Day one of the world’s biggest climate change summit ever and the stark message coming from Copenhagen is a deal must be reached to save the planet.Some 15,000 activists from more than 190 countries are in the Danish capital for the two weeks of talks. With many scientists saying the world is heating up because of man-made carbon emissions the warning from the summit’s Executive Secretary was clear. ‘‘Time is up, people are speaking out. We’ve spent two years negotiating and now this process must deliver. And what we heard in the conference room this morning is that countries want to deliver a strong and ambitious outcome in Copenhagen,” said Yvo de Beor. Children at the conference held boxes containing some 10 million signatures pleading world leaders to come up with a rescue plan. Despite pledges by nations to cut their carbon output big question marks still remain over whether a successor to the Kyoto Protocol will be found. Earlier, delegates were treated to a cataclysmic film highlighting the growing danger of rising temperatures and sea levels.