environmentalist and explorer Pen Hadow has commented on Prime Minister Gordon Brown?s recent speech on the environment. Mr Hadow, who lives at Hexworthy, said Mr Brown ?talked the talk? but now it was time for him to ?walk the walk? ? the comment came after Mr Brown pledged to make Britain a world leader in the battle against global warming. Mr Brown hinted he is ready to extend the Government?s target of a 60% cut in Britain?s greenhouse gas emissions by 2050, revealing that he has asked an independent committee of experts to look at the possibility of an 80% goal. Mr Hadow said: ?It has taken world leaders far too long to acknowledge that time really is running out ? despite the accumulating evidence, including the imminent disappearance of the Arctic ice-cap. ?Next year, I will deliver to world scientists a definitive survey of the thickness of the Arctic ice-cap which will determine how long there will be a permanent ice-cap at the North Pole and help prepare world leaders for the momentous global consequences of ice-cap meltdown.? In February, Pen will ?walk the walk? and set off from Point Barrow, in Alaska, on a 120-day trek to the North Pole. He will lead the Vanco Arctic Survey team, and conduct a survey of the thickness of the Arctic ice -cap, using an ice-penetrating radar. The survey aims to provide scientists around the world, with the most accurate prediction to date of the ice and snow thickness. At present, despite the best estimates of submarines and satellites, estimates of polar meltdown vary from 100 years to just 16 years from now.