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Heftier hurricanes, simmering summers, wilder wildfires? Studies point to human-caused climate change

Now here’s a climate change twist: the U.S. weather agency — forecasting lots of Atlantic hurricanes — finds reducing air pollution causes more hurricanes.

Thunderheads spawned by a tropical storm over western Florida sweep across St. Simons Sound in south Georgia
Thunderheads spawned by a tropical storm over western Florida sweep across St. Simons Sound in south Georgia (AN/R. Powers)

WASHINGTON (AN) — Now here’s a climate change twist: America's weather agency — which forecasted a seventh straight abnormally busy Atlantic hurricane season on Tuesday — finds that reducing air pollution results in more hurricanes.

Above-average hurricane activity is expected this year, which would make it the seventh consecutive above-average hurricane season, according to forecasters at the U.S. National Oceanic and Atmospheric Administration’s Climate Prediction Center, a division of the National Weather Service.

They say the 2022 Atlantic hurricane season from June 1 to November 30 will likely have 14 to 21 named storms with winds 63 kph or higher, compared with an average of 14 a year. Six to 10 could become hurricanes, and three to six could be major hurricanes.

“As we reflect on another potentially busy hurricane season, past storms — such as Superstorm Sandy, which devastated the New York metro area 10 years ago — remind us that the impact of one storm can be felt for years,” said NOAA Administrator Rick Spinrad.

A study by NOAA published in May in the journal Science Advances says lower emissions of particulate air pollution in Europe and North America contribute to increasing the number of tropical cyclones in the North Atlantic basin, while decreasing the number of storms in the Southern Hemisphere.

Relying on data collected over 40 years, NOAA also says the increasing air pollution in Asia as the region grows more industrialized has contributed to fewer tropical cyclones in the western North Pacific basin.

As Europe and North America reduced air pollution from industry, cars, trucks and other sources by about half between 1980 and 2020, the absence of this pollution has resulted in surface warming over the tropical Atlantic Ocean, which contributes to more frequent tropical cyclones.

Without significant amounts of particulate pollution to reflect sunlight, the ocean absorbs more heat and warms faster. A warming Atlantic, the report says, has been a key ingredient to a one-third increase in the number of tropical cyclones during the study period.

“Air pollution is a big environmental risk to human health and we have made great strides in reducing health risks by reducing particulate air pollution,” says Hiroyuki Murakami, a scientist at NOAA’s Geophysical Fluid Dynamics Laboratory and author of the new study. “But reducing air pollution does not always decrease the risk of hazards from tropical cyclones.”

Warming of the Atlantic in the northern hemisphere also causes shifts in the jet stream that allow hurricanes to develop and grow. In the North Pacific, NOAA says the processes at work are “the flip side” of what’s happening in the Atlantic.

'Failure to tackle climate disruption'

The key ingredient for the decrease of tropical cyclones in the western North Pacific is also air pollution. Murakami says a 40% increase in the concentration of particulate air pollution has been one of several factors that has contributed to a 14% decrease in tropical cyclones. Other factors include natural variability and increased greenhouse gases.

A warming planet remains one of the most pressing challenges facing humankind and the U.N.’s World Meteorological Organization says the past seven years were the hottest on record. Last year, four key climate indicators broke new records: sea level rise, ocean heat, ocean acidification and greenhouse gas concentrations, WMO said in a new report.

United Nations Secretary-General António Guterres minced no words. He called WMO's findings a “dismal litany of humanity’s failure to tackle climate disruption.”

As weather becomes more unpredictable and violent due to effects of industrialization and climate change, extreme weather events exact a heavy toll. Over the past five decades, WMO said in an earlier report, a weather, climate or water-related disaster has occurred on average every day, at a daily cost of 115 lives and more than US$200 million in damages.

WMO is calling for early warning systems and risk assessments to help ensure that all nations “especially the most vulnerable, are more resilient to the socioeconomic consequences of extreme weather, climate, water and other environmental events.”

In its most recent global survey of air pollution, WMO said the economic downturn associated with the outbreak of the COVID-19 pandemic led to a reduction in some air pollution. However, higher than normal wildfire activity in Australia, Africa, South America, Siberia and the American West resulted in “anomalously high” concentrations of particulate matter in the atmosphere.

WMO found 2020 was an exceptional year in terms of carbon released into the air by wildfires in Siberia and the western United States, especially California. The fires were so massive that extremely dense and expansive smoke plumes were visible from space. The behavior of wildfire in the major burning regions in the Northern Hemisphere can be at least partly attributed to persistent weather patterns in the summer of 2020, for example, a historic heatwave in Siberia.

“These conclusions are concerning because they may reflect a strengthening signal of changing climate on weather-induced mechanisms that alter fire behavior and pollutant emissions on large scales,” WMO says. The prolonged Siberian heatwave of 2020 would have been almost impossible, researchers say, without human influence on the climate.