A farmer walks in the damaged rice field caused by saltwater intrusion at Thanh Phu District of Ben Tre province in the Mekong Delta region of Vietnam, on May 15, 2013. With an area of 3.9 million hectares and a population of about 17.5 million people, the Mekong delta is the most vulnerable location in Vietnam to impacts of climate change including long lasting and deep flood, drought, tropical storms, erosion along the sea embankments. [Xinhua]