The world is getting warmer and cities in particular are sizzling. Now an impressive new study shows that 13,115 cities around the world are not only hotter than in the past, but there are more severely hot and humid days than ever before. The number of days in which urban dwellers are exposed to extreme, and possibly deadly heat, has tripled since the 1980s.
Extreme heat is considered to be around the equivalent of 106 degrees Fahrenheit on the so-called “real feel” heat index. That’s the point at which most of us find it tough to function outdoors for long. In worst case scenarios, a person can develop heat stroke. Those who are already unhealthy or have underlying conditions may become sick, even die.
The reason for this boost in sweltering days — affecting almost a quarter of the population worldwide — is a combination of two factors, a recent Columbia University study finds: rising temperatures and an increase in the number of humans living in cities. Urban population growth alone is responsible for two-thirds of the heat spike, while actual warming contributed a third, depending upon the region and city.
The number of days in which urban dwellers are exposed to extreme, and possibly deadly heat, has tripled since the 1980s.
This isn’t just a matter of being a little uncomfortable on a few hot days. Weather like this can have serious health and economic consequences. “It increases morbidity and mortality,” the study’s lead author, Cascade Tuholske, a postdoctoral researcher at Columbia University’s Earth Institute, said in a statement. “It impacts people’s ability to work, and results in lower economic output. It exacerbates pre-existing health conditions.”
Using a combination of infrared satellite imagery and readings from thousands of ground instruments to determine the maximum daily heat and humidity in cities from 1983 to 2016, researchers came up with what they call “person-days” spent in these boiling conditions. They matched weather data with statistics on the cities’ populations over the same period.
In general, they found that the hottest cities around the world tended to be in lower latitudes. The city where heat affects the human population most was Dhaka, the rapidly growing capital of Bangladesh.
The quicker someone is cooled down, the better their chances for a good recovery.
It’s worth noting this data do not take into account this past summer when there was record heat in the Northwest, as well as southern Canada. Hundreds of people perished as a result of rising temperatures.
This isn’t the first study to document an increase in dangerous heat in urban populations worldwide, but the new study adds nuance to the picture. Specifically, it points to just how many people are affected in each location and how much the population versus the climate is responsible for the increase in heat. The hope is that urban planners can use this information to create ways to adapt to these beastly temperatures.
Visit our feature article on heat stroke to read what an emergency room doctor says you should do if you or someone nearby is overcome by the heat. Here are a few tips on avoiding heat stroke from that story:
- Be careful when exercising or exerting yourself in the heat, especially if the humidity is high.
- Prevention is very important. If you must exercise, then drink plenty of fluids and take fluids with you while exercising or working.
- At the first sign of trouble — weakness, cramps, nausea or vomiting — STOP exercising, find a cool place and drink fluids. If you don't feel better soon, seek urgent medical attention.
- If you come across someone who seems to be affected by the heat, call for help and try to cool them down with water sprays and fanning, while waiting for the ambulance.
- The quicker someone is cooled down, the better their chances for a good recovery.
- Prevention is key. Think about your elderly neighbors and friends in the hot weather. Ensure they have access to a method of cooling, and plenty of fluids.
- Don't forget about children outside playing. They need plenty of fluids throughout the day.
- And, finally, pets can get heat illness too. Make sure they have access to a shaded area and to a plentiful supply of fresh water.