Climate threatsStudy: Climate Change Could Pose Danger for Muslim Pilgrimage

By David L. Chandler

Published 23 August 2019

For the world’s estimated 1.8 billion Muslims — roughly one-quarter of the world population — making a pilgrimage to Mecca is considered a religious duty that must be performed at least once in a lifetime, if health and finances permit. The ritual, known as the Hajj, includes about five days of activities, of which 20 to 30 hours involve being outside in the open air. , because of climate change there is an increasing risk that in coming years, conditions of heat and humidity in the areas of Saudi Arabia where the Hajj takes place could worsen, to the point that people face “extreme danger” from harmful health effects.

For the world’s estimated 1.8 billion Muslims — roughly one-quarter of the world population — making a pilgrimage to Mecca is considered a religious duty that must be performed at least once in a lifetime, if health and finances permit. The ritual, known as the Hajj, includes about five days of activities, of which 20 to 30 hours involve being outside in the open air.

According to a new study by researchers at MIT and in California, because of climate change there is an increasing risk that in coming years, conditions of heat and humidity in the areas of Saudi Arabia where the Hajj takes place could worsen, to the point that people face “extreme danger” from harmful health effects.

In a paper in the journal Geophysical Review Letters, MIT professor of civil and environmental engineering Elfatih Eltahir and two others report the new findings, which show risks to Hajj participants could already be serious this year and next year, as well as when the Hajj, whose timing varies, again takes place in the hottest summer months, which will be from 2047 to 2052 and from 2079 to 2086. This will happen even if substantial measures are taken to limit the impact of climate change, the study finds, and without those measures, the dangers would be even greater. Planning for countermeasures or restrictions on participation in the pilgrimage may thus be needed.

The timing of the Hajj varies from one year to the next, Eltahir explains, because it is based on the lunar calendar rather than the solar calendar. Each year the Hajj occurs about 11 days earlier, so there are only certain spans of years when it takes place during the hottest summer months. Those are the times that could become dangerous for participants, says Eltahir, who is the Breene M. Kerr Professor at MIT. “When it comes in the summer in Saudi Arabia, conditions become harsh, and a significant fraction of these activities are outdoors,” he says.