Ottawa experienced yet another heat warning at the end of July, we are experiencing heat waves with increasing frequency and intensity due to climate change. Knowing where heat islands are in our cities — and who lives in them — becomes a crucial public health issue.

The urban heat island effect occurs because the closely packed buildings and paved surfaces that make up our cities amplify and trap heat, far more effectively than natural ecosystems and rural areas. These areas are often shaded by trees and vegetation and cooled by evaporating moisture.

This interactive tool shows how your neighbourhood compares to others in your metropolitan area regarding urban temperatures. An analysis of urban temperatures shows that immigrants and people with low income are most likely to live in the hottest urban areas. This is linked to reduced ability to adapt to hotter conditions and high density areas with a lack of surrounding vegetation and green space. This makes them much more vulnerable to heat waves, with deadly consequences.

Heat-related risk and vulnerability in Canadian cities can be reduced through mitigation measures. Whether that’s by adapting homes to protect against and reflect heat, such as the use of air cooling units. Or through larger-scale initiatives, like planting trees and improving access to green spaces and cooling shelters.

Forêt Capitale Forest is working to expand green spaces and tree canopy in Ottawa. By making neighbourhoods more climate resilient, we can also mitigate the negative impacts caused by heat.

However, planting trees or adding green space can trigger unwanted consequences such as gentrification. As these areas become more green and desirable, rents are likely to increase, and current – low income residents could be displaced. This reinforces the trend of who lives in hotter neighbourhoods. A solution is to implement social and housing policies that go alongside greening policies.