The news on the climate front isn’t getting any better. Scientists reported on Wednesday that the influence of climate change on Hurricane Harvey last summer was worse than first thought, with human-caused warming making record rainfall across the Houston area three times more likely than it otherwise would have been.
“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 Geert Jan van Oldenborgh, at the Royal Netherlands Meteorological Institute (KNMI) and lead author of the new study published in Environmental Research Letters.
“It was very a rare event – they were very unlucky,” said van Oldenborgh.
Harvey made landfall on Aug. 25, and then stalled over Texas. The torrential downpours dumped a year’s worth of rain over the area in just six days, with as much as 52 inches falling in east Harris County, the highest storm total on record. The storm left 80 people dead and caused an estimated $190 billion in damage.
The new assessment was made by scientists from the World Weather Attribution (WWA) initiative. They used historical rainfall records and high-resolution climate models to determine warming’s impact on the storm and found that Harvey’s rain totals were 15 percent higher than would be expected without climate change.
Ominously, the researchers said that even if the world meets its target of limiting overall warming to 2° C, the odds of such extreme downpours would likely triple again. The picture is significantly worse if those targets are missed.
A second study released Wednesday by the American Meteorological Society found that human-caused climate change played at least some role in almost all of the 21 different extreme weather events the researchers studied in 2016. That bolsters new findings released by the United Kingdom’s Energy and Climate Intelligence Unit (ECIU), which examined 59 studies published in the past two years and found warming made extreme weather events worse in 70 percent of cases.
“The link between global warming and more extreme weather is nowhere more obvious than in the US. Even if Donald Trump isn’t seeing the picture, many others are,” said Richard Black at the ECIU.
Friederike Otto, at 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.”