Natural disasters in China cause tens of billions of dollars in economic loss and hundreds of deaths every year. While people accept most of the disasters as unpreventable, the losses worsen already stark social inequality.  This summer, Mengwa, a region in the eastern Chinese province of Anhui, became one of the worst-hit areas during China’s record flooding, not because of the abundant rainfall but because it is one of the country’s biggest flood diversion zones. For decades, whenever floods threaten the industrial zones and key transportation hubs downstream, this region becomes submerged when officials release the Wangjia dam upstream.  For the authorities, it makes sense to flood a vast rural area that contributes less to the country’s GDP.

Last month, the dam released 375 million cubic meters of water to Mengwa to ease flooding elsewhere. Dozens of villages were underwater and thousands of hectares of crops were impacted. A popular saying in China encourages people to “make a small sacrifice to achieve a bigger goal,” and local officials in Anhui, proud of their region’s sacrifice, like to say that the people there are the embodiment of this spirit. It’s a big sacrifice: The government compensates the agricultural loss at only 40% to 70% of the previous year’s income. China’s rural population, dependent on agriculture, is poorer than urban residents, and insurance that covers losses from natural disasters is too expensive for most people outside cities.

I recently visited Wanzhou, near the Yangtze River. It’s a town far away from Mengwa, but it also struggles with overwhelming water every summer. Many shop owners told me the damages from a recent flood has cost them years of savings. A single flood has pushed many rural working-class people into poverty overnight. “It only takes one downpour to press me back into a poor street beggar,” said 58-year-old Yang Cheng, whose grocery shop was ruined in a flood last month.

“The less-developed regions will sacrifice for more social-economically-important cities or industrial regions when the floods threaten the latter,” said Ma Jun, director the Institute of Public and Environmental Affairs, “The poor regions are damaged worse from natural disasters and have more difficulties in developing. It becomes a vicious circle.”

This is also a global issue. According to the United Nations Office for Disaster Risk Reduction, research over the past 30 years has shown that poor people are more likely to live in hazard-exposed areas and are less able to invest in risk-reducing measures. Poverty makes you more vulnerable to disaster, and disaster exacerbates poverty.

“Climate change is not only an environmental issue, but also one of equality and justice because the most vulnerable communities bear the most cost of the climate change,” said Li Shuo, a climate analyst for Greenpeace. The floods in southern China this summer have made this point abundantly clear.