Hundreds of people marched through Mexico City on Friday calling on governments across the world to take urgent action against climate change, as UN climate talks continued in the Mexican city of Cancun.

Meanwhile at the conference, a bloc of Latin American countries issued a stern warning to rich nations that unless they commit to new emissions cuts, the talks will fail.

Earlier this week, Japan said it was not interested in negotiating an extension of the Kyoto Protocol binding emission targets, arguing it was pointless unless China and the US, the world's largest polluters - also accepted the accords.

Tarek Bazely reports on how, even if an international deal on reducing climate change is reached now, scientists say it may be too late.