By Yadarisa Shabong and Pushkala Aripaka (Reuters) -Shell has turned to the head of its gas and renewables business to drive its transition to a lower-carbon future, picking Wael Sawan to replace Ben van Beurden as chief executive. Sawan’s appointment comes at a pivotal time for the oil giant, which is aiming to reduce emissions to net zero by 2050 and moving away from fossil fuels even as Europe looks to fossil fuels to survive a growing energy crisis. Lebanese-Canadian Sawan, 48, was seen as the front-runner to replace van Beurden, who is stepping down at the end of the year after nearly a d…