Xinhua: Climate change is a major contributor to the widespread heat waves across the globe this year and will cause more extreme weather in the future if the issue remains unresolved, a US expert on climate change has warned. A multitude of cities around the northern hemisphere have been sweating in an unusually hot summer this year, including Shanghai, Paris and Los Angeles. The sweltering heat, often accompanied by droughts and floods, brought about losses in lives and properties. One fundamental cause...