Climate Resiliency Strategy

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Ottawa’s climate is changing. Overall Ottawa will become much warmer and wetter over the coming decades, with more extreme heat days, heavy rain and extreme weather events like severe winds, floods or winter storms. The City is developing a Climate Resiliency Strategy to guide how Ottawa can prepare for and respond to the anticipated impacts of changing climate conditions.

The Climate Resiliency Strategy is one of eight priorities of the Climate Change Master Plan.

Taking action on climate change requires reducing greenhouse gas emissions while also ensuring Ottawa is prepared for the impacts of a changing climate. Energy Evolution is the City’s strategy to reach zero greenhouse gas emissions by 2050. The Climate Resiliency Strategy focuses on getting Ottawa ready for a changing climate. Learn more about Energy Evolution and what you can do to reduce your greenhouse gas emissions.

What will Ottawa’s climate look like in the future and what are the risks?

Overall Ottawa will become much warmer over the coming decades, with more heavy rain and more extreme weather events. Find out more about how we expect Ottawa’s climate to change and the impacts this will have:

Get involved and have your say

The draft climate resiliency strategy, Climate Ready Ottawa, is now available for public consultation. You can share your feedback by:

Find out more about Climate Ready Ottawa and how to have your say.

A summary of how we incorporated feedback from previous engagements is available in the 2023 What We Heard Report.

Subscribe to the climate change e-newsletter to receive updates on the Climate Resiliency Strategy and other climate change initiatives.

Ottawa’s climate is changing. Overall Ottawa will become much warmer and wetter over the coming decades, with more extreme heat days, heavy rain and extreme weather events like severe winds, floods or winter storms. The City is developing a Climate Resiliency Strategy to guide how Ottawa can prepare for and respond to the anticipated impacts of changing climate conditions.

The Climate Resiliency Strategy is one of eight priorities of the Climate Change Master Plan.

Taking action on climate change requires reducing greenhouse gas emissions while also ensuring Ottawa is prepared for the impacts of a changing climate. Energy Evolution is the City’s strategy to reach zero greenhouse gas emissions by 2050. The Climate Resiliency Strategy focuses on getting Ottawa ready for a changing climate. Learn more about Energy Evolution and what you can do to reduce your greenhouse gas emissions.

What will Ottawa’s climate look like in the future and what are the risks?

Overall Ottawa will become much warmer over the coming decades, with more heavy rain and more extreme weather events. Find out more about how we expect Ottawa’s climate to change and the impacts this will have:

Get involved and have your say

The draft climate resiliency strategy, Climate Ready Ottawa, is now available for public consultation. You can share your feedback by:

Find out more about Climate Ready Ottawa and how to have your say.

A summary of how we incorporated feedback from previous engagements is available in the 2023 What We Heard Report.

Subscribe to the climate change e-newsletter to receive updates on the Climate Resiliency Strategy and other climate change initiatives.

  • Climate Ready Ottawa

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    The draft climate resiliency strategy, Climate Ready Ottawa, is now available for public consultation. Climate Ready Ottawa identifies actions to address the top risks facing Ottawa and prepare for a much warmer, wetter and unpredictable climate.

    Climate Ready Ottawa builds on the Climate Projections and Climate Vulnerability and Risk Assessment. It has been created collaboratively with all City departments and with input from the community. The summary of Climate Ready Ottawa provides an overview of the visions, principles and framework for the strategy.

    The strategy is split into five main themes:


    Climate Ready Ottawa is a long-term strategy that will guide action and investment that transition Ottawa to a resilient city by 2050. Once input has been provided on the long-term strategy, a short-term implementation plan that prioritizes specific actions will be developed. Although the City has many initiatives underway, Climate Ready Ottawa identifies new policies, programs and actions to build Ottawa’s resiliency to a changing climate.

    Preparing for climate change will require everyone to take action. Climate Ready Ottawa identifies actions that support individuals, communities, businesses and organizations, as well as where more support is needed from other levels of government.

    Survey

    Have your say on the draft strategy by completing the survey by May 21.

    The results of the survey will help us to:

    • Identify which actions the City should take first.
    • Make it easier for Ottawans to prepare for climate change.


