(Bloomberg) -- Just days before devastating floods hit the central Chinese city of Zhengzhou, its province of Henan endured heatwaves that swept across several industrial regions, threatening power outages.

Now the city of more than 10 million is reeling from a record rainstorm that brought a year’s worth of precipitation in three days. The death toll in Henan has climbed to at least 25 and more than 100,000 people were evacuated. Dramatic videos of passengers standing in chest-high water waiting to be rescued from subway cabins, cars swept away as floodwater poured through downtown streets, and children trapped in mud started circulating on social media late Tuesday night.

In a briefing on Wednesday, scientists at the China Meteorological Administration attributed the storm to strong and sustained subtropical high-pressure systems that, along with Typhoon In-fa approaching South China, pushed water vapor from the sea to Henan. When that dense air hit the mountains surrounding the region, it converged and shot upwards, causing concentrated rainfall.

The rains paralyzed the world’s biggest manufacturing base for iPhones and a major hub for food production and heavy industry, days after a heatwave pushed power consumption to record levels, prompting Henan to ban the export of its coal to other regions.

READ MORE: Deadly Floods Sweep China’s Hub for iPhones, Cars and Hogs

“It takes time and research to make a conclusion about the links between all these extreme weather events and climate change,” said Ma Jun, director at the Institute of Public & Environmental Affairs in Beijing. But China has seen more days with extreme rains since the 1960s, he said, and cities “have to be prepared to face similar disasters.”

The Zhengzhou meteorological department issued alerts about the floods, but other government departments didn’t follow through with enough action, Ma said, adding that China needs to better prepare for such catastrophic events by improving weather monitoring and its ability to convey warnings and information quickly.

Chinese meteorologists warned earlier this month that the world’s second-largest economy would suffer more extreme weather events than usual this summer including floods and drought. Climate change is set to bring even more dangerous weather all over the world. In the last few weeks, the U.S. and Canada have experienced unprecedented heatwaves, Europe and India have suffered major floods, wildfires have spread across Siberia and drought has gripped parts of Africa and Brazil.

“The deadly flood shows the unpredictable impacts from climate change are appearing more and more often,” said Zhang Jianyu, chief representative at the Environmental Defense Fund’s Beijing office. “It’s a message to us that it’s time to strengthen efforts to tackle climate change crisis.”

As the world’s biggest emitter of planet-warming greenhouse gases, China can arguably do more than any other country to slow global warming. President Xi Jinping has pledged to reach net zero emissions by 2060, an ambitious goal that will require trillions of dollars and a complete overhaul of the coal-dependent economy.

The tragic scenes from Zhengzhou underscore how important it is for China to deliver on that promise. The city saw 458 millimeters (18 inches) of rain fall in the 24 hours through 5 p.m. on Tuesday, the highest since records began, state media Xinhua reported. Heavy rains will last until Thursday night and strong precipitation will continue in some parts of Henan and neighboring Hebei province near Beijing at about 250 to 280 millimeters per day, according to the China Meteorogical Administration.

While discussing the storm this week, some Chinese meteorologists recalled the last time Henan suffered similar devastation. Officials rarely speak of the earlier floods, which happened in August 1975 during the Cultural Revolution — Chinese refer to the incident as the “758 Extremely Heavy Rain.” That summer, rain triggered by a typhoon caused the collapse of 62 dams and destroyed almost 7 million houses. It was one of the deadliest natural disasters in China’s modern history, with an estimated toll of 26,000 to 240,000.

Chinese authorities avoided talking about the details until the 1990s, partly because the dam failures coincided with an increase in political backlash from the public. Most of the structures that collapsed were built with the help of experts from the Soviet Union and prioritized the goal of retaining water over flood prevention, according to a report published by an official newspaper in 2012.

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