Leaders of Europe’s biggest oil and gas companies said political leaders attending U.N. climate talks that start this week must make carbon markets more effective and that only governments can effectively curb fossil fuel demand. Oil majors will be among the big companies conspicuous by their absence at the COP26 meeting that begins in Glasgow, Scotland, on Sunday to attempt to agree ways to limit the planet’s warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels. Ben van Beurden, the chief executive of the world’s biggest fuel retailer Royal Dutch Shell (RDSa.L) , told reporters this week that, as oil and gas companies, “we were told that we were not welcome” […]