Chinese carbon-capture grass cited as tool against climate change

A hardy, fast-growing grass known as lyu xin (green heart) is being hailed as a new addition to the world's arsenal in the fight against climate change.

The grass can grow 5 meters in two months and acts like a carbon sponge, capturing much higher levels of carbon dioxide than trees, said Lei Xuejun, director of the Carbon Cycle Research Center at the Central South University of Forestry and Technology in Hunan province.

Lei, who is in Paris this week for the global climate change conference, COP 21, first cultivated the hybrid grass in 2013 and continues to lead the research. The long-term affects of the grass are still being studied.

Hunan's Changsha county was quick to identify the potential of the grass as part of its zero-carbon strategy. Over the past two years, Changsha has allocated over 20 hectares for planting lyu xin and given Lei's team financial support to optimize the carbon-capture vegetation.

Similar in appearance to sugar cane or sorghum, the grass can with stand high temperatures, drought and poor soil. It regrows rapidly after cutting, and can grow three to five times a year. The crop can be ground and processed into standard carbon products like paper, construction materials and fertilizers. Every hectare of grass can absorb over 200 metric tons of carbon dioxide every year, whereas trees absorb 15 tons annually, the China Quality Certification Center said.

The grass can lower the cost of carbon capture and storage, and reduce the concentration of carbon dioxide in the atmosphere, said Xu Heping of the Ministry of Science.

There are, however, downsides to the grass. The speed at which it grows could have negative side effects, as invasive species have been shown to unsettle the ecological balance, said Wang Guangjun, a professor of ecology and Lei's colleague, told a Hunan newspaper.

Tan Xiaofeng, a botanist at the university who specializes in woody plants, also voiced reservations. Generally speaking, he said, the carbon absorption of grass is much weaker than woody plants. As such, the actual effects of the grass will still need to be proven over a longer period of time, Tan said.

Changsha hopes that by expanding the grassland and reducing carbon emissions, the industrial county will achieve zero-carbon growth, said Yang Yiwen, Party chief of the county.