The poorest third of US counties could lose up to a fifth of their economic output if no action is taken by the end of the century, this article notes, delving into the findings of our 2017 study on climate change and inequality. The impact will be felt most acutely by states in the south and lower midwest, which are already on average poorer and hotter than elsewhere in the US, and cannot expect any benefits from rising temperatures. By contrast, as optimal conditions for crop-growing move further away from the equator, cooler — and wealthier — regions in the northern US could see boosted agricultural output and knock-on improvements to healthcare and energy costs.