Climate change poses a serious challenge to human society and it is believed that humans are themselves to blame. The Intergovernmental Panel on Climate Change has concluded that, with high confidence, human activities are responsible for the continuing rise of global mean surface air temperature since the 1950s.

An article recently published in Nature Sustainability showed that human influence on climate change can be traced back to the late 19th century based on summer-winter temperature difference.

This research was carried out by scientists from the Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, in collaboration with leading experts on climate research from the UK and Germany.

"It is well known that humans are driving global warming, but when did this begin?" said the lead author, Dr. DUAN Jianping. "Our study has shown that anthropogenic influence on climate change started much earlier than we previously believed."

Anthropogenic climate change usually focuses on the rise of surface air temperature, namely global warming, and the increase of climate extremes. 

The scientists found that the amplitude of seasonal temperature fluctuations has been decreasing widely, and this trend can be traced back to the late 19th century. They found that temperature seasonality had been stable until the 1860s, from which there have been continuous downward trends across northern hemisphere mid-high latitudes.

A formal detection and attribution analysis using the latest climate model simulations showed that increased greenhouse gas concentrations and anthropogenic aerosols were the main contributors to the observed downward trends.

Graphic illustration for the anthropogenic-induced decrease in the difference of summer and winter temperatures. The thermometers represent the difference between summer and winter temperatures. (Image by DUAN Jianping)