    The survey is split into questions on each of the five themes listed above. We recommend you read the content linked above before completing the survey.

    Open Houses

    Attend an in-person or virtual open house to learn more about Climate Ready Ottawa and how feedback from previous engagements has been incorporated. The open houses will also feature an opportunity to share your feedback and ask questions to the Climate Ready Ottawa team.

    Date, time and location
    Agenda Registration information

    Tuesday April 23, 6:30 – 8:30 pm, City Hall – Jean Pigott Place

    6:45 - 7:30 pm presentation giving an overview Climate Ready Ottawa followed by Q&A

    7:30 - 8:30 pm drop-in session to learn more about Climate Ready Ottawa, share your feedback and ask questions.
    Register

    Pre-registration is not required. Reminder emails will be sent to everyone who registers.

    Thursday April 25, 6:30 – 8:30 pm, Nepean Sportsplex - Richmond Room

    6:45 - 7:30 pm presentation giving an overview Climate Ready Ottawa followed by Q&A

    7:30 - 8:30 pm drop-in session to learn more about Climate Ready Ottawa, share your feedback and ask questions.
    Register

    Pre-registration is not required. Reminder emails will be sent to everyone who registers.

    Sunday April 28, 10 am - noon, Ray Friel Recreation Complex - Fallingbrook Room

    10:15 - 11:00 am presentation giving an overview Climate Ready Ottawa followed by Q&A

    11:00 - noon drop-in session to learn more about Climate Ready Ottawa, share your feedback and ask questions.
    Register

    Pre-registration is not required. Reminder emails will be sent to everyone who registers.

    Tuesday April 30, 6:30 – 8 pm, Zoom

    6:30 - 8 pm presentation giving an overview of Climate Ready Ottawa followed by Q&A Register on Zoom

    If you require any accommodations to fully participate in an open house, please email climatechange@ottawa.ca

  • Resilient communities

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    Ottawa is home to one million residents living in varied communities across a wide geographic region. Climate change will have significant impacts on the livability of our city. Many of the top climate risks relate to:

    • The physical and mental health of residents and visitors
    • Preparing for heat, flooding and extreme weather
    • Negative impacts on food security
    • The impact on the economy, including tourism and farming.


    These impacts come with significant costs to individuals, businesses, organizations, and governments.

    Building equity is a priority. While everyone will be impacted by climate change, certain populations are disproportionally impacted due to increased exposure to climate hazards. For example, they work outside or live in an area prone to flooding or wildfire, or because of the systemic barriers they face.

    We need to build capacity and remove barriers so that everyone can prepare for climate change. This includes those who have less resources or capacity to prepare for, respond to or recover from climate impacts. Building climate preparedness is a shared responsibility and the City can play a role through education, policies and programs.

    Key actions proposed to increase community preparedness for climate change

    • Education and outreach for communities and businesses on how to prepare for and protect from climate risks such as extreme heat, flooding, food security, and tick and mosquito diseases. Targeted outreach to those more at risk, including seniors, newcomers, and people living alone, and in multilingual formats.
    • Support communities and local partners to take action including information and funding for community organizations and social service agencies for climate preparedness programs.
    • Provide more places to cool off such as trees, splash pads, shade structures, drinking water and misting stations. Prioritize them in areas most in need. Explore ways to increase access to cooling in housing for low-income residents, such as through regulations or incentives.
    • Expand flooding education and preparedness programs such as the Residential Protective Plumbing Program and Rain Ready Ottawa to support homeowners to take action to prepare for heavy rains.
    • Develop and strengthen flood preparedness and response plans based on updated riverine flood mapping and forecasting developed by Conservation Authorities. Prohibit new development in the regulatory riverine floodplain and require flood mitigation for development in areas at risk during a more severe riverine flood. Educate homeowners on the steps they can take to reduce riverine flood risks and advocate for increased support from other levels of government for flood mitigation and recovery. Continue to enhance programs that reduce the risk of overland and basement flooding and sewer overflows during heavy rains.
    • Support agricultural and food systems to adapt to changing climate conditions and encourage local food production.

