Global warming "good" northern China? The opposite may be true

Henan, Shanxi and other places have suffered heavy rains one after another, causing flood disasters and causing serious losses.

Global warming is one of the major crises facing mankind now, but some people have put forward a different point of view: they believe that this is not a crisis for China, but a "positive", including "it is very likely to reproduce the temperature of the Han and Tang Dynasties, the Yellow River Basin has restored a large amount of vegetation throughout the north, the rainfall has increased significantly, and a large number of Gobi and deserts have become livable lands", "The northward migration of elephants in Yunnan is a good omen, indicating that the current climate is more like the Han and Tang Dynasties", Yunyun.

But can these beautiful expectations really come true? The frequent natural disasters in northern China in 2021, including the recent floods in Shanxi, tell us that warming is not as good as they think, but will bring more extreme weather and natural disasters; northern China, especially the northwest region, is the first to bear the brunt.

This summer, Henan and Zhejiang received the most precipitation in the same period of history since 1961, with Beijing being the third most, and Ningxia receiving the least precipitation since 1961. Drought has occurred in the eastern part of the southwest region, south China, and the eastern part of the northwest region. 丨National Climate Center, References[4]

The warming now is not the same as in the Sui and Tang dynasties

Researchers believe that during the Sui and Tang dynasties, China had a relatively warm period, but the extent of the warmth is still controversial. For example, from the eastern temperature change curve proposed by Professor Wang Shaowu of Peking University, the climate 1,000 years ago was not significantly higher than today; ge Quansheng, a researcher at the Institute of Geography of the Chinese Academy of Sciences, proposed that a small number of years of average temperature in the past two thousand years may be higher than today, but only a few tenths of a degree higher. Lü Peng, deputy director of the Science and Technology Archaeology Center of the Institute of Archaeology of the Chinese Academy of Social Sciences, said that the temperature in the Sui and Tang dynasties may be slightly higher than it is now, but it will not be outrageous that the entire northern climate is as warm and humid as the current Jiangnan region.

To be sure, the warming period during the Sui and Tang dynasties and the current warming are very different in nature: today's climate change is no longer a "natural law", but caused by human behavior, and the warming rate is much faster than in the past.

The assessment report of the United Nations Intergovernmental Panel on Climate Change (IPCC) states:

· Global temperatures over the past decade have averaged about 1.1°C higher than in 1850-1900.

· Each of the last 40 years has been warmer successively than any previous 10 years since 1850.

· Since 1970, global surface temperatures have risen faster than at any time in the previous 2,000 years or more.

· The concentration of carbon dioxide in the atmosphere is now at its highest level in the past 2 million years.

In other words, the current atmospheric and climate change characteristics are no longer comparable to those of the Sui and Tang dynasties.

Deserts become oases: human effort is key

The article "Climate Change benefits China" argues that the increase in desert vegetation is due to warming and increased precipitation, but this is not the case – deserts become oases mainly by human efforts, and even if increased rainfall is beneficial, the effect is very limited.

Zhou Tianjun, a researcher at the Institute of Atmospheric Physics of the Chinese Academy of Sciences, previously said in an interview with Intellectuals that as far as precipitation in Xinjiang is concerned, the overall trend is increasing, of which summer is the most significant, and the central value increases by 2.5%-3.5% every 10 years; but since entering the 21st century, the change has been stable and the increase trend is not as significant as in the previous period. Zhou Tianjun stressed that due to the low amount of precipitation in the region,the pattern of Xinjiang's arid climate will not change.

Zhang Qiang, chief engineer of the Gansu Meteorological Bureau and director of the Key Open Laboratory of Drought, Climate Change and Disaster Reduction of the China Meteorological Administration, also said that precipitation in the northwest region is indeed increasing, but the increase in precipitation is very limited. He said that in recent decades, China's vegetation construction and climate change have been carried out simultaneously, and it is not possible to judge whether human factors or environmental factors dominate. We have seized such an opportunity and made arduous and sustained efforts to create the results of vegetation restoration and ecological improvement.

As for the "resurrection" of some desert rivers, Chen Yaning, a researcher at the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences and director of the State Key Laboratory of Desert and Oasis Ecology, once mentioned in an interview with "Intellectuals" that recently, some of the rivers that have been cut off from the lower reaches of the river and the "resurrection" of lakes are mainly caused by artificial ecological water transmission in the past 20 years, and are not due to "local climate changes, increased precipitation, and desert changes in Jiangnan" as exaggerated by many self-media articles.

