SEA CHANGE FOR DESERTS

According to Sinopec’s post on Sina Weibo, the flooded oil field is in the Yuqi region of Northwest China’s Xinjiang Uygur Autonomous Region, where some 300 square kilometers was affected. The waters washed out roads, collapsed power lines and submerged vehicles and oil drilling equipment. Experts attributed the unseasonal flood to global warming and warned that extreme weather events will increase in the future. They left many wondering whether such flooding will become regular and how it will influence the desert’s ecology. 　

According to Sinopec, snowmelt from the nearby mountains and a rainstorm that hit the nearby Tianshan Mountains caused the flood. 　

Meteorological authorities issued a red alert for the rainstorm on July 20, warning that parts of Kashgar, the Kizilsu Kyrgyz Autonomous Prefecture and the Aksu Mountains would see moderate to heavy rains later that day. The forecast predicted 40-80 millimeters of rainfall for areas that see an annual average of 100 millimeters. 　

From the middle of July on, weather forecasts predicted high temperatures and wildfire weather in the region. 　

Researchers from the Xinjiang Institute of Ecology and Geography (XIEG), Chinese Academy of Sciences, described the Taklamakan flood as an extreme weather event caused by global warming. 　

Released on August 4, China’s recent “Blue Book on Climate Change” by the National Climate Center supported this conclusion, saying the world’s average temperature rose by 1.2 C compared to the average between 1850 and 1900. China’s average surface air temperature rose at a rate of 0.26 C per decade from 1951 to 2020, the report said. 　

China’s glaciers are melting. In 2020, the eastern and western branches of Urumqi Glacier No.1 in the Tianshan Mountains receded by 7.8 and 6.7 meters. The report revealed that China’s annual average precipitation has increased 5.1 millimeters every 10 years for the past six decades, with rainstorms becoming more frequent. 　

“Most regions in Xinjiang are arid and snowmelt from the mountains is the primary water source, especially in July and August when temperatures rise,” Duan Weili, a researcher at XIEG, told NewsChina. “The rainstorm and snowmelt caused the [latest] flood. In fact, floods have been more frequent in Xinjiang in recent years,” he added. 　

The city of Hami in Xinjiang experienced a sudden torrential rainstorm in July 2018 that ended with 20 people dead and another eight missing. 　

“The old poem that says ‘Spring wind never comes to Yumen Pass’ is no longer true,” Duan said, referencing the ancient desert outpost along the Great Wall located 80 kilometers northwest of Dunhuang, Gansu Province. “The northwestern areas now see much more rainfall. Actually, precipitation in northwestern China has been increasing these years,” Duan said. 

　

Data on weather.com.cn shows that over the past 60 years, average temperatures in Xinjiang have increased by 0.3 C annually and precipitation has increased by 10 millimeters each year. 

　

“The increased precipitation in areas surrounding the Taklamakan in recent years is because of extreme weather like rainstorms that produce what would normally be one to two years of rainfall in a day. But since overall precipitation there remains low, these changes have not made a tremendous impact on the dry climate,” Duan said.　

“One or two floods in the short term are not strong enough to change the extreme dry climate in the desert,” Jiang Fengqing who also works with the XIEG, told NewsChina, adding that the desert is poor in storing water because of its high evaporation rate. 　

“Historically, several short periods of increased precipitation improved local climates in the short term, but they did not change the general climate of the desert,” he said. 　

According to Jiang, global warming will likely promote glacier melt and increase rainfall, which could benefit areas surrounding the glaciers. But given the desert’s vast area, the increase is merely “a drop in the bucket” and will be far from enough to change the climate of the entire area. 　

“Global warming is increasing worldwide, but it differs according to region,” he said. 　

Zhou agrees. Although some experts found the climate in Xinjiang is turning from warm dry to warm wet, Zhou has observed no obvious changes in the Taklamakan Desert. 　

Duan warned that while rainfall is increasing, temperatures are rising. “I should note that temperatures and heat waves are increasing with the growth of extreme precipitation,” he said. 

“I think the influence of evaporation may be much greater than that from the increasing humidity brought about by rainfall,” he added. 　

Following the Taklamakan flood, netizens discussed whether global warming would make the area more habitable, thus restoring it to its former prosperity. 　

In the centuries spanning the Han and Tang dynasties (202 BCAD 907), 36 Central Asian kingdoms flourished in the areas along the Silk Road west of Yumen Pass. Over the centuries, the kingdoms fell to wars and less hospitable climates. 　

Experts say it is unlikely. “If precipitation levels return to those during that period, it may lead to local changes, but from what we see from models and observatory data, the rainfall increases are far from reaching such a scale,” Jiang said. 　

Jiang said that short-term water accumulation would not have a long-term impact on drought-resistant animals and plants. 　

Zhou agreed. “The water may help some moisture-loving seeds hidden in the soil grow, but once the water evaporates, those plants will gradually die,” he said. “But the wetter soil may help prevent desertification,” he added. 　

All the interviewed experts said that the flooding will influence human activity in desert areas, such as dams built in arid northwestern regions for water storage, irrigation and hydroelectric generation. As global warming continues, experts warned these dams are at risk of collapse and must be redesigned for greater capacity. 　

Duan said that increased precipitation may cause far greater damage in desert regions where many are ill-prepared for floods. 　

His warning follows the torrential rainstorm that ripped through Henan Province and killed 302 people, 292 of whom were in the capital city Zhengzhou. Media reports said that many northern cities like Zhengzhou were not as prepared for floods as southern cities where storms and typhoons are more frequent. Zhengzhou, for example, did not install sturdy-enough retaining walls for subways like southern cities, and despite the advance red alert warning, the local government was reluctant to close schools and businesses. 　

Following the rainstorm in Henan Province, China’s Development and Reform Commission issued an urgent document ordering regions to carry out the highest level emergency response immediately in cases of extreme weather. 　

“In drought-stricken areas, there is less data about extreme precipitation, so we should first improve the early-warning system and then our emergency response and management. Meanwhile, we have to increase flood prevention awareness to shed the prevailing idea that floods will never come to the Taklamakan Desert, one of the world’s driest areas,” Duan said.