Thomson Reuters Foundation, trust.org (TRF)
When the next heatwave hits, what are the cheap, green options to keep the temperature down?
By Megan Rowling
BARCELONA - As heat becomes more extreme on a warming planet, millions more people are switching on air conditioners. But is machine-cooled air the best solution to rising temperatures?
In poorer countries, many families cannot afford air conditioning - although that is changing fast in the cities of emerging giants such as China and India.
Around the world, the number of air conditioners is expected to rise to 1.5 billion units by 2030 from 660 million in 2015.
In some richer, cooler countries like Britain or Finland, air conditioning hasn't traditionally been needed, and most private homes do not have the equipment installed.
But with global average temperatures having risen by more than 1 degree Celsius since pre-industrial times, people are increasingly being jogged out of their physical and behavioural comfort zones, experts say.
"With climate change, we are going to be experiencing higher temperatures more generally - but also more frequent, more intense and longer heatwaves too," said Angie Bone, head of the extreme events and health protection team at Public Health England, a UK government agency.
"The risks of heat can be under-estimated," she said.
Even as their efficiency improves, air conditioners contribute to the problem of global warming, as they need power to run - much of which will be provided by burning fossil fuels in the near term.
So when the next heatwave hits, what are the greener alternatives for staying cool? Here are some ideas:
Barcelona city council, which activated measures to protect residents from heatwaves twice this summer, gives out practical advice, including closing blinds and shutters facing the sun and opening windows at night when the air cools down. Inside the house, rest in cooler rooms, and take a shower or use a wet towel to refresh yourself.
If you don't have fans or any form of cooling equipment, spend at least two hours a day in public places with air conditioning, such as libraries or cinemas.
Don't go out or drive during the hottest part of the day if you can help it. If you must, wear a hat or carry an umbrella. Dress in light-coloured, loose clothing. Avoid physical exercise, walk on the shady side of the street, drink plenty of water, and rest in cool places, says Barcelona city hall.
Health experts agree that those most at risk from extreme heat are the elderly and people with existing health problems, such as heart conditions, high blood pressure and asthma. That's especially true if they live alone. Young children and homeless people are also vulnerable.
"Most of us do know somebody, either in our friends or family or community networks, who may be more at risk and who might just value a bit of extra support when it gets hot," said Bone of Public Health England. During the heatwave that struck Europe in 2003, about 2,000 deaths more than normal were recorded in England and Wales over the hottest 10-day period, mostly among older people in the southeast.
England established a heatwave plan the following year, which recommends telephoning or visiting vulnerable people to make sure they are coping.
The Red Cross is active in getting the message out to the public about how to stay safe in hot weather across Europe - whether by making home visits, handing out leaflets, using social media or putting its experts on TV or radio to give alerts and tips.
Last month, it issued a statement warning of "serious health risks" as south and central Europe experienced the highest August temperatures in more than a decade."It can be dangerous and deadly for people," said Tiina Saarikoski, a senior public health officer with the International Federation of Red Cross and Red Crescent Societies. In France, for example, Red Cross teams handed out water to the homeless in cities and provided information and door-to-door checks on the elderly and isolated.
Before air-conditioning was invented in the early 1900s, architects and ordinary folks built homes using materials with natural cooling properties that were designed to keep out heat - from constructing thick stone walls to putting in small windows facing away from the sun.
In Malaysian villages, traditional "attap" houses - wooden structures on stilts - are still a common sight. There is space for the wind to circulate under the house, which has a cooling effect, while the interior stays dry during floods. The houses have a high-pitched gable roof of "attap", a thatch made from palm fronds, which insulates against heat.
In parts of the world like Mali, where mud has been used to build from about the 13th century, traditional techniques can be seen as outdated and a sign of poverty. But swapping them with modern materials such as metal roofing sheets can make homes far hotter and more uncomfortable.
Green spaces with vegetation and trees, which provide shade and moisture, can help keep people cool - particularly in cities that are often several degrees hotter than surrounding areas due to a prevalence of concrete and glass, high energy use and pollution.
In hot, arid places such as Iran and Morocco, for example, buildings have been historically designed around a central courtyard that provides shade and keeps inhabitants cool. Japanese traditional architecture relies on wood, bamboo and paper, incorporating sliding doors and walls opening onto verandas that overlook landscaped gardens with ponds.
And in Louisiana, elevated "shotgun houses", emblematic of New Orleans, are suited to warm climates because of their long, narrow design, with rooms running front to back, doors aligned in a row and high ceilings - all of which improve air circulation.