Major hurricanes, wildfires, drought and tornadoes have led to highest ever damage costs, as expert says extremes have ‘climate change fingerprints on them’

This article is more than 2 years old

This article is more than 2 years old

With three strong hurricanes, wildfires, hail, flooding, tornadoes and drought, the United States tallied a record high bill last year for weather disasters: $306bn, according to a new government report released on Monday.

The US had 16 disasters last year with damage exceeding a billion dollars, the National Oceanic and Atmospheric Administration (Noaa) said. That ties 2011 for the number of billion-dollar disasters, but the total cost blew past the previous record of $215bn in 2005.



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Costs are adjusted for inflation and Noaa keeps track of billion-dollar weather disasters going back to 1980.

Three of the five most expensive hurricanes in US history hit last year.

Hurricane Harvey cost $125bn, second only to 2005’s Katrina, while Maria cost $90bn, ranking third, Noaa said. Irma was $50bn, for the fifth most expensive hurricane. Western wildfires fanned by heat racked up $18bn in damage, triple the previous US wildfire record, according to Noaa.

Quick guide Tropical storm Harvey and climate change Show Hide Is there a link between the storm and climate change? Almost certainly, according to a statement issued by the World Meteorological Organization on Tuesday. “Climate change means that when we do have an event like Harvey, the rainfall amounts are likely to be higher than they would have been otherwise,” the UN organisation’s spokeswoman Clare Nullis told a conference. Nobody is arguing that climate change caused the storm, but it is likely to have made it much worse. How did it make it worse? Warmer seas evaporate more quickly. Warmer air holds more water vapour. So, as temperatures rise around the world, the skies store more moisture and dump it more intensely. The US National Weather Service has had to introduce a new colour on its graphs to deal with the volume of precipitation. Harvey surpassed the previous US record for rainfall from a tropical system, as 49.2 inches was recorded at Mary’s Creek at Winding Road in Southeast Houston, at 9.20am on Tuesday. Is this speculation or science? There is a proven link – known as the Clausius-Clapeyron equation – that shows that for every half a degree celsius in warming, there is about a 3% increase in atmospheric moisture content. This was a factor in Texas. The surface temperature in the Gulf of Mexico is currently more than half a degree celsius higher than the recent late summer average, which is in turn more than half a degree higher than 30 years ago, according to Michael Mannof Penn State University. As a result there was more potential for a deluge. Are there other links between Harvey and climate change? Yes, the storm surge was greater because sea levels have risen 20cm as a result of more than 100 years of human-related global warming. This has melted glaciers and thermally expanded the volume of seawater.



“While we have to be careful about kneejerk cause-effect discussions, the National Academy of Science and recent peer-reviewed literature continue to show that some of today’s extremes have climate change fingerprints on them,” said University of Georgia meteorology professor Marshall Shepherd, a past president of the American Meteorological Society.

Facebook Twitter Pinterest Firefighters in Santa Barbara County work their way through hillsides left charred by California’s largest-ever wildfire. Photograph: Mike Eliason/AP

At least 362 people died in 2017 due to these natural disasters, the agency reported, including 64 killed in Puerto Rico. Outlets such as the New York Times and BuzzFeed have questioned the official death toll from the island, and estimated that Hurricane Maria has caused the deaths of about 1,000 people.

Noaa announced its figures at the society’s annual conference in Austin, Texas.

The weather agency also said that 2017 was the third hottest year in US records for the lower 48 states with an annual temperature of 54.6F (12.6C), 2.6 degrees warmer than the 20th-century average. Only 2012 and 2016 were warmer. The five warmest years for the lower 48 states have all happened since 2006.

This was the third straight year that all 50 states had above-average temperatures for the year.

Five states Arizona, Georgia, North Carolina, South Carolina and New Mexico had their warmest year ever. Temperature records go back to 1895.