The spread of air-conditioning in hot countries is set to create a huge increase in demand for electricity, threatening efforts to curb greenhouse gas emissions, according to the International Energy Agency, the watchdog backed by consuming countries. Over the next 30 years, air-conditioning could increase global demand for electricity by the entire capacity of the US, the EU and Japan combined, unless there are significant improvements in the efficiency of the equipment, the IEA warned.

In a report released on Tuesday, the agency urged governments to use regulations and incentives to improve the efficiency of air-conditioning units, to avoid a surge in demand that could put strains on energy supplies and increase greenhouse gas emissions.  Fatih Birol, the IEA’s executive director, said: “This is one of the most critical blind spots in international energy policy.” Air-conditioning has had an enormous effect on the quality of life in hot regions, but its use is unevenly distributed around the world. About 90 percent of homes in the US and Japan have air-conditioning, compared with about 7 percent in Indonesia and 5 percent in India.