Huge infrastructure projects in Tibet, among the biggest and costliest in China, are likely to be severely damaged by global warming thawing the permafrost and softening the ground that supports them, according to a study by Chinese scientists. The projects include the Qinghai to Tibet railway and a huge oil pipeline in the region, the researchers said. The study was carried out by a team led by Professor Guo Donglin at the Chinese Academy of Sciences’ Institute of Atmospheric Physics in Beijing. The researchers looked at a narrow strip of land more than 1,000km long between Qinghai province and the Tibetan plateau known as the Qinghai-Tibet engineering corridor. Most soil in the area is below freezing point the whole year round. The corridor is home to the five largest and most costly infrastructure projects on the world’s highest plateau, including a national highway from Qinghai to Tibet, the oil pipeline from Golmud to Lhasa, an optical fibre cable from Lanzhou to Lhasa, the region’s largest high-voltage power line and the rail link to Qinghai. China’s government has spent huge sums and employed millions to build the projects in some of the world’s most extreme environments. Some of projects were built before there was any perception that global warming might thaw the soil and pose a threat to their stability, such as the national highway in 1950s. Some scientists, however, raised the alert in later projects such as the rail link, but their voices were drowned out by supporters arguing for the economic, political and military benefits they would bring. Researchers have been asked to come up with methods to prolong the project’s lifespans. Some previous studies found they could stand thawing to depths of about 30cm and the most optimistic estimates said the projects could last until the end of this century. Guo and his team found that if global temperatures increase by one degree Celsius by the middle of this century, which is the best-case scenario if all nations commit seriously to reducing greenhouse gas emissions, more than a third of the area in the engineering corridor would face catastrophic thawing. If temperatures rise two degrees, existing infrastructures in more than 60 per cent of the region would collapse as the ground would become too soft to support their weight. Some areas with the heaviest human activity might begin to thaw as early as 2020, the report said. Civil engineering experts have developed various methods to deal with the sinking caused by the thawing of permafrost, such as strengthening infrastructure with crushed-rock embankments or drying up the subsurface layer with ventilation ducts. Guo’s team found that the existing methods could delay massive damage by no more than 17 years. In some areas the effectiveness of the costly remedies would last only six years, the researchers said. Their paper was published by the International Journal of Disaster Risk Science .