Agence France-Presse: British explorer Lewis Gordon Pugh declared Friday he had kayaked further to the top of the world than anyone else ever has, as his bid to reach the North Pole failed — much to his delight. But the renowned extreme swimmer, dubbed the human polar bear, nonetheless warned the Arctic ice pack was thinning and urged world leaders to take immediate action to halt it. Pugh, 38, made it to 81 degrees north latitude before hitting solid pack ice. He temporarily planted the flags of …