Press Trust of India: Ahead of the key Copenhagen meet in December to tackle global warming, leading Indian environmentalist R K Pachauri and 29 other global leaders have inked a declaration vowing to jointly work to pursue clean transportation and back national climate change legislations. “Addressing the problems caused by climate change is the greatest environmental challenge of our time,” California Governor Arnold Schwarzenegger, who was among the signatories of the declaration, said after a climate …