(CNN) Forget Brexit -- when Queen Elizabeth was snapped in a photo op with Britain's new Prime Minister this week amid record temperatures, all anyone could talk about was her Dyson fan pictured in the background.

"The Queen must be feeling the heat ... I guess there isn't any air con in #BuckinghamPalace," one Twitter user wrote, remarking on the silver fan sitting at the foot of the Queen's gilded armchair.

And, while there was some speculation that the fan's cameo role might be product placement for prominent Brexiteer James Dyson, the overwhelming reaction was: The Queen, she's just like us -- trying to stay cool.

For many in Europe, that has been no easy task, as a scorching heat wave set record temperatures in Belgium, Germany and the Netherlands in recent days.

Cities aren't designed to cope

The reason? Many European cities, including London, are not designed to deal with this sort of heat. Air conditioning (AC) is uncommon in homes across Europe, which has historically had a temperate climate, nor is it widespread on public transportation systems.

An elderly woman shelters from the hot sun with a newspaper, in Milan, Italy.

Those infrastructure gaps were all too apparent in London on Thursday, when railway authorities warned that train tracks might buckle in the heat, while passengers braved stifling underground carriages. Photos of a shirtless passenger and another person who brought a plug-in fan on their journey were doing the rounds on social media, underlining the desperate state of affairs.

Less than 5% of all European households are air-conditioned, compared with more than 90% in the United States, according to the International Energy Agency (IEA). But analysis by the same agency suggests that will change rapidly over the next three decades, with air conditioning set to become one of the top drivers of global electricity demand.

And while that shift will benefit the wellbeing and productivity of many around the world, it will bring its own problems: AC units guzzle electricity and vent hot air, making the outside temperature even higher, and, worse still, refrigerants used in the units contribute to global warming.

People enjoy the hot weather at a beach in Bournemouth, UK.

With an estimated 1.6 billion electric air conditioning units around the world -- a number expected to triple by 2050 -- cooling technology could release enough greenhouse gas emissions into the atmosphere to cause temperatures to rise by 0.5 degrees Celsius by the end of the century, according to Rocky Mountain Institute.

Back to the drawing board

That rapid growth, and its potential to wreak havoc with our environment, is why scientists, architects and urban planners are scrambling to develop other ways to cool buildings, streets and people.

Creating more parks, green roofs and vertical gardens is one way to bring some relief. According to the UK House of Commons Environmental Audit Committee, the surface temperature in an urban green space can be 15 to 20 degrees Celsius lower than that of the surrounding streets, which makes the air temperature 2 to 8 degrees cooler.

Water is another favorite -- mist showers, fountains and reflective pools all bring the temperature down.

A boy cools off under a public water spray on the bank of the Seine river in Paris.

Awnings, overhangs, porticos and simple shutters can also help offset solar heat gain, by preventing light from getting inside. Covered open-air corridoors, ventilated roofs, fiber-glass insulation, the use of natural materials and the manipulation of a building's orientation can also offer alternative sources of ventilation.

And these designs are getting increasingly more inventive. London-based architecture firm Ahr covered a skyscraper in Abu Dhabi in dynamic flower-shaped shutters that change shape depending on the time of day. As the screens fold and unfold in response to the sun's movement, they reflect up to 50% of the light and significantly reduce the need for artificial air conditioning.

Bioclimatic architecture , which employs these energy-saving techniques and could make AC units redundant, is nothing new. Before the 20th century, the technique was the norm and is still visible today in vernacular buildings from Spanish farmhouses to traditional Chinese village homes.

But with the invention of AC by US engineer Willis Haviland Carrier in 1902, bioclimatic solutions fell out of fashion. Today, cooling systems account for 37% of global building energy consumption, according to the IEA , which predicts that AC use will be the strongest driver for electricity consumption in buildings by mid-century.

People cool off next to the fountains at the Louvre Museum in Paris.

Climate apartheid

Many of these changes will take place in some of the world's least developed countries, which also happen to be among the hottest. Nearly 2.8 billion people live in countries where the daily average temperature is more than 25 degrees Celsius (77 Fahrenheit), but less than 10% own an AC unit (that's projected to be 75% by 2050 ). These are also people who are being hit hardest by the effects of climate change.

An alarming report from the United Nations , released last month, suggested that the world is facing a "climate apartheid" between the rich, who can protect themselves in the face of rising temperatures, and the poor, who are left behind.

"We risk a 'climate apartheid' scenario where the wealthy pay to escape overheating, hunger and conflict while the rest of the world is left to suffer," said Philip Alston, the UN Special Rapporteur on extreme poverty and human rights.

The UN also warned that simply slowing down the rise in temperatures, as outlined by the 2015 Paris Agreement, won't be enough to save the millions who are already suffering.

For those across Europe who got a taste of that pain this week, coping with the heat meant trying creative cooling solutions.

Authorities activated emergency plans that include setting up public cooling rooms and extending hours at swimming pools and parks.

People sunbathe and cool off at the Trocadero Fountains next to the Eiffel Tower in Paris.

But in cities like London, many swimming pools couldn't cope with the volume of people -- resulting in long lines with hours-long waits, while others had to shutter completely.

Still, there are some signs that countries are getting better at handling heat waves, even without air conditioning.

After a 2003 European heat wave killed a staggering 14,000 in France alone, authorities devised a plan to avoid such a loss of life again.

Paris implemented a special heat plan, designed to give its inhabitants relief. The city set up public cooling rooms in municipal buildings, put mist showers in the streets and kept parks and swimming pools open longer than usual.

"Since 2003, heat wave plans have improved from year to year with experience of precautionary measures to be taken," French Health Minister Agnès Buzyn said Thursday.

"We now have the feeling that, in collective places, prevention messages are well known."