I stand on the shore at Kitsilano Beach, watching beachgoers sprawl across the sand as May temperatures soar to 28°C – what would have been considered a July heatwave when I first moved to Vancouver a decade ago. Children dash in and out of the water, their laughter punctuated by complaints about the heat. An elderly man sits beneath a small portable umbrella, fanning himself methodically.
“I’ve lived here since ’68,” he tells me, introducing himself as Gerald. “We used to get maybe a week of this weather in summer. Now it starts in spring and doesn’t quit.“
His observation mirrors alarming new research published in Nature Climate Change showing that human-caused climate change has subjected nearly half the world’s population to what amounts to an extra month of extreme heat annually.
The study, led by climate scientists at the University of Washington and the Climate Impact Lab, analyzed temperature data from more than 200 countries between 1979 and 2024. Their findings reveal that the average person worldwide now experiences 30 additional days of extreme heat compared to what would have occurred without climate change.
“We’re not talking about future projections anymore,” explains Dr. Sarah Chen, a climate scientist at the University of British Columbia who wasn’t involved in the study. “This is happening now, affecting billions of people, with the burden falling disproportionately on regions that contributed least to the problem.”
The research defines extreme heat as temperatures exceeding the 95th percentile of a region’s 1979-1999 temperature distribution – essentially, the hottest 5% of days from that baseline period. What constitutes extreme varies by location, making this definition particularly valuable for understanding local impacts.
For Vancouver, this means days above 27°C are now occurring nearly three weeks earlier in spring and extending two weeks longer into fall than they did in the 1980s.
The consequences extend far beyond discomfort. BC Emergency Health Services reported a 31% increase in heat-related calls last summer compared to the previous five-year average. Following the 2021 heat dome that killed 619 people in British Columbia, health authorities have strengthened early warning systems, but Dr. Chen warns that adaptation measures aren’t keeping pace with the changing climate.
“Heat kills more people than any other weather-related disaster in many countries,” she says. “And the health impacts extend beyond mortality – they include reduced worker productivity, increased violence, and worsening mental health.”
In East Vancouver’s Grandview-Woodland neighborhood, I meet Imran Malik, who runs a small grocery store that lost power three times last summer during peak heat days. Without functioning refrigeration, he had to discard thousands of dollars worth of perishable food.
“Each time it happens, I lose at least a week’s profit,” Malik says, pointing to the new backup generator he purchased after the third outage – an adaptation cost he never anticipated when opening his business eight years ago.
The global pattern shows stark inequities. In South Asia, parts of Africa, and Central America, some communities are experiencing up to 50 additional extreme heat days annually. These regions often have the fewest resources to adapt with cooling infrastructure or revised work schedules.
Walking through Vancouver’s Downtown Eastside, I see firsthand how extreme heat disproportionately affects vulnerable populations. At a newly installed city cooling station, outreach worker Janice Wong helps an elderly man with mobility issues find shade and water.
“People living in SROs without proper ventilation, seniors isolated in apartments, those with chronic health conditions – they’re the ones suffering most,” Wong explains. “And when heat combines with wildfire smoke, which we’re seeing more frequently, the health impacts multiply.”
Climate policy experts emphasize that while the study paints a sobering picture, it also reinforces the urgent need for both mitigation and adaptation measures.
“Every fraction of a degree matters,” says Mark Jaccard, director of the School of Resource and Environmental Management at Simon Fraser University. “Cutting emissions dramatically this decade could prevent that extra month from becoming two or three months by mid-century.”
Back at Kitsilano Beach as evening approaches, the temperature has barely dropped. Families pack up their belongings, red-faced children dragging their feet in the sand. Gerald, the elderly resident I spoke with earlier, prepares to leave too.
“You know what’s strange?” he says, gesturing toward the water. “We used to come here to warm up. Now we come to cool down.”
The rhythm of seasons is changing, stretching summer’s extremes into what once was spring and fall. As I walk home under a still-bright evening sky, I pass newly installed heat pumps on apartment buildings and houses throughout the neighborhood – small symbols of adaptation to a new climate reality that arrived faster than most anticipated.
For nearly half the world’s population now experiencing an extra month of dangerous heat each year, the future is already here. The question remaining is whether we can prevent it from becoming even more extreme.
