Heat waves have intensified in recent decades

China is experiencing more frequent and intense heat waves due to global warming, which are affecting broad regions across the country, according to a senior meteorologist.

"With the intensification of global warming, high-temperature weather in China in recent years has been characterized by its earlier onset, increased frequency, prolonged duration, a wider impact range and increased overall intensity," said Zheng Zhihai, chief forecaster at China's National Climate Center.

The average onset of high temperatures (those exceeding 35 C) has advanced by 2.5 days per decade, moving from starting around June 24 between 1981 and 1990 to starting around June 7 between 2011 and 2020, Zheng said. The frequency and impact of regional high-temperature events have also risen, from an average of 3.3 occurrences affecting 258 national meteorological stations per year between 1981 and 1990, to 4.1 occurrences affecting 328 stations per year between 2011 and 2020.

"Since the mid-20th century, the extent of climate warming in our country has been significantly higher than the global average for the same period, with a potential increase in the frequency and intensity of extreme high-temperature events becoming a new norm," he said.

Zheng said the El Nino and La Nina effects might lead to abnormal atmospheric circulation, causing regional high temperatures this summer.

The National Meteorological Center has issued high-temperature alerts for 10 days from Friday evening. From Sunday evening to Thursday evening, the center upgraded a yellow alert to orange in the three-tier warning system for high temperature. The orange alert showed that at least four provincial-level regions had experienced temperatures exceeding 37 C over the past 48 hours, with at least two of them exceeding 40 C.

The first orange high-temperature alert for the year came earlier than usual. Last year, the first orange alert was issued on June 22, and in 2022 it was issued on June 17. The national average summer temperature in 2022 was 22.3 C, the highest since 1961, followed by 22 C last year.

As of Friday, 16 national meteorological stations had surpassed their historical high-temperature records, with 228 stations reporting daily maximum temperatures exceeding 40 C.

Zheng said that so far this summer, temperatures in most parts of the country have been higher than usual, with there being more frequent and prolonged hot weather.

North, East, Central and South China and Northwest China's Xinjiang Uygur autonomous region may experience periodic heat waves, with some areas facing extreme high temperatures. Unlike in 2022, when high temperatures mainly affected the Yangtze River Basin, this year's summer temperatures have exhibited distinct periodic variations, with intense heat hitting North China and the provinces of Henan, Anhui, Shandong and Jiangsu this month. The heat is expected to move southward in July and August.

The heat wave has also increased the risk of forest fires. The Ministry of Emergency Management, the National Forestry and Grassland Administration and the China Meteorological Administration issued a yellow alert for forest fires on Thursday. Regions like Shanxi, Shandong, Henan and Hubei have experienced 50 to 80 percent less precipitation and temperatures 1 to 2 C higher than usual over the past 20 days, posing potential forest fire risks from Friday to Monday.