“A green card is a feeling of safety,” the manager said. “The system here isn’t stable and you don’t know what’s going to happen next. I want to see how things turn out here over the next few years.”

Political turmoil has reinforced this feeling. Since early this year, the country has been shocked by revelations that Bo Xilai, one of the Communist Party’s most senior leaders, ran a fief that by official accounts engaged in murder, torture and corruption.

“There continues to be a lot of uncertainty and risk, even at the highest level — even at the Bo Xilai level,” said Liang Zai, a migration expert at the University at Albany. “People wonder what’s going to happen two, three years down the road.”

The sense of uncertainty affects poorer Chinese, too. According to the Chinese Ministry of Commerce, 800,000 Chinese were working abroad at the end of last year, versus 60,000 in 1990. Many are in small-scale businesses — taxi driving, fishing or farming — and worried that their class has missed out on China’s 30-year boom. Even though hundreds of millions of Chinese have been lifted from poverty during this period, the rich-poor gap in China is among the world’s widest and the economy is increasingly dominated by large corporations, many of them state-run.

“It’s driven by a fear of losing out in China,” said Biao Xiang, a demographer at Oxford University. “Going abroad has become a kind of gambling that may bring you some opportunities.”

Zhang Ling, the owner of a restaurant in the coastal city of Wenzhou, is one such worrier. His extended family of farmers and tradesmen pooled its money to send his son to high school in Vancouver, Canada. The family hopes he will get into a Canadian university and one day gain permanent residency, perhaps allowing them all to move overseas. “It’s like a chair with different legs,” Mr. Zhang said. “We want one leg in Canada just in case a leg breaks here.”