Poverty has been creeping into the suburbs for the last 20 years, and the rise of online retailers could be making it worse.

According to a new book, "Places in Need: The Changing Geography of Poverty,"by University of Washington professor Scott Allard, American suburbs are facing economic hardship on a massive, if poorly understood, scale.

As of 2014, urban areas in the US had 13 million people living in poverty. Meanwhile, the suburbs had just shy of 17 million.

The Great Recession of 2008 helped accelerate much of the poverty that emerged in the early 2000s, Allard's research has found. But another disrupting factor was the technological shift that enabled — and continues to enable — online retailers like Amazon and other e-commerce sites to replace shopping malls and big-box stores.

This ongoing demise has hollowed out many of the jobs suburban Americans once turned to as a means of supporting themselves.

"When we think about the current labor market, there's reason to be concerned about the disappearance of good-paying, low-skill jobs," Allard told Business Insider.