Obama: Tackle climate change or face doomsday

US president Barack Obama planned to hike a melting glacier and paint a doomsday scenario if climate change isn’t dealt with fast.

Entire nations submerged underwater, cities abandoned and refugees fleeing in droves as conflict breaks out across the globe.

It is a harrowing image of a future that Obama insists is inevitable unless the world follows his and America’s lead by making sweeping cuts to greenhouse gases.