    Resilient Communities Strengthen flood preparedness and response plans for riverine and overland flooding Support communities and local partners to take action through information and funding Expand flooding education and preparedness programs Encourage local food production and support agricultural systems to adapt Add trees, shade structures and places to cool off in areas most at need Education and outreach to communities and businesses on extreme heat, flooding and other climate risks Learn more: engage.ottawa.ca/climate-resiliency


    Additional actions to support resilient communities are covered in the extreme weather preparedness and response, natural environment and parklands, and resilient buildings, transportation and water systems sections.

    Find out more and have your say


  • Resilient buildings, transportation, water systems

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    The City manages approximately $70 billion worth of infrastructure such as roads and pathways, buildings, transit systems, drinking water treatment and sewer systems. This infrastructure is essential to the function and livability of Ottawa.

    Buildings

    Most existing buildings in Ottawa were not designed for our future climate conditions. The health impacts of extreme heat are a particular challenge when buildings lack air conditioning. Buildings will need to be designed and adapted so that they remain habitable during heatwaves and resilient to other climate hazards such as high winds, flooding or power outages. Action is needed for both publicly and privately-owned buildings, especially for buildings that support low income and at-risk populations who are disproportionately impacted by climate change.

    Transportation

    Extreme heat, intense rainfall, freezing rain, freeze-thaw cycles, and extreme weather events all have the potential to damage and disrupt our walking, cycling, transit and road networks. These events increase costs for maintenance, repairs and rebuilding. There are also broader social and economic impacts from health and safety risks, delays, lost productivity and accessibility.

    Water, wastewater and stormwater

    Ottawa’s water-related infrastructure provides critical drinking water, wastewater, drainage and stormwater management services. Climate change will impact the services this infrastructure provides. For example, stormwater and drainage systems can be overwhelmed by the increased amount and intensity of rainfall, and drinking water and wastewater systems can be at risk during power outages.

    We need to improve the resiliency of the transportation network, buildings and water, wastewater and stormwater systems so they can continue to provide services in future climate conditions. The City can also play a role in supporting individuals to prepare and protect private buildings from the impacts of climate change. Trees, rain gardens and porous and reflective surfaces such as cool or green roofs can also help to reduce the impacts related to increased rainfall and extreme heat.

    Key actions proposed to build the resilience of buildings and infrastructure

    • Protect critical infrastructure from our changing climate including, but not limited to:
      • Flood protection at water treatment plants
      • Back-up power at wastewater treatment plant and pump stations
      • Adapt the LRT and buses to operate in extreme heat, ice and power outages.
    • Build new City-owned buildings and infrastructure to withstand future climate conditions by updating design standards and integrating measures into the Corporate Green Building Policy.
    • Monitor, maintain and renew existing City buildings and infrastructure to address the highest risks and update Asset Management Plans and Long-Range Financial Plans for increased long-term operating and renewal costs.
    • Encourage new privately-owned buildings and communities to be designed and constructed to withstand future climate conditions by integrating measures in Community Design Plans and secondary plans, planning guidelines and the High Performance Development Standard.
    • Prepare for increased rainfall and runoff through the Wet Weather Plan, updated stormwater management requirements for new development and adapting older neighbourhoods. Use nature-based solutions where suitable.
    • Support building owners to become more resilient through education, outreach and incentive programs such as the Better Homes Ottawa Loan Program and the Better Buildings Ottawa Program.
    • Work with partners and other levels of government to support social and low-income housing to become more resilient.
    • Improve the comfort and safety of Ottawans by providing shade, shelter and access to water on sidewalks, bike paths and transit stops.

    Resilient Buildings and Infrastructure Build City buildings and infrastructure for future climate conditions Protect critical infrastructure Integrate resiliency in community design plans and building standards Work with partners to identify funding to retrofit low-income housing Increase shade, shelter on sidewalks, bike paths and transit stops. Learn more: engage.ottawa.ca/climate-resiliency

    Find out more and have your say

  • Resilient Natural environment and parklands

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    The City’s natural areas and parklands are important places to relax, explore, play sports, and have fun. Access to nature is essential for physical and mental health, and cultural connection. Greenspaces also provide lots of co-benefits to people and wildlife. Benefits include clean air, reduced flooding and improved water quality, shade, and habitat for animals and pollinators. These benefits are as essential to the livability and function of our city as roads and sewers.