That is to say, whether it is the restoration of vegetation in northwest China or the improvement of water resources, it mainly depends on the construction of our ecological project. These improvements are clearly not something that can be achieved by waiting for a warming climate.

Elephant herd migration is also unsubstantiated

Some articles use the distribution of Asian elephants to argue for climate change from ancient times to today, but this argument is also unreliable.

Lu Peng, an associate researcher from the Center for Science and Technology Archaeology of the Institute of Archaeology of the Chinese Academy of Social Sciences, introduced to Guo Hu that the natural distribution of Asian elephants in history can indeed reach the Yellow River Basin, but in the past two thousand years, the shrinking of Asian elephant habitats to the south is not entirely because of climate, but there are many human factors. One of the most important reasons for the shrinking of the elephant's habitat is farmland reclamation, which is also related to the human pursuit of ivory products. In other words, the southward migration of Asian elephants in the past two thousand years does not prove that China's climate has changed significantly.

Of course, this is not to say that environmental change has no impact, but human activities dominate the impact. Leaving aside the influence of humans and considering only the temperature index, even during the Ming and Qing dynasties and even today, it is possible for Asian elephants to survive in the area south of the Huai River Basin. As for the northward migration of the elephant herd in Yunnan this year, the elephant herd originally had the habit of migrating, and the current evidence does not prove that the northward migration of the elephant herd is dominated by climate change.

Climate change will bring more disasters

According to some articles online, the current warming will bring about a humid and mild environment. But the reality is simply not so rosy: climate change will bring more extreme weather and natural disasters.

For example, with the warming of the climate, the temporal and spatial distribution of precipitation is more uneven than in the past, such as extreme precipitation in Henan, Shanxi and other places this year and drought in Gansu and other places.

The polarization of precipitation may cause a period of sustained drought in an area and a period of heavy precipitation, resulting in a parallel drought and flood disaster in the same region in the same year. Researcher Zhou Tianjun mentioned that since the 21st century, the number of heavy precipitation events in Xinjiang has also increased significantly, with the number of rainstorm days increasing by 12% every 10 years and the amount of rainstorms increasing by about 13% every 10 years.

Zhang Qiang said that China's northern region, especially the northwest region, is an important climate-sensitive area, and the impact of climate change on these areas will be more obvious. For example, although the overall frequency of sandstorms in the northwest region is decreasing, the persistence is stronger. Qilian Mountains and other places could have used meltwater from snowy mountains to balance precipitation distribution and ensure water supply, but under the background of warming climate, the melting rate of snow and ice in snowy mountains in summer is accelerating, which is more likely to induce snowmelt flash floods.

From the perspective of agriculture, on the one hand, drought and flood disasters will directly affect agricultural production, on the other hand, drought and other climates are also prone to diseases and insect pests, further affecting agricultural production. In addition, under the background of climate change, the frequency and extent of meteorological disasters such as typhoons and high temperature heat waves will increase accordingly.

We cannot fall into environmental determinism, and human action is the key

Historically, climate change and social development have indeed been linked. For example, Ge Quansheng and others have made statistics on the temperature, wars, droughts and floods in China's historical period, and found that social changes generally have the law of "cold and warm". Historically, economically developed and population growth often occurs in the warm period on a centennial scale, and when the climate changes from warm to cold, it is more likely to occur social unrest.

Ge Quansheng pointed out that the rapid social development that accompanies the warm period will increase the pressure on the society's demand for resources and the environment, resulting in increased social vulnerability. When the climate turns cold, agricultural production is affected and societies with increased vulnerability are more likely to fall into crisis.

But social development is not entirely determined by climate. Lü Peng emphasized: First, climate change itself does not directly determine the decline of a dynasty; it is extreme climate and natural disasters that directly affect human production and life; second, the rise and fall of dynasties is essentially dominated by people, and if there is a good social system to resist natural disasters, climate change may not be able to make this dynasty decline. What's more, with the advancement of technology, the ability of human beings to cope with environmental changes has been much higher than in ancient times.

As Deputy Director Lu Peng said: "In the same environment, different human behaviors will cause different results, and we must avoid falling into 'environmental determinism' and ignoring human power." The environment is only a stage built by the earth, and whether the performance is good or not depends on the person himself. ”