August 1, 2024
SINGAPORE – The blistering heatwave that gripped much of the Mediterranean in July and left athletes and fans at the Paris Olympics struggling to cope could not have occurred without climate change due to human activity, a study published on July 31 said.
The analysis by World Weather Attribution (WWA), an international collaboration of scientific institutions, found that global warming caused temperatures to rise by up to 3.3 deg C during the heatwave.
Climate change is primarily driven by greenhouse gas emissions from burning fossil fuels and deforestation. As these emissions accumulate in the atmosphere, they cause the planet to heat up.
“Once impossible, these heatwaves are now relatively common due to human-caused warming and are expected to occur about once a decade. With further warming, they will become even more frequent,” WWA said in a statement.
Greece, Italy, Spain, Portugal, France and Morocco have all experienced extreme heat during July with furnace-like winds blowing in from the Sahara. The heatwave has reportedly killed at least 23 people, but likely many more have died, the researchers said.
It was caused by a large high-pressure ridge, often referred to as a “heat dome”, WWA said. This system began developing over the Mediterranean in the first week of July and persisted and expanded into central and eastern parts of Europe in the following weeks.
The heat dome has since covered Paris, where temperatures hit 37 deg C on July 30, causing fans to seek respite under mist sprayers.
To help athletes cope, tennis and football players were allowed water breaks, BMX riders could sit under umbrellas in between runs, and horses were monitored with thermal cameras.
“Yesterday, climate change crashed the Olympics,” said Dr Friederike Otto, senior lecturer in climate science at the Grantham Institute at Imperial College London, and one of the WWA founders.
“The world watched athletes swelter. If the atmosphere wasn’t overloaded with emissions from burning fossil fuel, Paris would have been about 3 deg C cooler and much safer for sport.”
Dr Otto added: “However, many people across the Mediterranean do not have the luxury of ice packs, air-conditioning or cooling breaks at work. For these people, extreme heat can mean death.”
Mediterranean countries have endured dangerous heat, which widely surpassed 40 deg C in July, reaching 44 deg C in Spain and 43 deg C in Greece.
WWA analyses and communicates the possible influence of climate change on extreme weather events, such as storms, extreme rainfall, heatwaves and droughts, and uses observational data and climate models. The group has completed more than 70 studies on a range of extreme weather events around the world using peer-reviewed methods.
The researchers focused on weather data for this rapid analysis. They said a more detailed attribution analysis including climate models would produce very similar results.
Climate change is making heatwaves hotter, longer and more frequent around the world, and rising heat is one of the clearest manifestations of global warming, WWA said.
The hottest year on record was 2023 and scientists say 2024 is shaping up to be even hotter.
July 21 to 23 were the hottest days on record, according to a Nasa analysis of global daily temperature data. And each of the past 13 months has been the hottest ever recorded.
Heat is a silent killer and one of the deadliest impacts of climate change. The UN World Meteorological Organisation estimates that heat deaths in Europe have increased by about 30 per cent over the past two decades.
A separate study estimated that more than 60,000 people in Europe were killed by extreme heat during the summer of 2022.
“Europe is heating up twice as fast as other continents and even quicker than climate models predict,” said Dr Mariam Zachariah, a researcher at the Grantham Institute.
“Analyses like these help people understand that climate change is not a distant threat, but an immediate one that is already making life on earth much more dangerous.”