Almost a decade after the financial crisis, economies in just about every corner of the world — the United States, Europe, even perennially sluggish Japan — are growing in unison.

But can the expansion last?

Many economists predict it will — at least into this year. But they also fret that unresolved problems embedded in the global economy, including income inequality and stagnant productivity, could hamper further gains and stall growth once again. As the world’s business leaders gather this week at the World Economic Forum in Davos, Switzerland, confronting these issues will be high on the agenda.

“We will see the momentum created by the recovery continuing into 2018,” said Shanta Devarajan, senior director for development economics at the World Bank. “But the biggest question is how sustainable that is going to be. That is what we are mostly concerned about.”

The World Bank forecasts that global growth this year will reach 3.1 percent, a slight improvement from its estimated 3 percent rate for 2017. That would be the fastest pace since the post-economic-crisis bump in 2011. While the world’s advanced nations are expected to slow marginally, the World Bank projects emerging economies will gain speed, with 4.5 percent growth this year compared with an estimated 4.3 percent in 2017.