The catastrophic 2017 hurricane season – which included such monsters as Harvey, Irma and Maria – was fueled in part by unusually warm ocean water, a new study suggests.

And because of human-caused global warming, the study said similar favorable conditions for fierce hurricanes will be present in the years and decades to come.

"We will see more active hurricane seasons like 2017 in the future," said lead author Hiro Murakami, climate scientist and hurricane expert at the National Oceanic and Atmospheric Administration.

Last year, six major hurricanes formed, twice the recent average. By 2100, that average could soar to five to eight major hurricanes a year, according to the study published Thursday in the journal Science.

Sea water in the main hurricane development region of the Atlantic Ocean averaged 0.7 degrees warmer than normal for the entire 2017 season, which is unusual for a full six-month time period, Murakami said.

"We show that the increase in 2017 major hurricanes was not primarily caused by La Niña conditions in the Pacific Ocean, but mainly by pronounced warm sea surface conditions in the tropical North Atlantic," the study said.

La Nina, a periodic natural cooling of the tropical Pacific Ocean, tends to increase hurricane activity in the Atlantic.

The key factor controlling Atlantic major hurricane activity appears to be how much the tropical Atlantic warms relative to the rest of the global ocean, according to the study.

The researchers used computer simulations to pinpoint different climate conditions and also used the computer models to make predictions about the future.

Brian McNoldy, a University of Miami hurricane expert not involved in the study, said it makes sense that the unusually warm ocean water was to blame in 2017. But he wasn't quite ready to blame global warming.

"Hurricane seasons don't just keep getting more active as the climate warms, though. There is enormous variability," McNoldy said.

The three big hurricanes in 2017 caused an estimated $265 billion in damages during a year that shattered all records for U.S. economic losses due to extreme weather, NOAA said.

Contributing: The Associated Press