Agence France-Presse: US House of Representatives speaker Nancy Pelosi said Tuesday that the fight against climate change was a "game changer" in China-US relations, as she visited Beijing on a trip focused on energy. Pelosi, a tough critic of China’s human rights record and a vocal advocate of environmental protection, is leading a delegation from the US Congress to China on a working visit devoted to energy and climate change. "I think that this climate change crisis is a game changer in US-China …