Why is the summer of 2022 so extreme?
China News Weekly reporter / Peng Danni intern / Du Xi
Published in the 1058th issue of "China News Weekly" magazine on August 29, 2022
Recently, when Tu Jianjun contacted an alumni living in Vancouver, Canada, the other party told him that this summer, because the weather was too hot, he had to install air conditioners at home, which made him deeply impressed by the impact of this year's extreme high temperature weather around the world.
Tu Jianjun is the President of Agora Energy Transformation Forum China and the former Director of the China Cooperation Department of the International Energy Agency. He studied and worked in Vancouver.
Vancouver has a mild climate and pleasant four seasons. Public information shows that the temperature in this city on the southwestern coast of Canada is generally around 20°C in summer and above 0°C in winter.
But in late July, Vancouver hit 30.4C, the hottest day on record.
The "Nature" magazine wrote in an article in early August that the extreme heat is happening almost simultaneously in many parts of the world.
In South Asia, India and Pakistan have been hit by high temperatures since March this year.
Parts of India exceeded 44°C at the end of March, killing at least 90 people; in June, Tokyo exceeded 35°C for nine consecutive days, the worst local heatwave since records began in the 1870s; The first high temperature above 40°C since the start of monitoring the temperature.
At the same time, drought and wildfires under the heat wave spread in France, Spain, Greece, Germany and other places.
This series of extreme events that occurred in many places in the northern hemisphere is a reflection of the drastic changes in the global climate.
In the future, the meteorological community predicts that there will be more and more unexpected extreme weather.
Scholars who study meteorology point out that the earth's climate environment is changing significantly, which brings new challenges to the development of human society.
Europe suffers worst drought in 500 years
In Spain, archaeologists have recently made an unexpected discovery, revealing a prehistoric rock group known as "Spanish Stonehenge".
Stonehenge was originally covered by the Valdecanas Reservoir in the central province of Cáceres, but the water level has dropped due to the worst drought in decades, and authorities say it has dropped to 28% of the reservoir's capacity.
Due to drought, the water level of the Danube, the second longest river in Europe, has dropped to one of the lowest levels in nearly a century, and more than 20 German warships sunk near the city of Prahovo in the Serbian stretch of the river during World War II have also been exposed; Italy has declared a state of emergency around the Po River. In late July, in the exposed waters of a section of the riverbed of the country's longest river, fishermen found a submerged bomb left during World War II, weighing 450 kilograms. heavy.
The drought has profoundly affected Europe's food, shipping, energy and other fields.
In the town of Kaub on the Middle Rhine, there is an old water level measuring station, and any captain entering the upper Rhine will refer to the water level recorded here.
After August 12, the water level scale value dropped below 40 cm, which means that the water level is no longer suitable for most ships to pass.
The Rhine, which originates from the Alps, is the largest river in Western Europe and is also known as the "lifeline" of the European economy. Commodities such as food, coal and chemicals rely on this important transportation route to reach their destinations.
For Germany, 80% of its water transport is done on the Rhine.
Due to the drop in the water level of the Rhine, Holger, vice president of the Confederation of German Industry, said in a statement in mid-August that the closure of chemical or steel plants, the inability of petroleum and other mineral oils and construction materials to reach their destinations, the large volume of transportation And heavy transport can't go ahead, it's just a matter of time.
Tu Jianjun told China News Weekly that under the background of the Russian-Ukrainian conflict this year, the European energy market is already in a state of high tight balance.
At present, the EU is trying to get rid of its high dependence on Russian natural gas imports as soon as possible through a multi-pronged approach, and Europe is also actively stepping up its energy reserves for winter.
Now, shipping, including coal transportation, is severely affected by high temperature and dry weather, making Europe's energy supply security facing even greater challenges.
Andrea, a researcher at the European Commission's Joint Research Centre in charge of collecting data for the European Drought Observatory, said on August 9 that although a comprehensive retrospective analysis is required, most of Europe is experiencing what may be the worst in 500 years. drought.
In 2018, Europe suffered an extreme drought, but the wet conditions in southern Europe made up for the crop that year.
On the contrary, most of Europe is facing a heatwave and drought at the same time this year, Andrea told the media. "Based on my experience, I think this year may be more extreme than 2018."
According to data released by the European Drought Observatory on August 3, 63% of the land in the European Union and the United Kingdom is now in drought "warning" or "alert" status, covering an area almost as large as India.
In France, the precipitation in July this year was only 9.7mm, which was the least precipitation in July since 1959.
On August 5, French Minister of Ecological Transformation and Territorial Coordination Besch said that there is no drinking water in the water supply pipelines of more than 100 French towns and cities, and these towns need to rely on water tankers for water supply. the possibility of distributing bottled water in regions.
The EU's production of maize, sunflower and soybeans will fall by 8% to 9% due to a hot and dry summer, the European Commission's Joint Research Centre for Science Services said in its latest report forecast published on July 25.
