Hotter, longer, more often. Heat waves like the one currently raging across much of Europe or the record-breaking heat spell India and Pakistan suffered in March are a dead giveaway of climate change, experts said on Monday.
– people fault –
“Every heatwave we experience today has become hotter and more frequent because of human-caused climate change,” said Friederike Otto, Senior Lecturer at Imperial College London’s Grantham Institute for Climate Change.
“It’s pure physics, we know how greenhouse gas molecules behave, we know there’s more in the atmosphere, the atmosphere is getting warmer and that means we expect more frequent heat waves and hotter heat waves.”
In recent years, advances in the discipline known as attribution science have enabled climatologists to calculate how much global warming contributes to individual extreme weather events.
The heat wave between India and Pakistan, for example, has been calculated to be 30 times more likely, with more than 1.1 degrees Celsius of warming caused by human activities since the mid-19th century.
The heatwave that broke records in North America in June 2021, leaving hundreds dead in their wake as temperatures soared to 50°C in places, would have been virtually impossible without global warming.
And the last major European heatwave in 2019 was made 3°C hotter by climate change.
“The increase in the frequency, duration and intensity of these events over the past few decades is clearly linked to the observed warming of the planet and can be attributed to human activities,” the World Meteorological Organization said in a statement Monday.
– It gets worse –
No matter how unbearable the temperatures will be this week, the scientists agree: it will get worse.
With warming of 1.5°C – the most ambitious goal of the Paris climate agreement – UN climate scientists calculate that heat waves will be more than four times more likely than on the pre-industrial base.
At 2°C, or warming, that number is 5.6 times more likely, and at 4°C, heat waves will be nearly 10 times more likely.
Despite three decades of UN-led negotiations, countries’ climate plans are currently putting the Earth on track to warm a “catastrophic” 2.7C, according to the UN.
Matthieu Sorel, climatologist at Meteo-France, said climate change is already affecting the frequency and severity of heat waves.
“We are on the way to increasingly hotter summers where 35°C is becoming the norm and 40°C is regularly reached,” he said.
– Risk of death –
The heat waves of the future will largely depend on how quickly the global economy can be decarbonized.
The UN climate science panel has calculated that 14 percent of humanity will be hit by dangerous heat every five years with a warming of 1.5°C, compared with 37 percent with 2°C.
“In every place in the world where we have data, exposure to high temperatures increases the risk of mortality,” said Eunice Lo, a climate scientist at the University of Bristol’s Cabot Institute for the Environment.
It’s not just the most vulnerable people who are at risk of heat-related health effects, but also the fit and healthy who are at risk.”
In the future, there is a real danger that so-called “wet-bulb” temperatures – at which heat combines with moisture to create conditions where the human body cannot cool itself with sweat – will exceed lethal levels in many parts of the world.
In addition to posing an immediate threat to human health, heatwaves are exacerbating droughts and leaving larger areas vulnerable to wildfires like those now raging in parts of France, Portugal, Spain, Greece and Morocco.
They also threaten the food supply.
India, the world’s second-largest wheat producer, has opted to ban grain exports after the heatwave hit harvests and exacerbated a shortage in some countries sparked by Russia’s invasion of key exporter Ukraine.
#fingerprints #climate #change #increasingly #hotter #heat #waves
