FOX Weather hurricane specialist Bryan Norcross breaks down the complex tropical cyclone data used in a recently published study in Nature.
Titled “Seasonal advance of intense tropical cyclones in a warming climate,” the study states that intense tropical cyclones have been occurring earlier than usual in most tropical oceans since the 1980s. Researchers said this phenomenon is largely driven by the warming effects of greenhouse gas forcing.
The study has gained much attention in the weather news space, including some outlets stating that this year’s active hurricane season in the Atlantic is demonstrative of the study’s findings.
However, Norcross analyzed the study and said there are a few aspects to consider.
He notes that first, the study has a global perspective. This means that it includes data about hurricanes, which are tropical cyclones in the Atlantic, along with typhoons and other tropical cyclones of different names around the world. He said that much of what the study covers involved tropical cyclones on the western side of the Pacific Ocean.
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Also, the time period of the data set used ranges from 1981 to 2017, which introduces a couple of complexities. According to Norcross, this period of 36 years includes half of a suppressed hurricane era and about half of an enhanced hurricane era.
“That suppressed area was caused by air pollution coming from Europe, kind of shielding the Atlantic Ocean we know now,” he said. “So, that’s not in the picture now.”
Because of this, the upward trend that seems apparent in the data set from the 1980s appears to be influenced by the exceptionally lower numbers of hurricanes in the Atlantic, as caused by European air pollution.
Whether this year’s active hurricane season in the Atlantic is demonstrative of the global tropical cyclone activity remains to be seen.
Tropical cyclone activity occurs throughout the year around the world, according to the State Department. The Atlantic hurricane season runs from June through November, cyclones in the South Pacific Ocean and Indian Ocean typically occur between November and April and typhoon season in the Northwest Pacific Ocean runs from April through December.