A new study is blaming 2017's unusually high number of hurricanes on the Atlantic Ocean's rising surface temperatures. The report is one of the first to suggest that human-driven global warming is actually causing more hurricanes.
The study published in last week's journal Science also predicts that as warming increases over the next 50 to 100 years, about two more hurricanes on average will form annually than we get now. In addition, those hurricanes will be stronger and wetter.
'The new normal'
It's a common refrain in these days to refer to outrageous weather events as "the new normal," but those claims have been hard to quantify. Scientists do know the Earth is getting warmer, and evidence shows humans are contributing to the problem. But scientists have warned against attributing individual weather events to changes in climate, explaining that weather and climate are two different things.
But by any standard, 2017 was a tough year for people living on the Atlantic and Gulf coasts of the United States. Hurricane Harvey turned parts of coastal Texas and the city of Houston into a watery mess. And Hurricane Maria battered Puerto Rico so badly, the island only completed its power restoration projects in August of this year.
Using a new climate model, scientists at the National Oceanic and Atmospheric Administration began studying a particular swath of warming tropical Atlantic water near the equator. Speaking to VOA, author Hiro Murakami says water was especially warm last year and their model predicted about two more major hurricanes than usual. In reality, there were two more than average.
Get used to it, Murakami says. When this area of Atlantic water gets unusually warm, as it did in 2017, the U.S. should expect at least two extra hurricanes a year, he explains, adding that as the planet warms, that area of the Atlantic should heat up more and more often.
"Last year we saw six major hurricanes," he said. "But these six could be eight major hurricanes in the future given the same summer conditions."
That's bad news for people who live near the coast and for the government officials who have to prepare for the massive storms.
Tom Delworth, another NOAA researcher who contributed to the study, says the new model can predict not only what's going to happen this season, but also "100 years in the future." And, he says, "50 to 60 years in advance, later in this century, the most intense storms will become even more intense category 4 and 5. They will be even stronger."
Delworth and Murakami say their model is also applicable to typhoons in the Pacific, and warming waters there should have a similar effect in regions getting battered by those late summer storms.
Both researchers pointed to the unique value of the model in being able to predict hurricanes in the next week, the next month and the next century. However, they admit that while their model can fairly accurately predict what the hurricane seasons will look like in the months and years ahead, it can't predict specific storms.
What good is it to know that more hurricanes are coming if we don't know exactly where and when? Delworth says it can be incredibly empowering for first responders as they prepare for any given hurricane season. "Let's have a lot of emergency supplies on hand," he suggested, as an example, "because we think this is going to happen."
He also says that every year, little by little, modelers and climate scientists are getting better and better at what they do. "That's a very optimistic thing," Delworth said. So, even as hurricanes get stronger and more numerous, forecasters may be able to get ahead of the game, or ahead of the storm, and ultimately save lives.