Al Gore urges world leaders to sign Paris climate deal

'While the deal is not enough by itself, it is a major step forward,' says former US vice president and climate campaigner during visit to Philippines

World leaders must show their commitment to tackling global warming by signing the Paris climate agreement at a ceremony in April at the United Nations, climate change activist and former US vice president Al Gore said.

Gore said there was a "tremendous push" for heads of government to formally ink the accord, to keep up momentum for the deal struck by nearly 200 countries in December and to avert the worst impacts of climate change on vulnerable nations.