Reuters: Zulekhan Mumtaz has seen her livelihood as a seller of camel milk turn sour because of a brutal heat wave that left Pakistan sweltering for three weeks in May with temperatures up to 51 degrees Celsius. “My customers say they can no longer buy spoilt milk and squander their money,’ the 31-year-old said, looking at the clotted yellow liquid. “How can I buy fodder for the camel and food for my two children if the heat wave damages my milk?’ she asked, resting with her animal in the shade of a tree…