This summer’s heat waves may have already resulted in more than 2,700 deaths in England and Wales.

That’s according to an estimate published on Monday by researchers at Imperial College London, the UK Met Office and the London School of Hygiene and Tropical Medicine. Climate change pushed temperatures between 3 C and 4 C higher than they would otherwise have been, an effect that taken in isolation is responsible for more than 40 percent of the deaths recorded, the researchers said.

“Heat waves are the most dangerous kind of extreme weather,” said Clair Barnes, a research associate in extreme weather and climate change at Imperial College London. “This extreme heat that we are now exposed to because of human-caused climate change is extremely dangerous to human health.”

The researchers combined historical data on the link between heat and mortality with temperature data to estimate the number of deaths during the latest heat waves. They then modeled how many deaths would have occurred in a cooler world without human-caused warming, noting that the approach has previously produced estimates comparable to those of the UK Health Security Agency for past heat events.

The UKHSA is due to publish an official interim analysis of heat associated mortality impacts of the latest heat waves in the coming weeks, based on observed data.

ALSO READ: Western Europe records hottest June, says EU climate monitor

This year’s record-breaking heat in central and western Europe has already caused close to 10,000 deaths across the UK, France, Spain and Germany, according to research groups and government bodies in the affected countries.

Dangerously high temperatures have also hit earlier than usual. In the UK, a national record for May was set when the temperature reached 35.1 C at Kew Gardens in southwest London. The unprecedented pre-summer heat resulted in an estimated 550 deaths, according to the authors of the study.

In June, three consecutive days of record-breaking temperatures for that month culminated in readings above 37 C in East Anglia, which led to a further estimated 2,200 deaths.

Europe is now already facing its third heat wave of the season. The World Health Organization has warned that the extreme temperatures gripping the region are a “dress rehearsal” for what’s to come, as temperatures continue to rise.

READ MORE: WHO: Over 1,300 excess deaths linked to Europe heatwave

“This combination of extreme daytime heat, high humidity, hot nights all act to really contribute and increase the impact that these heat waves have on our infrastructure, on transport, agriculture, and particularly our health and well-being,” said Mark McCarthy, climate attribution manager at the Met Office. “We are seeing what historically were once rare occurrences happening much more frequently.”