A Google News search for "heat waves" turns up droves; this week, there's the "unusual" one sweeping Western Europe, the one "scorching" the Bay Area with triple digit temperatures, the "brutal" one in Pakistan that left 1250 dead, and the one that "shattered" records in the Pacific Northwest.
That's just right now, at the time of writing; together, they're a snapshot of a heat waving world. But there's little we should consider unusual about these brutal scorchers shattering records; they've become fairly routine on our 400 ppm planet. Just weeks before, a heat wave that hit India killed more than 2,300 people; it was one of the five worst in recorded history. That another came along and did comparable damage to its next-door neighbor just weeks later pretty powerfully elucidates the scope of the coming crisis.
As if cued by the tragedy, the United Nations also proposed its first-ever heat wave warning system this week. The Heat-Health Warning System, as outlined in a 100+ page document, recommends nations take a number of actions to warn their populations of heat waves and brace them for their impacts, including forecasting for high temps that may include humidity, determining their regions' heat-stress thresholds, creating a system of alerts for notifying the public of incipient heat, and building "real time public health surveillance systems."
The World Health Organization and the World Meteorological Organization, the UN agencies behind the report, have essentially concluded that climate change is increasing the frequency and severity of the heat waves—a phenomenon it says doesn't get as much attention as other more destructive weather events—and that action is becoming urgent.
"Heatwaves are a dangerous natural hazard, and one that requires increased attention," the authors write in the report's foreword. There's no universal definition for a heat wave, but are typically regarded as instances of prolonged periods of heat and/or humidity lasting three or more days. "They lack the spectacular and sudden violence of other hazards, such as tropical cyclones or flash floods, but the consequences can be severe."
Severe—and widespread. A 2013 study published in Environmental Research Lettersfound that the regions of the world that would experience extreme heat could double by 2020, and quadruple by 2040. That is if climate change continues apace, which, at least over the last two years since then, it has. "In many regions, the coldest summer months by the end of the century will be hotter than the hottest experienced today," one of that study's authors, Dr. Dim Coumou, told the environmental news organization Climate Central at the time, "that's what our calculations show for a scenario of unabated climate change. We would enter a new climatic regime."
We're certainly entering that: 14 of the 15 hottest years ever recorded have occurred during the 2000s. Last year was the hottest year on record. This year is shaping up to be another one. As the baseline temps climb, so does the propensity for extreme highs—the heat waves now ushered in are poised to become longer, more intense, and, probably, deadlier. And thanks to the heat island effect, it gets hottest in cities, which, of course, are rapidly expanding.
"Cities are growing fast, and they tend to be considerably hotter than surrounding areas," Dr. Diarmid Campbell-Lendrum, WHO's chief of Climate Change and Health said upon the release of the UN report. "Populations are also aging, with more people suffering pre-existing conditions which exacerbate heat stress."
The UN hopes to add heat waves to the ever-expanding list of threats that governments, city planners, designers, and citizens will have to take into account when preparing for the warming future. "It is becoming more and more important for countries to address the growing problem," Campbell-Lendrum said. And how that gets done can vary dramatically, which is why the UN has tried to standardize its suggestions into a Heat-Health Warning System that any nation can use. "The definition of a heatwave is very location-specific. For instance, 32 to 34 degrees celsius may be extremely hot for Geneva but might not be so for Delhi."
As prolonged periods of intense heat become the norm in many places—many with public health institutions far less prepared than London's—a standardized system of best practices could help limit the damage. The surest palliative would be beating back the climbing temps by reducing emissions in the first place, of course, but the 21st century is increasingly looking like the age of adaption. Best brace ourselves for the heat.