China gripped by unusual cold spell - China.org.cn

Ding said global warming is not only driving up the temperature, but also causing frequent extreme weather events such as drought and extreme cold.

Aside from global warming, surface cooling of oceans and weaker sun can cause temperatures to drop, he added.

In January, about 42 meteorological monitoring stations saw record-breaking low temperatures.

In Shenyang, Liaoning province, the unusual cold has driven up the number of patients with colds and respiratory complaints by at least 30 percent in the past week, said Wang Lijie, a doctor at Shengjing Hospital.