In the 2000s, former President Hugo Chávez of Venezuela bet his country’s economic future on a rising China, securing tens of billions of dollars in investments and loans-for-oil deals. It paid off at first. China voraciously consumed Venezuelan oil and financed infrastructure projects from a high-speed railway to power plants.

The 2010s brought a reckoning. Oil prices fell, and growth in Chinese oil demand slowed along with its economy. Venezuela’s oil export revenues plummeted, from more than $73 billion in 2011 to $22 billion in 2016. Misrule by Mr. Chavez and his handpicked successor, Nicolás Maduro, and myriad other domestic problems already had Venezuela on the brink; the gamble on China helped push it over the edge. In 2014, Venezuela’s economy collapsed. People scavenged for food in garbage dumps, hospitals were short of essential medicines and crime surged. Since then, nearly eight million people have fled the country. China largely cut Venezuela off from new credit and loans, leaving behind a slew of unfinished projects.

Venezuela’s over-dependence on China was an early warning that the world ignored. Dozens of other countries that rode China’s rise are now at serious risk of financial distress and debt default as the Chinese economy stagnates. Yet China refuses to offer meaningful foreign debt relief and is doubling down at home on its protectionist trade practices when it should be undertaking reforms to free up and restart its economy, the world’s second-largest and a crucial engine of global growth.

This is the flip side of China’s “miracle.” After the 2008 global financial crisis, the world needed an economic savior, and China filled that role. Starting in 2008, it pumped $29 trillion into its economy over nine years — equivalent to about one-third of global G.D.P. — to keep it going. The positive ripple effects were felt worldwide: From 2008 to 2021 China accounted for more than 40 percent of global growth. Developing countries eagerly attached themselves to what seemed like an unstoppable economic juggernaut, and China became the top trading partner for most of the world’s nations. Like Venezuela, many discovered that the booming Chinese economy was a lucrative new market for their commodity exports, and they leaned heavily into that, allowing other sectors of their economies to languish.

China also lent more than $1 trillion abroad, largely for infrastructure projects to be built by Chinese companies under its Belt and Road Initiative. Over the past two decades, one in three infrastructure projects in Africa was built by Chinese entities. The long-term debt risks for fragile developing economies were often ignored.