Most of the world will have air conditioning in their homes, workplaces and cars within 20 years, requiring thousands of power stations to be built and potentially accelerating climate change, energy experts say.
As temperatures shatter records worldwide in 2016, demand for the technology is exploding.
"Globally, 2016 is poised to be another record-breaking year for temperatures. This means more air conditioning. It is becoming an air-conditioned world," says Lucas Davis, an energy economist at the University of California in Berkeley.
"The growth in air conditioning has been staggering. China is the sweet spot. The number of households that have it has doubled in five years. Every year, 60 million more units are being sold there."
As large developing countries such as India, Mexico, Indonesia and Brazil grow richer, staying cool may come to be seen as a necessity and not a luxury, leading to severe energy shortages and major environmental stress, says Davis.
"Air conditioning is wonderful. As people are coming out of poverty, they buy a TV, then a fridge, then a car and air conditioning. There are a lot of hot places where people are getting richer," he says.
But Davis, who expects nearly all households in warm countries to have air conditioning within 20 to 30 years, warns that the extra energy needed will be dramatic and could have huge consequences for global warming. "We are talking about hundreds of new power stations having to be built in China alone over the next 20 or 30 years," he says.
His research is backed by the US government's Lawrence Berkeley National Laboratory, where researchers have calculated that 700 million air- conditioning units are likely to be installed worldwide by 2030 and 1.6 billion by 2050.
Sales in Indonesia, Brazil and India have been growing by as much as 15pc a year, it says.
Technologists say that it's not just warm countries switching from fans to air conditioning.
"Offices, hospitals, shops and homes... are all using air conditioning as buildings fill with computers, televisions and other heat-generating machines," says a spokeswoman for the Institute of Refrigeration.
In addition, she says, better insulation in new buildings traps heat and it is too noisy in cities to have windows open.
Cooling systems may already account for about 10pc of electricity consumption in the UK, says the UK Building Research Establishment. It estimates that 65pc of office space and 30pc of retail space was air conditioned in 2012.
The UN's climate change body, the IPCC, has projected that global air conditioning energy demand will grow 33-fold - from 300 terawatt-hours (TWh) in 2000 to more than 10,000TWh in 2100, with most of the growth coming in developing economies.
But in a world already warming because of fossil fuel emissions from oil, gas and coal, demand for air conditioning and refrigeration is seen as one of the greatest accelerants of climate change.
Concern is also mounting over a class of chemicals that is widely used in refrigerants and air-conditioning units. Hydrofluorocarbons (HFCs) - which have largely replaced CFCs, which were found to damage the ozone layer - are potent greenhouse gases.
Although they are far less significant today than CO2 for global warming, if the numbers of refrigeration and air-conditioning units explode as expected, they could add to the problem.
"The data is poor, but one estimate suggests that refrigeration and air conditioning cause 10pc of global CO2 emissions - three times more than is attributed to aviation and shipping combined - through energy consumption and leaks of HFC refrigerants that are themselves highly potent greenhouse gases," says one expert.
"As climate change increases outdoor temperatures, air conditioning will more often be used to maintain comfortable indoor conditions. Climate change is expected to stimulate installation of air conditioning in buildings that would otherwise not need air conditioning."
Policymakers met recently in Vienna to agree to phase out HFCs, but some countries are nervous about the extra cost of changing to alternative refrigerants. Researchers in India have estimated it could cost the country tens of billions of dollars.