    Changes to our climate are already affecting our nature and parks. The increased spread of diseases, pests and invasive species is having significant and costly impacts. The Emerald Ash Borer, for example, damaged about 20% of Ottawa’s trees in the last 15 years. Extreme weather is also a major threat to Ottawa’s natural areas. Recent wind and ice storms damaged thousands of trees.

    We all need to take steps to support the adaptation of parks, trees and nature to a changing climate and to protect and expand these areas to ensure they continue to provide benefits to our communities and wildlife.

    Key actions proposed to support resiliency in nature and parks

    • Protect and enhance trees and forests – accelerate tree planting, and protect the health of forests and trees through watering, managing pests and proactive trimming. Support recovery and clean-up after extreme weather and develop a wildland fire mitigation plan.
    • Protect natural areas and ensure everyone has access – continue to build and connect Ottawa’s natural heritage system including protecting, restoring and caring for watercourses, wetlands and groundwater. Identify and manage erosion and unstable slopes.
    • Increase shaded parklands by increasing the number of parklands as well as trees, shade structures or cooling features especially in neighbourhoods that are currently missing these features.
    • Public education and stewardship to raise awareness about tree care and the value of wetlands and greenspace, and support community environmental stewardship programs.

    Resilient Natural Environment and Parks Build and connect Ottawa’s natural heritage through protection, restoration and stewardship Manage erosion and unstable slopes along watercourses Increase tree planting, adjust maintenance and protect forests from pests and wildfire Increase shaded parklands Public education and stewardship programs Learn more: engage.ottawa.ca/climate-resiliency

    Find out more and have your say

  • Extreme weather preparedness and response

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    In the past few years, Ottawa has experienced multiple extreme weather events including flooding, tornadoes, a derecho, ice storms and poor air quality due to wildfire smoke. These events impact people’s health, damage property, and place a huge financial and mental strain on communities and the City.

    The frequency and severity of extreme weather events are expected to increase with climate change, as will prolonged heat waves and the risk of drought. Extreme weather directly impacts communities and worsens many of the inequities that are already present. While the City and its partners have excellent emergency response systems, climate change places a greater strain on both community and City resources. It also highlights the need for greater preparedness by private and non-profit housing and care providers and enhanced support from all levels of government.

    We all need to take steps to prepare for and respond to more frequent and severe weather events and support the most vulnerable.

    Key actions proposed to strengthen extreme weather preparedness and response

    • Increase the capacity of the City to respond to emergencies through training, updating preparedness and response plans, and equipping more emergency reception centres.
    • Provide community education and support on extreme weather preparedness including targeted outreach to flood and wildfire-prone areas. Support community-led emergency planning and volunteer networks.
    • Target support for most at-risk populations including emergency distribution of food, water and medical batteries, and coordinating wellness visits. Advocate to provincial and federal governments for additional support.
    • Work with local partners to create community-based hubs that supplement City reception centres and provide support to residents closer to where they live.
    • Prepare for more power outages with emergency power at reception centres, improved communications, and strategies to restore power quickly for at-risk populations and critical services. Advocate for strengthened preparedness and response plans at privately-owned buildings and long term-care facilities to provide essential power, heat or cooling, and water for up to 72 hours.
    • Support hydro utility efforts to improve electrical grid resiliency through investments in burying power lines, reinforced poles and tree management. Explore on-site power generation and storage to reduce dependency on the electrical grid.

    Extreme Weather Preparedness and Response Support most at-risk populations Enhance public education and support community preparedness plans Work with local partners to provide community-based hubs Increase City capacity to plan for and respond to extreme weather Prepare for more power outages improve communications, back-up power at critical facilities, build grid resiliency, restore power to critical services Learn more: engage.ottawa.ca/climate-resiliency

    Find out more and have your say

  • Cross-cutting actions to build a Climate Ready Ottawa

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    Preparing for climate change requires a shift in how we design and build our city and deliver services. It’s a long-term goal that will need to be incorporated into all the City’s planning and decision making. Continuing to reduce greenhouse gas emissions is also important to reduce the severity of future climate risks.

