President Asif Ali Zardari has stressed for using tourism as a potential economic engine, and said it is important to maintain the standards of tourist industry, and save tourists and inhabitants from facing climatic changes.  "These climatic changes are a great challenge in the path of achieving international development targets," the President said in message on 'World Tourism Day' being observed throughout the world on (Sep 27) with the theme of supporting measures adopted to prevent sudden climatic changes. The President said Pakistan is contributing in the international efforts to counter the unusual climatic changes besides taking steps for promotion of tourism. "The rich culture and the civilizations of Harappa, Moenjodaro and Gandhara which existed here, are a great source of attraction for the tourists. The Northern Areas are a tourist paradise, visited by thousands of tourists every year," he said.  Zardari said tourism in a way couldn't only highlight the beautiful planet Earth, but also generate much-needed revenue that in turn can be used to manage the threat of global climate change. He said being realized rather belatedly, climate change has the potential of radically changing people's lifestyle.