Climate change made Hurricane Harvey’s deadly rains and flooding three times more likely, new research has found.
Harvey’s catastrophic downpour, which lashed Houston in August, was made 15 per cent more intense by global warming, the study found.
The storm left 80 people dead and 800,000 either homeless or in need of help, and caused an estimated $200 billion (£150 billion) in damages.
The research shows climate change is already making extreme weather events worse in the US, scientists said.
Climate change made Hurricane Harvey’s (pictured) deadly rains and flooding three times more likely, new research has found. Harvey’s catastrophic downpour, which lashed Houston in August, was made 15 per cent more intense by global warming, the study found
While scientists say man-made climate change didn’t trigger Harvey, two studies show that a warmer, wetter world tripled the likelihood that the hurricane would douse and flood Houston.
Other studies also find climate change factored into the storm’s record rainfall.
The findings, from the World Weather Attribution, were presented today at the American Geophysical Union meeting in New Orleans.
As Harvey battered Texas, researchers suspected that the storm was made worse by global warming, but didn’t have the data to back that up until now.
With an estimated $200 billion (£150 billion) in damages, Harvey is the most costly weather disaster in US history, more than Hurricanes Sandy and Catrina combined.
A number of new studies have linked global warming to an increased likelihood in extreme heatwaves, droughts, floods, storms and wildfires across the globe.
Another new report published today by the American Meteorological Society studied 21 extreme weather events in 2016.
The disasters included South African drought, US snowstorms and Arctic heating.
Hurricane Harvey left 80 people dead and 800,000 either homeless or in need of help, and caused an estimated $200 billion (£150 billion) in damages. New research shows that the storm’s heavy rains and floods (pictured) were made worse by man-made climate change
Most of the devastating events can be at least partly attributed to climate change, the scientists concluded.
Hurricane Harvey first hit US shores on August 25 before hovering over Texas, causing torrential downpours and flooding.
In Houston, a year’s worth of rain was dumped on the city in just a few days.
WWA researchers used climate models and historical rainfall records to study how global warming influenced the hurricane.
While scientists say man-made climate change didn’t trigger Harvey, two studies show that a warmer, wetter world tripled the likelihood that the hurricane would douse and flood Houston. Pictured are Houston residents wading through floods following the storm
As Harvey battered Texas, researchers suspected that the storm was made worse by global warming, but didn’t have the data to back that up until now. Pictured is a truck struggles through floodwaters in Corpus Christi in August
‘This multi-method analysis confirms that heavy rainfall events are increasing substantially across the Gulf Coast region because of human interference with our climate system,’ said study lead author Dr Geert Jan van Oldenborgh, at the Royal Netherlands Meteorological Institute (KNMI).
‘It was very a rare event – they were very unlucky.’
The team found that the chances of Harvey’s deadly downpours were tripled by global warming.
The researchers said their work shows climate change is making extreme weather events worse in the US. Pictured is the aftermath of Hurricane Harvey after it hit Houston
They estimate that the likelihood of such extreme downpours is set to triple again in future, even if the world meets the Paris Climate Accords target to keep global temperatures no more than 2°C (3.6°F) above pre-industrial levels.
‘But, if we miss those targets, the increase in frequency and intensity could be much higher,’ said Karin van der Wiel, also at KNMI.
Dr Friederike Otto, from Oxford University, said: ‘We’re now finding that for many kinds of extreme weather event, especially heatwaves and extreme rainfall, we can be quite confident about the effect of climate change.
‘The ECIU report shows just how quickly knowledge is accumulating, and I think it’s only going to accelerate.’
Dr Dann Mitchell, Lecturer in Climate Physics at Bristol University, said: ‘The recent study suggests that the extreme rainfall component of Hurricane Harvey was made 15 per cent more intense due to climate change, which is broadly in agreement with the atmospheric theory that has been developed in this area.
‘Attribution of hurricane characteristics to climate change is extremely challenging, and the authors have focused only on the precipitation response, which is perhaps the most well understood, and is particularly important given the nature of the flooding in Texas due to Harvey.
‘The purpose of the authors’ work is to provide fast attribution statements on specific events, which they have done.
‘Future extensive research on the validation and understanding of tropical cyclones in their models, rather than only the precipitation statistics, will help to give more confidence in their results.
‘Such research is needed for understanding future changes in cyclones and avoided impacts if we follow the Paris Agreement on climate change, rather than current, high greenhouse gas emission pathways.’