Man-made climate change has made UK heat wave 10 times more likely, study finds


LONDON — When Britain experienced its highest temperatures on record, during an extreme heat wave last week, scientists had little doubt the blistering event was supercharged by the uncontrolled release of greenhouse gases of greenhouse by humanity.

Now a group of researchers, using observational data and climate modeling, have sought to calculate how much human-fueled climate change is to blame. The analysis, carried out by the highly respected group World Weather Attribution, concluded that global warming made this UK heat wave “at least 10 times more likely”.

The heat broke records, with the mercury soaring to 40.3 degrees Celsius – or 104.5 degrees Fahrenheit – in Coningsby, England on July 19. Temperatures at Heathrow International Airport and St. James Park in central London were only a fraction of a degree less intense.

UK experiences hottest day on record, with temperatures reaching 40 degrees Celsius

The researchers determined that in a pre-industrial world, around 1850, the same heat wave would have been colder by 4 degrees Celsius (based on observational data) or 2 degrees Celsius (computer modeling suggests).

The World Weather Attribution team specializes in examining the links between current weather events and climate change. He found that climate change made devastating pre-summer heat in India and Pakistan 30 times more likely; worsening heavy rains and deadly floods in South Africa; and increased the power and damage of Japanese Super Typhoon Hagibis.

The same group – which is made up of scientists from around the world – said the early summer heat wave in the Pacific Northwest, which saw temperatures in Portland reach 116 degrees Fahrenheit, would have been “virtually impossible” before climate change.

Britain’s heat wave would have been “extremely unlikely” without human-induced climate change, the researchers said.

Local records were broken at 46 weather stations across the country. The previous record for Britain was 38.7 degrees Celsius (101.6 degrees Fahrenheit) in 2019.

That might not sound very hot for someone summering in Karachi or Houston. But remember: the UK government estimates that less than 5% of UK homes have air conditioning. The country and its infrastructure are not built for these extremes.

Stay cool and carry on? Britons are having the hottest day on record.

“Heat waves are often invisible disasters,” unlike floods or hurricanes, said Emmanuel Raju, from the Center for Disaster Research at the University of Copenhagen and one of the report’s authors.

A full tally of the July heat wave’s lethality will take a month or more as researchers dig into death certificates. But the report warns: “impacts include projections of excess mortality of more than 840 people” for the two-day event, as well as “hospitalizations, infrastructure damage and psychosocial effects”.

In the “natural climate” world, before the deployment of the steam engine in the industrial revolution, the level of atmospheric carbon dioxide was 280 parts per million. Today it’s 412 million parts per million – and the planet is on average 1.2 Celsius warmer.

Most governments around the world have pledged to keep future warming “well below” 2 degrees Celsius while continuing efforts to limit it to 1.5 Celsius.

2C or 1.5C? How global climate goals are set and what they mean

So far, the planet appears to be on track to exceed these targets. According to current trajectories, the world is expected to warm by 2.7 degrees Celsius (4.9 degrees Fahrenheit) by the end of the century.

Analysis of Britain’s heat wave found its probability in a 1.2 Celsius cooler pre-industrial world was “extremely low” – and “statistically impossible” at two of three weather stations in England they looked at.

Friederike Otto, one of the authors of the study, based at Imperial College London, said that due to climate change “each heat wave is more likely and more likely to be more extreme”.

Even so, these are still rare occurrences.

Post Reports podcast: Britain’s hottest day ever

In today’s climate, given current levels of greenhouse gases in the atmosphere, one would expect a repeat of the UK heat wave once every 100 years. For 1-day maximum temperatures above 40 degrees Celsius, the return time is estimated to be 1 in 1000 years.

But that’s for the “current climate,” the researchers warned. Assuming greenhouse gas levels increase over the next few decades, they predict so will the frequency of killer heat.

According to models run by the British Meteorological Office, a 40 degree Celsius day could occur once every 15 years by 2100 if countries meet their carbon emissions pledges – or once every three or four years if they continue to emit as much pollution as they do today. .

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