He once dismissed it as a “hoax” created by the Chinese to destroy American jobs, but right now Donald Trump is pining for some of that “good old global warming”.
While on holiday in Florida on Thursday, the US president wondered whether global warming might not be such a problem after all.
As severe cold and record amounts of snow sweep across the US east coast, Trump wrote on Twitter that the country “could use a little bit of that good old Global Warming that our Country, but not other countries, was going to pay TRILLIONS OF DOLLARS to protect against”.
“Bundle up!” he added.
In doing so, he reheated two of his favourite tropes: the conflation of weather with climate to pour scepticism on global warming, and the supposed cost to the US taxpayer of the Paris climate accord from which he confirmed the US would withdraw in June this year.
Both are well-worn themes of the president’s online repertoire. As far back as 2012 he tweeted: “It’s freezing and snowing in New York – we need global warming.”
But climate scientists have long warned against using individual weather events to ponder the existence or otherwise of global warming because weather refers to the atmospheric conditions during a short period while climate relates to longer term weather patterns.
Matthew England, a climate scientist from the University of New South Wales, labelled Trump’s comment “an ignorant misconception of the way the Earth’s climate works”.
“Nobody ever said winter would go away under global warming, but winter has become much milder and the record cold days are being far outnumbered by record warm days and heat extremes,” he said. “Climate change is not overturned by a few unusually cold days in the US.”
Or, as David Karoly, a climate scientist from the University of Melbourne said: “It’s winter in the US. Cold temperatures are common in winter”.
However, Karoly said climate modelling showed cold snaps like the one being felt on the east coast of the US were actually becoming less common as a result of global warming.
While it’s unwise to draw conclusions form individual events, Karoly said that rapid attribution analysis of climate events meant scientists were now able to look more closely at “classes of events”.
He said that type of modelling for the north east of the US showed that while there was a great deal of year-to-year variability, the average coldest temperature in December in that region had increased in the past 50 years.
In any case, the US is already getting a bit of that good old global warming. 2017 is set to be the country’s third warmest on record, prompting, among other things, a climate-fuelled hurricane season in the country’s south.
The tweet also revisited Trump’s claim that the Paris climate accord would have cost the US economy “trillions” of dollars. At a rally in Pennsylvania in April to mark his 100th day in office, Trump said “full compliance with the agreement could ultimately shrink America’s GDP by $2.5tn over a 10-year period”.
When he made the statement in April the politically non-aligned website Factcheck.org asked the White House for a source, and was pointed to a 2016 study by the conservative Heritage foundation which found the Paris agreement “will result in over $2.5tn in lost GDP by 2035”.
While that’s an 18-year period, not 10, Factcheck.org found the accuracy of Heritage’s statements depended on which numbers were used.
The Heritage study used a carbon tax rate of $36, increasing 3% each year from 2015 to 2035. But other analyses have found that the US would have needed only a carbon tax of $21.22 starting in 2017 to meet its Paris target by 2025.
When he pulled out of the Paris accord, Trump also said the US would stop contributing to the Green Climate Fund, a United Nations program that since 2013 has seen industrialised countries voluntarily pledge $10.3bn to help poorer nations reduce greenhouse gas emissions and address the effects of climate change.