Climate change caused by humans played a direct role in the deaths of about 1,504 people during a heat wave that struck Europe last week, a new report has found. Warming linked to the combustion of fossil fuels nearly tripled the number of heat-related fatalities that occurred during the June 23 to July 2 period,

Major heat waves across southern Europe have pushed temperatures above 104 degrees Fahrenheit (40 degrees Celsius) in countries including Italy, Spain and Greece, as local authorities issued fresh warnings against the risk of wildfires.

The heat was so expansive that mountaintops, including the French Alps, that are usually frozen from snowpack saw record temperatures. Heat records were set for June in Spain and Portugal.

As millions across Europe endure a blistering heat wave, with record temperatures triggering emergency alerts from Spain to the UK, experts are sounding the alarm over what they describe as a silent and increasingly deadly global crisis.