    The City cannot meet its climate goals alone. Creating a Climate Ready Ottawa will require collaboration with other levels of government, institutions, businesses and community organizations. It will also require a commitment to incorporate health and equity into the design and implementation of programs to ensure those most impacted by climate change are supported.

    Key actions proposed to build a climate resilient Ottawa

    • Adopt a distributed leadership model and build capacity across all City departments to implement Climate Ready Ottawa
    • Continue to work with community partners and other levels of government to share learning and identify opportunities for joint action. Share information and data on climate preparedness and risk reduction publicly.
    • Advocate for increased action by other levels of government for policies, programs and funding that mitigate the risks of future climate conditions and support both City and community action.
    • Continue to embed climate preparedness in key City plans, policies and procurement. Integrate climate risk mitigation into core plans such as Master Plans, Asset Management Plans and Long Range Financial Plans. Continue to track and report on planned investments in climate resiliency, climate risks and mitigation strategies.
    • Continue to advocate for and invest in reducing greenhouse gas emissions to reduce the severity of climate impacts.
    • Develop a funding strategy that considers both short and long-term needs. Identify the costs and benefits of proactive investment in resilient infrastructure over the coming decades and explore ways to leverage funding and partnerships.

    Cross-cutting actions to build a Climate Ready Ottawa Continue to invest in reducing greenhouse gas emissions to reduce the severity of impacts Build capacity across all City departments Explore opportunities for joint action with local partners Develop a funding strategy for early investments and leverage external funds Advocate to other levels of government for policies, programs and funding Embed climate preparedness in City plans and budgets, and track investments Learn more: engage.ottawa.ca/climate-resiliency

    Find out more and have your say

  • Ottawa’s top climate risks

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    The City undertook a Climate Vulnerability and Risk Assessment to identify the top climate risks facing Ottawa. This is the second phase of the Climate Resiliency Strategy development.

    The Climate Vulnerability and Risk Assessment draws on the climate projections developed in 2020 as well as input and expertise from City staff, community partners and the public. It assessed how vulnerable Ottawa is to changing climate conditions and prioritizes where action is most needed.

    The project assessed close to 150 potential climate impacts on health, community well-being, infrastructure, natural environment and the economy. Of these potential climate impacts, 40 priority risks were identified that require action in the next one to three years. These include risks related to higher temperatures and more precipitation, as well as more extreme weather like flooding, severe winds and freezing rain.

    Some of the priority risks include, but are not limited to:

    • Increased heat-related illnesses
    • Increased need for cooling in buildings (especially in community buildings like schools, low-income housing and private long-term care facilities)
    • More invasive species, pests and diseases harming trees, greenspaces, and agricultural production
    • New or intensified disease vectors (for example ticks that carry Lyme disease, or mosquitoes that carry West Nile virus)
    • Increased damage to roads, buildings and other infrastructure from freeze-thaw and freezing rain
    • Flood damage to infrastructure and property from heavy rains and riverine flooding
    • Increased pressures on the City and community services to respond to simultaneous or repeated extreme weather events
    • Reduced access to essential services such as electricity, healthcare, education, food banks and transit during extreme weather
    • Increased pressures on low-income and other disproportionately affected people (mental, physical and financial health)

    More information about these climate impacts is available in the Climate Vulnerability and Risk Assessment report and Appendix D (Climate Vulnerabilities and Risks by Focus Area). A summary of the priority risks is also available.

    The Climate Vulnerability and Risk Assessment was presented to the Standing Committee on Environmental Protection, Water and Waste Management on June 21, 2022 and City Council on July 6, 2022. You can watch the recordings of Committee and Council on YouTube.


  • Ottawa in 2050: Extreme heat

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    Climate change means warmer seasons, more days over 30 degrees Celsius, high humidex and risk of drought. The top risks from extreme heat are dehydration, heat exhaustion and stroke, stressed natural and agricultural areas, limited shared areas and places to cool off, limited air conditioning and too hot for walking, cycling and outdoor activity.


