As the Atlantic hurricane season begins June 1 and runs through November, at least one major forecasting body predicts an above-normal season. Still, 2021 is not expected to match the historic wrath of 2020 storms.
Forecasters at the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center see a 60% chance of an above-normal season. Last year produced a record 30 named storms. In fact, there were so many that the list of 21 conventional names was exhausted and the Greek alphabet was used for only the second time ever.
So, what do we know about how climate change has contributed to the history-making devastation?
It’s too simplistic, even lazy, to say for sure that climate change has brought more hurricanes, say scientists.
But we do know that warming sea surface temperatures due to climate change add fuel to hurricanes, making for stronger storms that can strengthen much more quickly, according to Climate Central, which has brought together scientists and journalists to report their findings. The record-breaking 2020 hurricane season included 10 rapidly intensifying storms, meaning their maximum wind speed increased at least 35 mph within 24 hours.
Climate change can also lead to worse flooding accompanying hurricanes. A warmer atmosphere holds more moisture, increasing the amount of rainfall during a tropical storm. Studies project a 10%-15% average increase in rainfall rates of tropical cyclones in a 2°C global warming scenario.
And finally, sea level rise also contributes to higher and more dangerous coastal storm surges. That’s worrisome news for the desirable and densely populated coasts, popular especially among retirees.
One challenge is that the tools that make hurricane forecasts better, like more consistent aircraft reconnaissance and geostationary satellites, also means that we now see storms that we might have missed in the past. Comparisons are difficult.
Experts at the World Meteorological Organization (WMO) and the National Hurricane Center are considering advancing the start date of hurricane season to May 15.
But it’s not yet clear that climate change is causing tropical systems to occur earlier and so the experts are waiting on redefining the June-November hurricane season.
What is clearer is that climate-linked devastation is increasingly costly both in human toll and the financial injury. A record-breaking 22 weather and climate disasters costing over $1 billion each were recorded in 2020, a report from NOAA showed. The tally, which includes everything from hurricanes to wildfires, shattered the annual record of 16 costly disasters in both 2011 and 2017.
Annual losses in 2020 exceeded $95 billion, the fourth highest cost on record, NOAA said. The most costly events of the year included: Hurricane Laura, the Western wildfires and the Midwest derecho.