Scientists have criticised China's bulldozing of hundreds of mountains to provide more building land for cities.



In a paper published in journal Nature this week, three Chinese academics say plan to remove over 700 mountains and shovel debris into valleys to create 250 sq km of flat land has not been sufficiently considered “environmentally, technically or economically.”

Li Peiyue, Qian Hui and Wu Jianhua, all from the School of Environmental Science and Engineering at Chang’an University, China, write: “There has been too little modelling of the costs and benefits of land creation. Inexperience and technical problems delay projects and add costs, and the environment impacts are not being thoroughly considered.”



One of the largest projects began in April 2012 in Yan'an in the Shaanxi province, where the aim was to double the city's area by creating an additional 78.5 sq km of land.



Local officials expect the project to generate billions of yuan from the sale or lease of the new land and spare agriculture land elsewhere in the country, which otherwise may have been used for development.



Soil erosion increases the sediment content of local water sources. In Shiyan, Hubei province, pounding hills into valleys caused landslides, flooding and altered water courses. This had serious implication for the city as it lies close to the headwaters of the South-North Water Transfer project, an endeavour to divert river waters along channels to Beijing.

In Lanzhou, Gansu province, work was temporarily halted because of air pollution levels caused by dirt from the excavation. No one had thought to damp the soil to stop it flying in the wind.



Mountain top removal has been performed before, especially in the strip mines of the eastern United States, but nothing has been performed on the scale of the Chinese earthworks.



The authors conclude that full environmental impact reports are needed along with economic assessments of the cost and benefits of the proposed works. They write: “Where there is no profit, governments should be dissuaded from going ahead.”