Pope Francis calls for urgent action on climate change in White House speech

Addressing a crowd of nearly 15,000 on the south lawn, pope invokes Martin Luther King Jr in speaking of the moral need to protect our 'common home'

Pope Francis enlisted the spirit of Martin Luther King Jr to help bolster his call for urgent action on climate change on Wednesday in a welcoming ceremony at the White House that Barack Obama said would "shake our conscience from slumber".

Speaking in front of crowd of nearly 15,000 guests that had begun packing into the south lawn before dawn, the pope wasted no time in striking an unashamedly political tone during his first public event of a six-day visit to the US.