Risks/impacts of climate change

The Climate Change Master Plan is the City’s overarching framework to reduce greenhouse gas emissions and respond to the current and future effects of climate change.

The plan aims to take unprecedented collective action to transition Ottawa into a clean, renewable and resilient city by 2050. City Council has adopted short, mid, and long-term greenhouse gas reduction targets based on 2012 levels:

• Reduce emissions from the community by:
  • 43 per cent by 2025
  • 68 per cent by 2030
  • 96 per cent by 2040
  • 100 per cent by 2050

• Reduce emissions from City operations by:
  • 30 per cent by 2025
  • 50 per cent by 2030
  • 100 per cent by 2040

Guiding Principles

The Climate Change Master Plan is guided by the following principles:

• Responsibility - everyone has a responsibility to manage energy consumption and to mitigate risks
• Collaboration – all levels of government, utilities, stakeholders, and the broader community must work together to effect change and develop joint solutions
• Municipal leadership – the City needs to take a lead role to ensure an integrated and comprehensive approach across the corporation and the community
• Coordination – all the City’s long-term plans need to be coordinated to ensure a strategic and harmonized approach
• Equity and inclusion – all decision-making processes must incorporate equity and inclusion considerations

Priority Actions

The Climate Change Master Plan identifies eight priority actions for the next five years (2020-2025):

1. Implement Energy Evolution
2. Undertake a climate vulnerability assessment and develop a climate resiliency strategy
3. Apply a climate lens to the new Official Plan and its supporting documents
4. Apply a climate lens to asset management and capital projects
5. Establish a carbon budget and accounting framework and explore the feasibility of including embodied carbon
6. Explore carbon sequestration methods and the role of green infrastructure
7. Encourage community action though education, incentives, support and advocacy to senior levels of government
8. Develop a governance framework to coordinate stakeholder efforts and mobilize the community

Reporting

Staff provide an annual status update on corporate and community greenhouse gas emissions, progress towards the targets and the eight priority actions to the Standing Committee on Environmental Protection, Water and Waste Management.

• 2023 Climate Change Master Plan Progress Report [ 1.754 MB ]
• 2021 Climate Change Master Plan status update
• 2020 Climate Change Master Plan status update

Staff will develop key performance indicators to further track progress being made to achieve Ottawa’s greenhouse gas reduction targets.

Climate Change Master Plan [ 588 KB ]

Ottawa is experiencing warmer, wetter and more unpredictable weather. On average, summers are getting hotter and winters less cold. While average total annual precipitation (rain and snow) has increased, it varies greatly both in terms of where and when it falls. Overall, Ottawa’s weather is becoming more variable and unpredictable, and we have experienced extreme heat, wind, rain and snow in recent years.

Some examples of extreme weather events in Ottawa include:

• Five successive ice storms in January 1998, which caused massive damage to trees and electrical infrastructure causing widespread power outages and a shutdown of activities across Ottawa and the region for several weeks. The ice storms was the second most expensive natural disaster in Canadian history.
• Over 50 cm of snow in February 2016, which caused closures throughout the city and set a new record for the biggest snowfall in a single day
• Significant flooding along the Ottawa River in the spring of 2017 and 2019 resulted in extensive property damage and health concerns
• Tornadoes in 2018 and 2019 caused extensive damage to property and power outages.
• A prolonged extreme heat event that lasted six days in July 2018. On Canada Day, at the hottest time of the day, humidex levels made it feel like 47 degrees Celsius.
• The Ontario-Quebec derecho in May 2022 that killed 10 people, caused widespread property damage and left hundreds of thousands of people in Ottawa without power for several days. The storm is the sixth most expensive natural disaster in Canadian history.

Climate science tells us that these trends will continue in the next decades. The City, in partnership with the National Capital Commission and Environment and Climate Change Canada, worked with climate scientists to develop climate projections for the National Capital Region. Climate projections use climate science and modelling to predict future changes in temperature, precipitation, wind and extreme weather. The study looked at projected changes until the year 2100.

What will Ottawa's climate look like in the future?

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

Temperature

• Average annual temperature will increase by 3.2 degrees Celsius
• 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
• The number of days below -10 degrees Celsius will decrease by 35 per cent

Seasons

• Spring will start two weeks earlier
• Fall will start three weeks later
• Winter will be shorter by five weeks
• Winter freeze-thaw events will increase by 33 per cent

Precipitation

• Precipitation will increase in spring, winter and fall by eight per cent
• The maximum daily precipitation will increase by 14 per cent
• Annual snowfall will decrease by 20 per cent

Extreme events

• Possible increases in freezing rain
• Warming favours the conditions for storms, tornadoes and wildfires

The rate and extent of climate change will depend on future global greenhouse gas emissions. Significant global action is required to reduce emissions below the high emission scenario.

