Researchers have projected that climate change will make dangerous temperatures more common during the Arba’een pilgrimage by the end of the 21st century, threatening participants with an increased risk of heat-related illness. Around 20 million Shia Muslims participate in Arba’een, which is one of the world’s largest religious gatherings.
Pilgrims are exposed to the elements while traveling on foot to Karbala, Iraq, where they commemorate the martyrdom of Al-Hussain ibn Ali, the grandson of the Prophet Muhammad. On one popular route, pilgrims travel around 80km from Najaf, Iraq, and typically reach Karbala within one to three days. However, other routes can be as long as 500km.
Arba’een is scheduled according to the Islamic calendar, which is based on the lunar cycles, so it occurs 11 days earlier on the solar calendar each year, progressing through the seasons. Wintertime temperatures during Arba’een should remain tolerable, but when Arba’een occurs in the summer, heat stress is likely to reach dangerous levels by the end of the 21st century, according to a new study.
The study’s authors, Yeon-Woo Choi and Elfatih Eltahir, used regional climate models to predict how future climate change could threaten the health of Arba’een pilgrims. Their models forecasted future wet-bulb temperature, the lowest temperature to which evaporating water can cool air based on the local air temperature and humidity. Wet-bulb temperatures exceeding 24°C become dangerous because sweat cannot sufficiently prevent the body from heating up.
In high greenhouse gas emission scenarios, the study predicts that average summertime temperatures could cross this danger threshold between 2050-2060. The authors say that increasing night-time temperatures may also prove problematic as they prevent pilgrims from adequately recovering from exposure to the day’s heat.
As climate change increases the region’s temperatures, it could put additional strain on healthcare systems already challenged by heat waves. Daytime temperatures during this year’s pilgrimage, which began ahead of the start of Arba’een on September 16, were a challenge. According to news channel Aljazeera, some pilgrims fainted when temperatures reached 41°C. The study suggests that such extreme heat events will become more common if Iraqi summers continue to warm.
To view the complete study published in the AGU journal Geophysical Research Letters, click here.