    Ottawa’s climate is already getting warmer. Between the mid-1940s and the mid-2010s the average temperature in Ottawa increased by 1.3 degrees Celsius.

    This trend will continue in the future. Ottawa will be warmer year round, there will be more extreme heat days and less extreme cold days.


    What we are expecting

    By the 2050s, under a high-emission scenario, temperature in the National Capital Region is projected to change in the following ways.

    • Increase in average temperatures in all seasons – the average temperature will increase by 3.2 degrees Celsius.
    • Less cold extremes – the number of days below -10 degrees Celsius will decrease by 35 per cent. That’s a decrease to 46 days per year from the current 71 days.
    • More warm extremes there will be four times as many very hot days over 30 degrees Celsius. That’s an increase to 43 days per year from the current 11 days.
    • Increase in humidex – the number of days with high humidex levels will increase.
    • Drought – more variability in precipitation and risk of drought


    You can find out more details of what to expect in the 2030s and 2080s in the Summary of the Future Climate in Canada’s Capital Region.


    What are the top risks from extreme heat and drought?

    • Increased heat-related illnesses – extreme heat can cause dehydration, heat exhaustion, heat stroke and even death.
    • Less outdoor recreation and active transportation – hotter and more humid summers could lead to a decrease in outdoor recreation and sports and the cancellation of community events.
    • Increased need for cooling in buildings – as temperatures rise, there will be more demand for cooling in the summer which will increase energy costs. Buildings may also need to be retrofitted to add better cooling and ventilation. Community buildings such as churches, daycares or schools may be forced to close temporarily during extreme heat events if they do not have adequate air conditioning.
    • Increased demand for shaded areas and indoor and outdoor recreation facilities to offset heat
    • Impacts on the natural environment – extreme heat and drought place additional stress on our ecosystems. Algal blooms are harmful to human health and will cause no swim advisories.
    • Reduced agricultural yields and increased irrigation – extreme heat and drought create challenging growing conditions and reduce harvest.


    More information about the climate impacts facing Ottawa is available in the Climate Vulnerability and Risk Assessment.


    Who is most vulnerable to extreme heat?

    High temperatures can put everyone at risk, especially those without access to air conditioning. Health risks are greatest for infants, older adults, people who work or exercise outdoors, those with pre-existing health conditions, and people experiencing homelessness.

    Reduced access to recreation could impact the mental health and wellness of individuals and families who could find themselves even more isolated if free/low-cost outdoor activities are cancelled.


    How can you prepare?

    We all have a role to play in preparing for the impacts of changing weather patterns and extreme events. Find out what you can do, what the City is doing and visit the Resource Hub (coming soon) where we have additional resources that can help communities prepare for climate change.


    The Urban Heat Island Effect

    This is a map of the City of Ottawa which is colour coded in increments to show land surface temperature. This map shows that rivers, lakes, greenspaces, parks, natural spaces and light-coloured surfaces (e.g. white roofs) tend to be cooler. Large buildings with dark roofs (e.g. commercial, institutions), large parking lots and artificial turf absorb and retain heat. These areas are referred to as urban heat islands.

    The urban heat island effect occurs when built-up areas are hotter than surrounding areas. Buildings, parking lots and other dark surfaces retain heat and become hotter than nearby greenspaces, water and rural areas. The annual mean air temperature of a city with one million people or more can be one to three degrees Celsius warmer than its surroundings during the day. In the evening, the difference can be as high as 12 degrees Celsius.

    The City of Ottawa in partnership with Ottawa Public Health created two urban heat island maps using satellite imagery from July 18, 2019, a hot day where temperatures reached 27.3 degrees Celsius and the humidex reached 31:


    The colour codes show how surface temperatures ranged from 15 to 38 degrees Celsius across the City. The map shows cooler areas include the Ottawa and Rideau Rivers and their tributaries; the Greenbelt; greenspaces, parks, natural spaces; and light-coloured surfaces including buildings with white roofs. Buildings with dark roofs, such as those found on large commercial and institutional buildings, parking lots and artificial turf show up as hotter areas that absorb and retain heat.

