The Great Lakes keep rising.

Last year the five lakes that together hold 20 percent of the fresh surface water on the planet broke 10 high-water records, and more are expected to fall this year. The inundation follows a 15-year span from 1999 to 2014 when the so-called upper lakes of Superior, Michigan and Huron experienced the longest period of low water in recorded history.

The lakes have always been tempestuous neighbors, but today they appear to be entering a new era of volatility that is testing the region as never before. The simple explanation is that the last five years have been the wettest in history in the Great Lakes watershed, which encompasses parts of eight states and two Canadian provinces. But some scientists believe a more complicated dynamic is at work: a warming climate that will continue to cause extreme fluctuations in weather and water levels, threatening havoc for lakeside homeowners, towns and cities, tourism and shipping.

To guard against rising waters, the city of Chicago has installed flood barriers along the lakefront in various locations. The State of New York has pledged $300 million to raise roadways, upgrade sewers and armor shorelines to help blunt wave action and reduce flooding on the south shore of Lake Ontario. And in Wisconsin this week Gov. Tony Evers asked President Trump to declare three counties to be federally designated disaster areas because of extensive flooding and damage along Lake Michigan. Chicago made a similar request last week.

All of this has many lakefront property owners reconsidering their relationship with the lakes they love. Should people living in areas prone to flooding and shoreline erosion pack up and leave? Or should they stay, and at what cost to themselves and taxpayers? How much are communities willing to spend to protect against storms and rising waters?