The world’s largest cities are set to see unprecedented climate-related challenges — such as month-long heat waves, skyrocketing energy demand for air conditioning and a shifting risk for insect-borne diseases — as the planet’s temperature continues to rise, according to analysis by the World Resources Institute.

The WRI compared the sizable effects on cities of 1.5 degrees C (2.7 degrees F) versus 3 degrees C (5.4 degrees F) global warming, which is expected by 2100 without significant action to reduce greenhouse gas emissions. The findings hold immense consequences for people’s lives and livelihoods, as well as for cities’ economies, infrastructure and public health systems.

“The implications are especially important as cities are home to 4.4 billion people globally — more than half the world’s population — and will grow rapidly over the next two decades. By 2050, as another 2.5 billion people move to urban areas, two-thirds of humanity will live