Why do extreme weather conditions such as freezing in the south and drought in the north occur frequently?

“It was so dry in the first half of the year, we suffered from major floods in the middle of the year, and now it’s raining, snowing, and freezing!” On January 11, an elderly Miao ethnic minority in Huaping Township, Leye County, Guangxi, was walking hard on the ice road. He Qiangji told reporters, "I have lived for more than 60 years, and I have never seen so many changes in the sky!"

Standing on the ice road in Huaping Township and looking out, I saw a vast expanse of ice and snow, and the southern mountains. A "Northern Landscape". Affected by the combination of strong cold air and low warm and humid air flow, the area has suffered from freezing rain and snow disasters since January 3.

At this time, drought is raging in North China. Since September 23 last year, Shandong, the second largest wheat-producing area in my country, has experienced a cumulative average rainfall of 11 mm, 86% less than the same period in normal years. 60.95 million acres of farmland have been affected by drought in the province, and 53% of wheat fields are still affected by drought.

Chen Zhenlin, spokesperson of the China Meteorological Administration, said that in early 2008, my country experienced the abnormal phenomenon of "drought in the north and freezing in the south", and it happened again after two years. Last year was the year with the greatest frequency, intensity and impact of extreme weather events in our country in the past ten years.

Experts such as Song Lianchun, director of China’s National Climate Center, believe that climate anomalies in the northern hemisphere originate from the cold Arctic wind, while the southern hemisphere is currently mainly troubled by the La Ni?a phenomenon with cold sea surface temperatures. Polar cold air continues to spread southward, strongly affecting countries and regions in mid- and high-latitudes. Moreover, during the same period, there was no obvious southerly warm and humid air flow northward, nor was there easterly wind bringing water vapor from the eastern sea. Therefore, it was difficult for precipitation to form in North China and the Huanghuai River, resulting in large-scale drought.