MAYA GEBEILY AS thousands of devout Muslims flock to Islam's holiest sites in Saudi Arabia for the annual haj pilgrimage this week, scientists warn the sacred rite is under threat due to deadly rising heat. The risk of pilgrims suffering life-threatening heatstroke could rise five-fold with global warming of 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial times, found the study in the journal Environmental Research Letters. With an increase of 2C - the less ambitious goal of the 2015 Paris Agreement - the probability becomes 10 times higher, said Climate Analytics, a Berlin-based think-tank. "The region is already susceptible…