A recent study in Nature Climate Change suggests that climate change will warm the world’s cities by 8 degrees Celsius (14 Fahrenheit). This warming, a combination of the effects of greenhouse gas emissions and local urban heating issues, will have extreme influence on cities’ economies. As cities warm, people lose the ability to work effectively, and, as a city’s workforce dwindles, economic production falters as well, the report warns.

According to the study, the average city could lose about 1.5% of its GDP by mid-century, and lose as much as 5.6% by 2100. The worst-off city could lose as much as 11% of its GDP. Considering that cities produce approximately 80% of the world’s GDP, this loss would prove incredibly damaging.

Image: The cityscape of Kuala Lumpur, capital of Malaysia