A team of European scientists has attributed the deadly heatwave during the recent Saudi Hajj pilgrimage to the exacerbating effects of climate change.

Temperatures soared to 47 degrees Celsius (117 degrees Fahrenheit) along the pilgrimage route from June 16 to 18, peaking above 51.8°C at Mecca’s Grand Mosque. According to ClimaMeter's weather attribution analysis, human-caused climate change amplified the heat by approximately 2.5°C (4.5°F).

ClimaMeter, specializing in rapid assessments of climate impacts on weather events, used satellite data spanning the past four decades to compare weather patterns from 1979-2001 to 2001-2023.

While the region is no stranger to high temperatures, the scientists noted that natural variability alone couldn't account for the severity of this month’s heatwave, underscoring the role of climate change in intensifying such events.

The assessment also highlighted a shift, noting that historically similar heat events in Saudi Arabia occurred in May and July, whereas now June experiences more severe heatwaves.

Davide Faranda from France’s National Centre for Scientific Research, involved in the ClimaMeter analysis, emphasized the direct link between fossil fuel emissions and the extreme heat impacting vulnerable pilgrims during this year’s Hajj.

Climate change trends indicate that heatwaves are becoming hotter, more frequent, and longer-lasting globally. Previous studies by the World Weather Attribution group suggest that, on average, heatwaves are now 1.2°C (2.2°F) hotter than in preindustrial times.

While medical authorities typically attribute deaths to heat-related illnesses rather than direct heat, experts believe extreme temperatures likely contributed to many of the 1,300 deaths during this year’s Hajj.