    These maps highlight areas of potential additional risk created by the urban heat island effect. Additional factors that influence an individual’s risk include access to air conditioning at work, school, home and during commutes, if they work or exercise outdoors, their age, and pre-existing health conditions.


    How are these Urban Heat Island Maps being used?

    Heat island maps show us how land use choices affect surface temperature. With temperatures expected to rise by 3.2 degrees Celsius by the 2050s and the number of days above 30 degrees Celsius expected to rise fourfold to 43 days, heat islands worsen the impact of extreme heat events. Extreme heat affects everyone, but certain people are more vulnerable to heat stress, including the very young and old, people who are pregnant, people with existing health conditions, people who work outside, athletes, people who are homeless or precariously housed, and those that don’t have good access to air conditioning.

    Heat island maps can be used to guide policies and planning of the built environment. Strategies to reduce surface temperatures include tree protection and plantings, the use of vegetation on and around buildings and parking lots, and the inclusion of parks and greenspace and reflective surfaces such as light-coloured roofs.

  • Ottawa in 2050: Changing Seasons

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    Climate change means earlier spring, later fall, more free-thaw cycles in winter, fewer days below -10 degrees Celsius and shorter winters with less snow. The top risks from changing seasons are more invasive species, pests and diseases, more cases of tick disease and West Nile virus, reduced winter activities and tourism, damage to roads and buildings from freeze-thaw and impacts to biodiversity and natural areas.

    Average temperatures are increasing across all seasons causing their typical characteristics to change.

    What we are expecting

    By the 2050s, under a high-emission scenario, seasons in the National Capital Region are projected to change in the following ways.

    • Earlier springs – the last day of spring frost will start two weeks earlier
    • Later falls – the first day of fall frost will be three weeks later
    • Shorter winters – winter will be shorter by five weeks
    • Shift in freeze-thaw cycles – winter temperatures will hover around 0 degrees Celsius more frequently in the future. Winter freeze events will increase by 33 per cent
    • Decrease in snowfall – the annual total snowfall will decrease by 20 per cent.
    • Shorter snow season – the first snowfall will be later in the year, and the last snowfall will be earlier. As a result, the number of days with snow cover is projected to decrease from the current 115 days to 72.


    You can find out more details of what to expect in the 2030s and 2080s in the Summary of the Future Climate in Canada’s Capital Region.


    What are the top risks from changing seasons?

    • More invasive species, pests and diseases harming our natural environment and agricultural areas
    • Increase in cases of Lyme disease, West Nile virus and possibly other diseases as extended warmer seasons enable increased tick and mosquito populations. Other disease that are not currently prevalent in our region could also increase.
    • Increased slips and falls in icy conditions from increased winter freeze-thaw.
    • Damage to roads, buildings and other infrastructure from increased winter freeze-thaw and freezing rain, leading to more maintenance requirements and increased risk to users.
    • More pressures on parks and beaches from increased use.
    • Decline of winter tourism and recreation as less snow and warmer conditions mean reduced opportunities for activities such as skating, skiing and snowshoeing.


    More information about the climate impacts facing Ottawa is available in the Climate Vulnerability and Risk Assessment.


    Who is most vulnerable?

    Warmer temperatures put everyone at risk. Outdoor workers and individuals that spend a significant time outdoors are at increased risk of Lyme disease and West Nile virus. Pedestrians are at increased risk of slips and falls due to increased icy conditions, and persons with limited mobility may be more isolated.


    How can you prepare?

    We all have a role to play in preparing for the impacts of changing weather patterns and extreme events. Find out what you can do, what the City is doing and visit the Resource Hub (coming soon) where we have additional resources that can help communities prepare for climate change.

  • Ottawa in 2050: More rainy days and heavy rain events

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    Climate change means more rain in winter, spring and fall, more intense rainfall and more freezing rain. The top risks from more rainfall are frequent river flooding, reduced water quality and erosion, damaged homes, flooded streets, paths and parks and delayed planting and harvesting.


    Ottawa has seen increased rainfall over the past decades, especially in spring and fall. As our climate warms, these trends will continue. There will be an increase in both the amount and intensity of rain, including in winter months.

