More than 31,000 scientists have signed a petition denying that man is responsible for global warming. The academics, including 9,000 with PhDs, claim that greenhouse gases such as carbon dioxide and methane are actually beneficial for the environment. The petition was created in 1998 by an American physicist, the late Frederick Seitz, in response to the Kyoto Protocol a year earlier. It urged the US government to reject the treaty and said: "The proposed limits on greenhouse gases would harm the environment, hinder the advance of science and technology, and damage the health and welfare of mankind." It added: "There...