China’s breakneck growth over the last four decades erected soaring cities where there had been hamlets and farmland. The cities lured factories, and the factories lured workers. The boom lifted hundreds of millions of people out of the poverty and rural hardship they once faced.

       Now those cities face the daunting new challenge of adapting to extreme weather caused by climate change, a possibility that few gave much thought to when the country began its extraordinary economic transformation. China’s pell-mell, brisk urbanization has in some ways made the challenge harder to face.

       No one weather event can be directly linked to climate change, but the storm that flooded Zhengzhou and other cities in central China last week, killing at least 69 as of Monday, reflects a global trend that has seen deadly flooding recently in Germany and Belgium, and extreme heat and wildfires in Siberia. The flooding in China also highlights the environmental vulnerabilities that accompanied the country’s economic boom and could yet undermine it.

       China has already taken some steps to begin to address climate change. Xi Jinping is the country’s first leader to make the issue a national priority.

       As early as 2013, Mr. Xi promised to build an “ecological civilization” in China. “We must maintain harmony between man and nature and pursue sustainable development,” he said in a speech in Geneva in 2013.

       The country has nearly quintupled the acreage of green space in its cities over the past two decades. It introduced a pilot program to create “sponge cities,” including Zhengzhou, that better absorb rainfall. Last year, Mr. Xi pledged to speed up reductions in emissions and reach carbon neutrality by 2060. It was a tectonic shift in policy and may prove to be one in practice, as well.

       The question is whether it is too late. Even if countries like China and the United States rapidly cut greenhouse gases, the warming from those already emitted is likely to have long-lasting consequences.