Leaders of the Group of 20 major economies began arriving on Monday at Rio de Janeiro's Modern Art Museum for their annual summit, bracing for a shift in the global order with the return to power of U.

With leaders from the world's biggest economies converging on Rio de Janeiro for a two-day G20 summit starting Monday, the usually relaxed seaside city is under a tight security blanket.Many locals were planning to leave the city of six million during the summit.

Diplomatic tensions over global warming will take centre stage at the G20 summit in Brazil this week. Heads of state arriving in Rio de Janeiro on