    What we are expecting

    By the 2050s, under a high-emission scenario, precipitation in the National Capital Region is projected to change in the following ways.

    • Increase in total precipitation (except in summer) – the total amount of precipitation (rain and/or snow) will increase in spring, winter and fall by eight per cent. Rainfall in summer (June – September) will not increase.
    • Wet days will be wetter – although the total annual precipitation will increase, this precipitation will be concentrated within the same number of ‘wet days’. The maximum amount of precipitation that falls in one day will increase by 15 per cent.
    • Increase in freezing rain – the colder months will likely see more freezing rain due to the increase of days around zero degrees Celsius. Freezing rain in spring and fall will likely decrease.


    You can find out more details of what to expect in the 2030s and 2080s in the Summary of the Future Climate in Canada’s Capital Region.


    What are the top risks from more intense rainfall and flooding

    • Flood damage – more intense rainfall can overwhelm sewer systems and increase the risk of flooding in our streets and homes. Riverine and inland flooding can damage or reduce access to roads, transit, pathways, property and other infrastructure. Increased precipitation can also damage and overwhelm stormwater, wastewater and flood protection infrastructure.
    • Mental, physical and financial health – flooding negatively impacts the health of those directly affected. It can also cause mold and contaminate private wells and septic systems.
    • Reduced agricultural yields – more variable rainfall and the risk of flooding create challenging growing conditions and reduce harvest.
    • See additional risks from freezing rain in the extreme weather section below.


    More information about the climate impacts facing Ottawa is available in the Climate Vulnerability and Risk Assessment.


    Who is most vulnerable?

    Some people are at higher risk from increased precipitation. Communities in flood-prone areas may be affected more frequently or severely making it more challenging to prepare and respond to flood events. Lower-income and other disproportionately affected households are particularly vulnerable. Communities that rely on private wells in flood prone areas are more at risk of contamination to their drinking water caused by flooding.


    How can you prepare?

    We all have a role to play in preparing for the impacts of changing weather patterns and extreme events. Find out what you can do, what the City is doing and visit the Resource Hub (coming soon) where we have additional resources that can help communities prepare for climate change.


    Flood plain mapping and climate change

    Flood plain map of Ottawa


    Flood plain mapping identifies the areas that may experience flooding due to rising water levels in a watercourse. An interactive flood plain map which uses flood hazard mapping produced by the local Conservation Authorities in partnership with the City is now available. The map shows three different flood events:

    • A large flood event which has a 2 per cent chance of happening in any given year. Also known as a 1 in 50-year flood
    • A regulatory flood event which has a 1 per cent chance of happening in any given year. Also known as a 1 in 100-year flood.
    • A more extreme flood event that could occur with climate change. Also known as a 1 in 350-year flood.

    The effect of climate change on the magnitude and probability of future flood events is difficult to predict. Local climate projections for the National Capital Region indicate trends of warmer temperatures, increased amounts of rain (including in the winter and spring), as well as more intense rainfall. This can all affect river levels and flows. The 1 in 350-year flood event was selected as an appropriate larger flood event for assessing potential changes in riverine flood hazards and risks due to climate change.


    Purpose and use of flood plain mapping

    Floodplain mapping is critical for the effective management of riverine flood risks through the prevention/mitigation of risks, protection of people and property, and emergency preparedness and response planning. Effective hazard and risk management will often involve a combination of measures. The City, Conservation Authorities, and property owners all have a role to play in flood risk management. As per the City’s Official Plan, for example, any new development in a 1 in 350-year flood area must demonstrate how it will mitigate the risks of more severe flooding.


    How are these maps being used to inform the Climate Resiliency Strategy?

    The 1 in 350-year flood hazard maps are being used to inform the development of the Climate Resiliency Strategy. The maps can be used to identify which communities, parks and infrastructure could be affected by more severe flooding. The information is being used, for example, to inform plans to ensure continued service at the City’s water purification plants and wastewater treatment plant.

    Learn more about flood plain mapping

Page last updated: 17 Apr 2024, 10:00 AM