BEIJING (Reuters) - A glacier that is one of the largest at the source of China's Yangtze River is fast retreating because of climate change, state media said.

The Jianggudiru Glacier on Geladaindong Mountain in a remote part of the western province of Qinghai has shrunk 34m over the past six years, Pu Jianchen, a researcher at the Chinese Academy of Sciences, told the Xinhua news agency.

The glacier started to shrink slowly in the 1970s, then expanded between 1989 and 1994 before retreating more quickly from 1995, Pu said, Xinhua reported late on Tuesday.

Yang Xin, president of the Green River Environmental Protection Association, told Xinhua the glacier retreated 2m a year in the 1980s and 1990s but about six metres a year over the past several years.

"This is direct evidence of global climate change," he said.

Pu said the Yangtze would get more water in the short term as that glacier and others melt, but eventually no more water would flow from them.

China, the world's biggest greenhouse gas emitter, has promised to bring greenhouse gas emissions to a peak by "around 2030" as part of its commitments to a global pact to combat global warming, signed in Paris last year.