Nearly half of the world's olive oil is produced in Spain.
Olive oil prices have been pushed up on concerns that Spain's hot, dry weather will affect this season's olive harvest, The Wall Street Journal reported on August 17.
Market prices for Spanish extra virgin olive oil have risen about 7 percent in the past month, said Kyle Holland, a market analyst at data provider Mintec.
Unless Spanish weather conditions improve quickly in the coming weeks, olive oil production heading into the harvest season in October is set to drop by nearly 30 percent.
Days of drought and scorching heat waves make 2022 the worst year for wildfires in Europe.
The London Fire Service said it had dealt with 340 outdoor fires in the first week of August, more than eight times the number recorded for the same period last year.
Spain is the country most affected by forest fires in Europe this year. Since the beginning of this year, dozens of wildfires have broken out in Spain, burning a total of 244,000 hectares of land, almost four times the average annual wildfire since records began in 2006.
According to the European Forest Fire Information System (EFFIS) data, between January and mid-August this year, wildfires on the European continent burned nearly 660,000 hectares of land, 56% higher than the previous peak of 420,000 hectares recorded in the same period in 2017 , which is equivalent to one-fifth of the land area of Belgium.
Some analysts pointed out that according to the current trend of wildfire outbreaks, more than 1 million hectares of land will be burned in Europe this year.
In addition, a report by the American media "Politico" in early August pointed out that the magazine conducted a preliminary analysis of data released by several European national statistical offices and found that Germany, Spain, Portugal, the Netherlands and other countries were in the extreme heat wave in July. Thousands of deaths have been recorded cumulatively.
Li Zhaoxin, a researcher at the French National Research Center and a dynamic meteorologist, said in an interview with "China News Weekly" that Western European countries usually have mild climates, cool summers, frequent and evenly distributed precipitation, so their ability to withstand high temperature and drought is low, and related equipment and infrastructure is not very sound.
The high temperature and drought in 2022 will have a great impact on the social economy and people's daily life.
People and nature changed by hot weather
Droughts are often accompanied by high temperatures.
The city where Li Chao, a senior scientist at the Max Planck Institute of Meteorology in Germany, works in Hamburg, Germany, is close to Mohe, the northernmost city in China, in terms of latitude.
The maximum temperature in summer here is usually within 33 ℃, however, on July 20 this year, the highest temperature ever observed here: 40.3 ℃.
"In the summer of 2022, high temperature and drought events will occur in many places in the northern hemisphere, especially in the western United States, western and southern Europe, and the vast areas of China." Li Zhaoxin pointed out that each region has its own particularity, and changes in specific meteorological elements also They are different, but they are all closely related to atmospheric circulation anomalies, especially the intensity and location of the subtropical high in the northern hemisphere, which play a crucial role.
Li Chao told China News Weekly that in summer, the entire mid-latitude region of the northern hemisphere is controlled by high-pressure systems. As a downdraft, it is not conducive to the formation of clouds. The corresponding weather is high temperature and little rain.
It is the subtropical high in the western Pacific that has recently affected the high temperature and drought in southern China, and the high in the North Atlantic on the European side.
However, in usual years, typhoons from the ocean, storm cyclones in high latitudes, etc. will bring warm and humid gases and rainfall, reducing the intensity of the impact of the subtropical high in the mid-latitudes. This year, the subtropical high lasts for longer days and stronger. obvious.
In addition to Europe, the United States also saw its third hottest July in the country, while the Copernicus Climate Change Service observed that Antarctic sea ice extent reached the lowest July in the 44-year satellite data record value.
However, under climate change, the double attack of high temperature and drought is not an exception that only appeared this year.
Lu Mengji, a Chinese scholar who has lived in Germany for 40 years, told China News Weekly that Germany has now experienced high temperatures every year for three or four consecutive years.
Germany is located about 47°N to 55°N latitude, and belongs to the north temperate zone in terms of climate. In the many years of living here, Lu Mengji said that the high temperature in summer rarely exceeds 30 °C, and in recent years, it sometimes even reaches 37 °C.
This brings a new set of challenges to life.
Countries such as the UK, Germany, Spain, Italy and Greece were not used to the threat of extreme heat. For example, between 2013 and 2019, only 3% to 5% of households in the UK were equipped with air conditioning, and the UK also has the oldest housing in Europe. In stock, one-fifth of the homes were built before 1919 with poor insulation and limited air circulation.
Similarly, houses in Germany in the past were originally designed for thermal insulation, because it was colder in winter, but now, after climate change, heat dissipation in summer is a big problem.
Lu Mengji said that when the temperature is high during the day, it is necessary to draw the curtains in the room to avoid the sun. In some cases, people also need to live in the basement of the house to temporarily avoid the high temperature.
Air conditioners, a household appliance rarely needed by German families, have gradually begun to appear. This year, Lu Mengji's neighbors had installed air conditioners when they renovated their houses.
