Donald Trump has rejected a central conclusion of a dire report on the economic costs of climate change released by his own administration.
The National Climate Assessment, quietly unveiled on Friday, warned that natural disasters are worsening in the US because of global warming.
It said warming-charged extremes “have already become more frequent, intense, widespread or of long duration”.
The report noted the last few years have smashed US records for damaging weather, costing nearly 400 billion dollars (£312 billion) since 2015.
Mr Trump responded, saying: “I don’t believe it.”
The president, administration officials and elected Republicans frequently say they cannot tell how much of climate change is caused by humans and how much is natural.