According to monitoring data from the National Climate Center, since this autumn (September 1 to November 1), the national average temperature has been 15.0°C, 1.4°C higher than the same period in normal years, and the highest for the same period in history since 1961.

However, winter entered overnight. Rain and snow in most areas of the north on November 5 caused the temperature to drop sharply. At 0:00 on November 6, Beijing even started heating. Someone in the circle of friends joked: He warms up almost as soon as he takes off his short sleeves.

Temperatures exceeding 1.5°C will become more common in the future

2023 is a landmark year in the global climate crisis, because after 2023, the climate crisis will enter a new phase in an all-round way. Starting from the beginning of June, the global average temperature jumped upwards, breaking through all previous observation record ranges. By the beginning of November, almost every day's values significantly exceeded the previous historical observation records, and there is currently no sign of a return.

In early August this year, the European Copernicus Climate Change Service announced that the global average temperature in July reached 16.95°C, which is the highest value in the history of observation records and 0.72°C higher than the July average from 1991 to 2020. , 1.5°C higher than the July average before the Industrial Revolution (1850 to 1900). This is the first time in human history that the monthly average increase in global surface temperature has exceeded 1.5°C. Among them, in the 29 days from July 3 to July 31, the global temperature on each day exceeded the historical record set on August 13, 2016 (16.80℃). On July 6, the global temperature value It even reached 17.08℃, 1.62℃ higher than the global average temperature before the industrial revolution.

The global temperature rise will exceed 1.5°C in the summer of 2023. We need to go back further in the history of the earth to find higher temperatures, and there were no modern Homo sapiens at that time.

According to the commitments made in the 2015 Paris Agreement, countries hope to control global warming to less than 2°C by the end of this century and strive to limit it to 1.5°C. However, as the global daily and monthly average temperatures cross this mark in July 2023, temperatures exceeding 1.5°C will become more common in the future. The pressure to adhere to the Paris Agreement will increase, and global climate action will become increasingly urgent. .

November 6, 2023, Changchun, Jilin. From the evening of November 5th to 6th, Changchun City ushered in a significant rainfall that turned to heavy snowfall. IC photo

Warming affects the health and stability of the Earth's climate system

The global ocean temperature rise in 2023 has also significantly exceeded the historical record. Starting from the end of March, with the end of the La Niña event in the eastern equatorial Pacific, the El Niño-type sea temperature increase gradually appeared, and the global sea surface temperature was like a wild horse, rapidly exceeding the 2016 level. The maximum temperature during the last El Niño event of the year. From the end of March to the present, global sea surface temperatures have significantly exceeded the previous highest temperature in history, and as the winter El Niño event matures, this warming trend will continue.

Global warming is profoundly affecting the Earth's climate system. On September 19, the extent of Arctic sea ice was only 4.24 million square kilometers, 1/3 less than in the 1980s. Throughout this year, there has been very little Antarctic sea ice. Since the beginning of May, the Antarctic sea ice extent has hit a record low for the same period almost every day, and the value is far less than the historical extreme value. As of November 1, the Antarctic sea ice area was 15.7 million square kilometers, breaking the historical record for the same period in 1986.

The cryosphere is a key subsystem of the Earth's climate system, and changes in its area regulate solar radiation entering the Earth system. The polar ice and snow melt in summer and increase in area in winter. This dynamic change is like the "heartbeat" of the earth. Therefore, the continued reduction of ice and snow area will directly affect the health and stability of the entire earth's climate system.

On September 6, the World Meteorological Organization announced that June, July and August of 2023 will be the hottest June, July and August respectively on record. On the same day, United Nations Secretary-General Guterres warned: "Climate collapse has begun."

Global warming is not only a change in temperature, but also an increase in the frequency and intensity of extreme weather around the world. According to the "Human Losses Caused by Disasters 2000-2019" report released by the United Nations Agency for Disaster Prevention and Reduction in 2020, affected by global warming, in the first 20 years of the 21st century, extreme high temperature events increased by 232%, flood events increased by 134%, Storm events increased by 97%, wildfire events increased by 46%, and drought events increased by 29%.

Climate warming causes cold season to be "late"

As the Northern Hemisphere enters late autumn, temperatures begin to drop, but the climate crisis continues. At the end of October and the beginning of November, the temperature was relatively high in most parts of eastern my country. In Shandong, Henan, Inner Mongolia and other places, the temperature even increased by more than 6℃. In late autumn, when the autumn wind is supposed to be bleak, the daily maximum temperature in Beijing, Jinan, Zhengzhou, Nanjing, Shanghai, Hangzhou and other places remains above 25℃, or even exceeds 30℃, which is like the scene of early summer.

The average temperature at the Beijing Observatory in late October was 14.5°C, 3.4°C higher than the same period in normal years, and the highest temperature for the same period in history since 1961. From November 4th to 5th, the eastern region of my country ushered in a round of precipitation. However, the vast majority of North China did not see the first snow. In the normal snowfall season, you can feel the lingering autumn rain. This is a "late" cold season caused by global climate warming. the result of.

Since November 2, winter storms have hit many places in Europe. In Cap Laz, France, the maximum gust intensity reached 207 kilometers per hour, which has reached the level of a super typhoon. The local wave height reached 7 to 9 meters, and strong winds lifted roofs. Power supply and transportation were disrupted. The United Kingdom, France, Belgium and other countries therefore activated red storm warnings and entered a state of emergency. The storm caused heavy rains and floods in many places. In Tuscany, a region in central and northern Italy, more than 200 millimeters of rainfall fell in three hours, reaching a once-in-50-year level. The heavy rains caused floods, causing rivers to burst their banks and Bridges collapsed and waist-deep water flooded streets, killing many people.

As winter approaches, winter storms like this will appear across the Northern Hemisphere. Due to the huge warming in the early stage, when storms bring strong winds and cold waves, the transition between hot and cold will be more severe, which will have a greater impact on social and personal health, becoming the biggest environmental safety risk in winter.

In addition, the central and eastern equatorial Pacific is still in an El Niño state. Various research institutions and business sectors around the world predict that moderate-intensity El Niño events will continue until next spring. Affected by the El Niño event, global temperatures will continue to remain high.

As a "bad boy" that stirs up climate anomalies, El Niño events are conducive to wet and cold weather in southern North America, but can lead to droughts in northern South America, Southeast Asia, Australia and other places. For my country, El Niño will weaken the winter monsoon, leading to higher temperatures in most parts of eastern my country. Water vapor from the tropics will be more easily transported to southern my country, which is conducive to the formation of rainy and low-sun weather.

However, our country is located in the mid-latitudes and is affected not only by El Niño from the tropics, but also by weather processes in high latitudes and Eurasia. The changes are more complicated, especially when a cold wave occurs on the basis of warming, which will make people Weather changes feel more sudden and extreme. This requires us to monitor weather changes and make rolling forecasts at all times, so that we can more accurately respond to future extreme weather.

(The author is an associate researcher at the Institute of Atmospheric Physics, Chinese Academy of Sciences)