the impact. Given the size and importance of our building stock, it’s important that building owners and asset managers are aware of the impacts of climate change and that they are empowered with the knowledge to help their buildings adapt to a changing climate. Strategies for building resilience in new and existing buildings are being developed that will enable buildings to mitigate risk and better resist the effects of climate change. We’ve all heard it before: ‘failure to plan is planning to fail’, and this statement certainly holds true here. The effects of climate change can be effectively managed with proper planning. Stay tuned for future articles where we will identify risk areas and detail resiliency strategies.