East Asia: intense water deficits to persist from yangtze gorges through guizhou

29 November 2022

THE BIG PICTURE
The 12-month forecast for East Asia through July 2023 indicates widespread, intense water deficits in the Yangtze Watershed, Southeast China, and Taiwan. Deficits will be exceptional at the intersection of Guizhou, Chongqing, Hubei, and Hunan, and in Jiangxi, Fujian, and much of Taiwan. In the south, deficits will reach into the Pearl River Watershed, but surpluses are forecast from southern Guangdong through Hainan.

In the Yellow River Basin (Huang He), surpluses of varying intensity are expected and in much of the North China Plain and Shandong Peninsula. Northeast China, too, can expect surpluses in many regions including exceptional surpluses from northwestern Liaoning into Inner Mongolia and western Jilin. Deficits are forecast from northern Hebei into Inner Mongolia, and widespread exceptional deficits from western Inner Mongolia into Xinjiang Uygur and northern Qinghai. In Tibet (Xizang), surpluses are forecast for many areas in the west and exceptional surpluses along parts of the Yarlung (Brahmaputra) River. Central Tibet can expect moderate deficits.

On the Korean Peninsula, surpluses will cover North Korea and a pocket south of Seoul, but moderate deficits are predicted for pockets in the south. Japan can expect deficits from Shikoku into southern Honshu, and surpluses from Honshu’s northern tip into coastal Hokkaido. In Mongolia, deficits will be widespread and intense in the south and west, exceptional in many areas. Transitional conditions are forecast in the east and surpluses in the Onon River region of the northeast near the Russian border.

FORECAST BREAKDOWN
The 3-month time series maps below show the evolving conditions in more detail.

The forecast through January 2023 indicates that deficits in the Yangtze River Basin will remain exceptional from the Yangtze Gorges through the Wu River Watershed, a southern tributary, diminishing gradually in intensity in surrounding regions. In Southeast China, deficits ranging from moderate to severe are forecast and exceptional deficits will persist in Taiwan’s southern half. Moderate surpluses will linger in southern Guangdong and Hainan, and surpluses in Yunnan will shrink as deficits emerge. Widespread surpluses are expected to continue in the many regions in the Yellow River Basin, and in the North China Plain, Shandong Peninsula, and Northeast China. Areas with a forecast of exceptional surplus include the Lower Yellow River region and northwestern Jilin. Surpluses will increase in Shaanxi. Deficits of varying intensity will increase in central and western Inner Mongolia and well into Xinjiang Uygur. In Tibet, surpluses will persist in the west and emerge in the east while deficits persist in between. In North Korea, widespread surpluses will persist, severe to extreme. Deficits are expected in southern South Korea and will emerge in southern and eastern Japan, intense in Shikoku. Surpluses will linger in Honshu’s northern tip. In Mongolia, widespread deficits are forecast in the south and west, surpluses in the north-central region and Hentiyn Mountains, and mixed conditions in the east.

From February to April, deficits in Southeast China will downgrade, becoming mild to moderate overall and moderate to exceptional in Taiwan. From the Yangtze Gorges through the Wu River Watershed and into Sichuan, deficits will be severe to exceptional. Surpluses will shrink in Guangdong and Hainan. Widespread surpluses of varying intensity will persist in the Lower and Middle Yellow River Watershed, Shaanxi, North China Plain, Shandong Peninsula, and Northeast China, shrinking slightly in the Northeast. Deficits from northern Hebei into Inner Mongolia will persist but the extent of intense deficit will shrink. A few isolated pockets of deficit will persist from western Inner Mongolia into Xinjiang Uygur and deficits in Mongolia will shrink and downgrade considerably. Tibet will continue to see some surpluses in the east and west and deficits in the central region. In North Korea, surpluses will shrink considerably. Deficits will shrink in South Korea, but persist in southern Japan, downgrading in Shikoku while intensifying elsewhere. Surpluses will retreat from far northern Honshu and emerge in western Hokkaido.

The forecast for the final three months – May through July – indicates near-normal conditions in the Yangtze Basin, Southeast China, Taiwan, and South China. Deficits are forecast in northern Guizhou and nearby regions to the north, and the Upper Yangtze region into Tibet. Pockets of intense deficit are forecast in western Inner Mongolia and the Hangayn Mountains in Mongolia. Surpluses will shrink in Northeast China, Shandong, and the North China Plain, but persist with intensity at the intersection of Shaanxi, Shanxi, and Inner Mongolia. Surpluses are also forecast in Qinghai and western Tibet. Some moderate deficits are predicted for northern Japan and near-normal conditions in Korea.

Please note that WSIM forecast skill declines with longer lead times.

IMPACTS
Experts recently warned of threats to global food security as China looms closer to experiencing mass water shortages after a record-breaking drought over the summer. In addition to human consumption, water is also a critical resource for agricultural irrigation and generation of electricity from coal. China is a major manufacturing hub for alternative power industries such as wind turbines and electric vehicle batteries, and experts warn that any disruption to the nation’s exports would impact global supply chains and technologies to manage climate change. Although the Chinese government has made efforts to maintain availability, the country is still at risk of facing a supply gap that some experts anticipate to reach 25% by 2030.

Communities in South Korea are experiencing severe water shortages as a result of prolonged drought. Wando County in South Jeolla is among the many regions that have been most severely affected, with water reservoirs that provide residents with tap and drinking water reaching critically low levels. The Geumil Reservoir, a major reservoir, has reached as low as 4.3 percent of its capacity, prompting officials to minimize public use of the reservoir for only two days a week. A total of 1,390 locals rely on the Geumil Reservoir for their water supply, and as of November 25th, 2022, only have enough water to supply them for the following eighteen days.

NOTE ON ADMINISTRATIVE BOUNDARIES
There are numerous regions around the world where country borders are contested. ISciences depicts country boundaries on these maps solely to provide some geographic context. The boundaries are nominal, not legal, descriptions of each entity. The use of these boundaries does not imply any judgement on the legal status of any territory, or any endorsement or acceptance of disputed boundaries on the part of ISciences or our data providers.

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