Sunday 10 September 2017 00.05 BST
As the US comes to terms with its second major weather disaster within a month, an important question is whether the devastation caused by hurricanes Harvey and Irma will convince Donald Trump and his administration of the reality of climate change.
The president’s luxurious Mar-a-Lago estate in Florida may escape Irma’s wrath, but with the deaths of so many Americans, and billions of dollars in damage to homes and businesses, the costs of climate change denial are beginning to pile up at the door of the White House.
Just days before Harvey formed in the Atlantic last month, Trump signed an executive order to overturn a policy, introduced by his predecessor Barack Obama, to help American communities and businesses become more resilient against the risks of flooding, which are rising because of climate change.
But the merciless assault on the US mainland by Harvey and Irma should be forcing the president to recognise the consequences of his arrogance and complacency in dismissing the research and analysis carried out by scientists.
The flooded streets of Houston and the wind-ravaged homes of south Florida bear the unmistakable fingerprint of extreme weather made worse by manmade greenhouse gas emissions.
After a period of 12 years when none of the strongest storms made American landfall two major hurricanes have hit the US mainland
A hurricane is a huge, rotating cluster of thunderstorms that forms above a sea surface that has a temperature of at least 26.5C. It is like a giant engine, transferring heat from the sea surface up into the atmosphere and generating strong winds and heavy rain in the process.
The Atlantic hurricane season officially runs from 1 June until 30 November, and typically produces 12 tropical storms, of which six reach hurricane strength – with sustained wind speeds of more than 73mph. There have been 11 storms so far this year, including six hurricanes. In early August, the National Oceanic and Atmospheric Administration raised its prediction for the season to “above normal”, suggesting that the final tally could be up to 19 storms, with nine of them hurricanes.
But this season has already been remarkable in one respect because two major hurricanes, with sustained winds of more than 110mph, have hit the US mainland, after a period of 12 years when none of the strongest storms made American landfall.
Hurricane Irma has also set records for being the strongest hurricane to have occurred in the open Atlantic, and for having sustained wind speeds of at least 185mph over the longest period.
The president should recognise the consequences of his arrogance in dismissing the scientific research
Climate change cannot be blamed for the hurricane count in any single season, nor for the occurrence of any single storm, but there are three ways in which it is making the consequences worse.
Bob Ward is policy and communications director at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics and Political Science