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

The Climate Projections for the National Capital Region study was developed in partnership with the National Capital Commission and Environment and Climate Change Canada. It uses advanced climate science modeling to predict changes in temperature, precipitation, wind and extreme weather until the year 2100. 

• Executive Summary – provides a summary of the study and its key findings
• Volume 1 – provides an overview of the project methodology, findings and implications. It includes results and interpretation for key climate indices.
• Volume 2 – provides plots and tabular data for all the climate indices.

A complete and updated version of the datasets presented in this report is available at Open Ottawa:

• Appendix G – Table of Climate Indices
• Table 2.1 Projections for Extreme Precipitation Based on Multiple Methods
• NetCDF files for the climate indices

The online dataset includes Excel versions of the results in Appendix G and Table 2.1 as well as NetCDF files with more detail than the report (for example, indices calculated for each model and cell). Additional details on the data are also provided on Open Data (for example, model names for each index). Any minor updates to the data sets will be added to Open Ottawa. Please note there may be minor discrepancies between Open Ottawa and the report. If this occurs, the Open Ottawa version should be used.

Impacts of a changing climate

Climate change will impact us all in our daily lives in several ways. For example, more heat waves will increase heat related illnesses, especially for the most vulnerable. Shorter, warmer winters will negatively impact winter recreation. With increased extreme weather events we could see more damage to homes, power outages and strain on emergency services.

It will also impact the way the City operates and plans. Shifting freeze-thaw cycles can damage roads and other infrastructure and more intense rainfall can overwhelm sewer systems and increase the risk of flooding.

There will likely be some positive impacts too. Longer warmer seasons could benefit agriculture and construction. However, warmer weather and changing precipitation patterns will affect ecosystems and may increase conditions for diseases such as Lyme’s disease and West Nile virus.

The impacts of climate change will be looked at in further detail as a part of the climate vulnerability assessment.

City departments work together to understand and reduce the impacts of climate change. Current climate resiliency initiatives include:

• Environmental health warning and response programs to reduce illnesses and deaths associated with extreme heat and humidity, cold weather, and poor air quality.
• An Emergency Management Plan to prepare and respond to the needs of the community during a major emergency, while still ensuring continuation of essential services
• Applying a climate lens to the New Official Plan and its supporting documents to build energy and climate resiliency into future growth and development. The preliminary policy directions recommend climate change mitigation and adaptation policies throughout the plan.
• Using urban heat island maps to better understand what areas are impacted by hot weather, and to inform policies that will reduce the urban heat island effects to better protect public health.
• Applying a climate lens to asset management and capital projects to build resiliency of existing infrastructure.
• Building our infrastructure to be resilient in future climate conditions such as extreme weather, greater rainfall and higher temperatures. For example, the City’s wastewater treatment plant is being upgraded to permit the plant to operate independent of the utility grid, using power produced on site to so it can remain operational in the event of a sustained power failure.
• Growing Ottawa’s urban forest and making it healthier, more diverse and resilient through the Urban Forest Management Plan.

Flood risk management

• Every year the City activates a dedicated Spring Freshet Task Force to monitor the potential for spring floods and respond accordingly.
• The City works with Conservation Authorities to take preventative steps to protect homes from the spring snowmelt or freshet. This includes blasting ice on some sections of the Rideau River and flood monitoring and warning systems. The City also clears debris from storm water drains to prevent overland flooding.
• Designing stormwater infrastructure to accommodate increased flows and protect the Ottawa River through the Ottawa River Action Plan. For example, the Combined Sewage Storage Tunnel will reduce the frequency of sewage overflows entering the Ottawa river during storms.
• Providing grants to homeowners to reduce the risk of flooding through the Residential Protective Plumbing Program.
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• Updating floodplain mapping and community risk profiles to better understand and reduce potential risks from both riverine and urban (basement or overland) flooding. This interactive flood plain map shows three different flood events: a large flood event (1 in 50-year), regulatory flood event (1 in 100-year) and a more extreme flood event that could occur with climate change (1 in 350-year).
• Encouraging and supporting residents to take action on their property to reduce harmful impacts of rainwater run off through the Rain Ready Ottawa pilot program.

There are several things you can do to become more resilient to the impacts of changing weather patterns and extreme events. Find out what you can do to prepare for a changing climate.

Contact the climate change and resiliency team

If you have any questions or comments about climate change in Ottawa please email climatechange@ottawa.ca

If you would like to receive updates on how you can take action and other climate change news subscribe to the climate change e-newsletter.