Ancient technology and new innovation could help keep us cool

Last September, an epic heat dome settled over the western United States, causing the region’s most severe heat wave on record. In many areas, temperatures soared to triple-digit highs for more than a week. Almost a thousand heat records were broken.

The scorcher is just one example of how heat waves are becoming more intense and longer lasting due to global warming. By 2050, nearly half the world may live in areas where the mercury rises to dangerously high levels for at least a month each year, threatening human health and ways of life.

In warm regions, demand for air conditioning is on the rise. The number of A/C units is estimated to reach 5.6 billionglobally by 2050, up from around 2 billion units today. But populations without the means to obtain and maintain these costly systems will be left out in the cold — or, rather, heat.

Traditional vapor-compressor air conditioners also have considerable environmental costs. They are energy guzzlers, and if fossil fuels are burned to obtain that energy, more planet-warming emissions are released into the air. The toxic refrigerants many of these systems rely on are also potent greenhouse gases that can leak into the atmosphere.

In its current form, A/C is no panacea for beating the climate-change heat. But how else can we keep cool?

The most promising solutions on the horizon leverage technology — some of it cutting-edge, some of it downright ancient.

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