It is time for the Muslim community to become the leaders in the fight, with not just countries such as Bangladesh and Pakistan under threat now, but increasingly the holy site of Mecca.
British Muslims are being urged to take action on climate change, as a study suggests that rising temperatures will make pilgrimages to Mecca hazardous to human health.
Aid agency Islamic Relief UK is urging the Muslim community in the UK to become leaders in the fight to curb dangerous global warming, and put pressure on politicians to cut the country's greenhouse gas emissions.
The call comes as a new study by researchers at the Massachusetts Institute of Technology (MIT) and in California warned that global warming poses an increasing risk to people's health while they are on pilgrimage to Mecca.
The Hajj, one of the five pillars of Muslim faith, takes place outdoors in and surrounding Mecca in the Saudi Arabian desert, and all Muslims are expected to take part at least once in their life, if their health and finances allow.
The annual religious event, whose timings shift each year because it is based on the lunar calendar, involves spending around 20 to 30 hours outdoors over a period of five days.
In a study published in the journal Geophysical Review Letters, researchers warn that rising global temperatures could push up heat and humidity in the region to the extent that people face "extreme danger" from harmful health effects when the Hajj takes place in the hottest summer months.
Risks could already be serious this year and next year, and worsening over the century when the Hajj takes place again in the hottest summer months from 2047 to 2052 and from 2079 to 2086, the researchers warn.
Thresholds where heat and humidity pose a danger to human health are likely to be exceeded with or without action to curb global warming, but the situation will be more severe if nothing is done, they said.
Elfatih Eltahir, the civil and environmental engineer who led the research, said: "When the Hajj happens in summer, you can imagine, with climate change and increasing heat-stress levels, conditions could be unfavourable for outdoor activity.
"Hajj is the largest gathering of Muslims in the world. We are trying to bring in the perspective of what climate change could do to such large-scale outdoor activity."
Tufail Hussain, director of Islamic Relief UK, said the research showed it was "now or never" to take up the fight against climate change, which is already one of the greatest threats to the people the aid agency supports.
"With the threat of catastrophic global heating becoming more evident each year, Islamic Relief UK is calling on the British Muslim community to take action before it is too late.
"It is time for the Muslim community to become the leaders in the fight, with not just countries such as Bangladesh and Pakistan under threat now, but increasingly the holy site of Mecca.
"If we don't act now, not only will people suffer the impact of more frequent and intense disasters, but our children born from today will no longer be able to perform the sacred duty of Hajj."
The charity is encouraging people to call on their MPs to urge immediate moves by the government to bring in policies to reduce climate change, and push for action for the UK to reach "net zero" emissions by 2045 or before.
Emily Beament is the PA environment correspondent.