By Ladd Keith and Sara Meerow
Shocking heatwaves in the U.S. Pacific Northwest and Canada show preparation for climate-driven extreme heat needs work - fast.
Summer just started in the Northern Hemisphere, but cities everywhere have already been impacted by unprecedented extreme heat and must plan for heat resilience now.
The U.S. Pacific Northwest and Western Canadian heatwave from June 26-29 is particularly concerning, as cities in the region are often seen as refuges from heat.
The heatwave shattered previous records by large margins. Most shocking of all was the small town of Lytton in British Columbia, which broke Canadian national records for three consecutive days and reached an astounding 121 degrees Farenheit (49.5 degrees Celsius).
To put that into perspective, the highest temperature recorded in Las Vegas, Nevada, a thousand miles (1,600 kilometers) to the south, is 117F (47.2C).
Extreme heat events like this are increasing in frequency, intensity, and duration due to climate change. In the United States, heatwaves have already increased from an average of two per year in the 1960s to six per year in the 2010s. Heatwaves are also already 3F (1.7C) to 5F (2.8C) hotter due to climate change.
Yet it is not only heatwaves that are concerning. Global average temperatures have already risen 2.2F (1.2C) and pushed cities into new climates.
In addition to climate change, the way cities have been planned and built contributes to the urban heat island effect, which makes cities 7F (3.9C) hotter than surrounding rural and natural areas.
The urban heat island effect is increased by roads, parking lots, and other heat-trapping surfaces as well as waste heat generated by things like vehicles and air conditioning.
The heat severity within cities is inequitably distributed, with lower income, minority, and marginalized residents often living in neighborhoods that are hotter than their wealthier and whiter counterparts.
The combination of climate change and the urban heat island effect has deadly consequences. Heat is the biggest weather-related killer in the United States, and is particularly dangerous to the elderly, those with pre-existing health conditions, and people experiencing homelessness.
Heat is dangerous for all cities but carries particular risk in historically colder cities with less indoor cooling and experience with heatwaves. Early reports of heat-related deaths from the Pacific Northwest heatwave show them already in the hundreds.
In addition to heat-related deaths and illnesses, heat impacts cities’ infrastructure, landscaping, energy and water use, and economies.
Portland’s streetcar was shut down as power cables melted, and roads across the region buckled due to the extreme heat. Heat also compounds other risks such as drought and wildfire. A day after Lytton set the new record high, a fast-moving wildfire destroyed 90% of the town.
Cities must begin planning for heat resilience to increasing heat risk. Heat resilience includes efforts to curb exposure to rising temperatures and prepare for and respond to extreme heat events like the Pacific Northwest heatwave.
Greenhouse gas emissions should be aggressively reduced to prevent heatwaves made even worse by climate change. To limit the urban heat island effect, cities should reduce unneeded asphalt and concrete, increase vegetation by planting trees and greening stormwater infrastructure, utilize cool paving and roofing to better reflect heat, increase the energy efficiency of buildings to reduce waste heat, and conserve undeveloped lands.
For managing extreme heat events, cities should increase heat awareness and information campaigns, provide home weatherization and indoor cooling assistance for lower-income residents, and increase the accessibility of cooling centers that provide refuge in emergencies.
Some of these heat resilience strategies are underway, but cities are not coordinating their efforts across departments or levels of government.
Urban planners and designers largely work in the area of reducing exposure to heat, while public health and emergency management focus on heat management. Cities should coordinate these strategies and ensure they are equitably distributed according to heat risk to avoid worst-case scenarios.
There are signs that some cities are starting to take heat seriously.
Miami-Dade County appointed a chief heat officer and the city of Phoenix created an Office of Heat Management and Response - both the first of their kind in the United States.
While Miami and Phoenix may have the resources to pursue heat resilience, heat is also a threat to smaller towns and rural areas that lack these resources. Support for cities to plan for heat resilience at the regional and national level is essential to ensure emerging best practices are available to all.
The reality is that all cities, regardless of size or location, need to plan for heat resilience now.