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One of the largest disaster relief agencies on Tuesday had a message for the world’s mayors: Heat waves are getting more intense on a hotter planet, but they don’t have to be deadly if city officials take simple and often inexpensive steps.

The International Federation of Red Cross and Red Crescent Societies put out a 96-page guidebook designed to help city officials prepare for heat waves. It repeatedly points out that heat waves are predictable, sometimes days and weeks in advance, and that city officials, and, sometimes private employers, can take steps to save lives.

The tips include what the federation’s president, Francesco Rocca, described as “really simple and affordable” measures. They include knowing when a heat wave is coming; letting people know how dangerous that can be, especially in normally hot places where people might try to shrug off a heat wave; preparing health workers to respond to a health emergencies; setting up cooling centers for those without access to air conditioning; and distributing water.