The Tarim basin in Xinjiang, China is a valley the size of Venezuela; bigger than California, New Mexico and Florida put together. On the surface it is home to Taklimakan, China’s biggest desert, but deep beneath lies a hidden ‘ocean’ that is thought to contain up to ten times more water than all the Great Lakes combined, storing more carbon than all the plants on the planet put together. While more water may sound like a good thing, researchers believe that if this carbon were to escape into the atmosphere, we would be in serious, serious trouble.“Never before have people dared to imagine so much water under the sand. Our definition of desert may have to change,” he told the South China Morning Post. “We were after carbon, not water,” Li explained. For ten years he has been studying the phenomenon of “missing carbon” in the atmosphere in the Tarim basin: the carbon seems to vanish into thin air and the scientists have spent years trying to figure out where it goes. “This is a terrifying amount of water, our estimate is a conservative figure — the actual amount could be larger”, said Professor Li Yan, who leads a research team at the Xinjiang Institute of Ecology and Geography in Urumqi, the Xinjiang capital.