When the temperature in those latitudes that were originally more northerly warmed, the entire ecosystem had difficulty adapting to the shift.
When taking care of his garden, Lu Mengji found that in the past, many plants germinated from April to May, but now they have advanced to March, and then encountered cold weather, these buds could not survive.
He has also observed that many artificial coniferous forests are short of water, which reduces the ability to secrete turpentine, which can deal with pests. The trees are more susceptible to pests, and the leaves turn yellow and fall in large areas.
behind the extreme weather
Li Zhaoxin pointed out that it cannot be said that the high temperature and drought event in 2022 is a manifestation of global warming.
However, based on the current research conclusions of the academic community on the climate system and the analysis of mathematical statistics and simulations, it can be said that the probability of global high temperature and drought events this year has increased in the context of global warming.
Scott Denning, a professor of atmospheric science at Colorado State University, pointed out in an interview with China News Weekly that scientific research shows that under the climate change caused by human factors, the most affected extreme events have a basic level structure.
Evidence from observations, physical studies, and computer simulations suggests that some unusual weather must be linked to climate change.
Specifically, the extreme events most directly related to climate change are heat waves. With global warming, heat waves will definitely increase sharply; the next climate events are, in order, floods and storm surges in coastal areas, droughts, wildfires… ...and finally hail and tornadoes.
"The evidence is clear that when more coal, oil and natural gas is burned, the more the planet warms and the more likely it is for any given location to experience a heat wave," he said.
Due to climate change, most of the world's mountain glaciers are receding, and many countries near the Arctic are experiencing abnormally high temperatures.
At the end of July, according to foreign media reports, the melting area of glaciers in the Alps may reach a record high in at least 60 years due to the continued high temperature weather; Playing ice volleyball in short-sleeved shorts.
On May 18, 2022, the World Meteorological Organization released the "State of the World Climate Report 2021", announcing that today's world average temperature has been 1.11 °C higher than before the Industrial Revolution, clearly showing that we are in a gradual warming in the world.
However, Vicky Thompson, a climate scientist at the University of Bristol in the United Kingdom, told China News Weekly that this is not an equal change, and the rate of warming varies in different regions.
On August 11 this year, an article published in "Nature Communications-Earth and Environment" analyzed the observation data of the Arctic Circle over the past 43 years and found that the rate of warming in the Arctic is higher than previously thought.
Specifically, most of the Arctic Ocean warmed at a rate of 0.75°C per decade between 1979 and 2021, which is almost four times the global average.
The warming Arctic, in turn, is involved in global climate change in complex forms.
At present, in the climatology community, a hot research question is how the melting of sea ice in the north and south poles will exacerbate the high temperature and dry weather in the middle latitudes, especially the European continent.
In 2015, a paper published in the journal Science mentioned that in addition to exacerbating winter storms and cold waves, Arctic warming will also bring shocks to summer, such as the deadly heat wave in Russia in 2010.
In fact, Europe is indeed the "hot spot" in the northern hemisphere that has been hit by more heatwaves, breaking heat records more than once in the past five years.
In an interview with Nature in early August, Columbia University climate scientist Kay Cohenhuber said that his team found that Western Europe is very prone to heat waves: Over the past 40 years, the frequency of extreme heat in Western Europe has been higher than that of other mid-latitude regions in the northern hemisphere. 3 to 4 times.
Changes in atmospheric dynamics due to Arctic warming is a possible explanation mechanism, but it remains an imprecise scientific hypothesis.
Specifically, Li Chao, a senior scientist at the Max Planck Institute for Meteorology in Germany, explained that this theory holds that the continental European region relies on the jet stream axis in the Arctic region to bring cold and humid air from the middle and high latitudes to the European continent.
However, as the Arctic air temperature increases, the temperature gradient between the poles and the lower and middle latitudes becomes smaller, and the strength of the jet axis appears to weaken.
Li Zhaoxin does not particularly agree with this mechanism. He prefers to think that it is a manifestation of the complex climate system rather than a causal relationship.
Li Chao said that the increase in greenhouse gas emissions has been fully researched on how much the global temperature will increase and what kind of climate will it bring under what scenarios; the more difficult problem now is that greenhouse gas After the increase, it will affect how the entire atmospheric circulation will be affected and what kind of weather will it bring, and weather information is very critical to social response.
For example, given the carbon dioxide emissions in 2070 and the corresponding socio-economic development scenarios, current research can roughly predict the magnitude of the global temperature increase in that year. However, it is impossible to predict what the European continent will look like in the summer of 2070. weather.
Li Zhaoxin also said that there are still many uncertain factors and scientific debates about the specific shape, performance, and quantitative intensity of extreme weather in the region, as well as the timing and process of the event.
However, climatologists said that two points are relatively clear, one is that climate change will increase the global temperature, and the other is that extreme weather in the future, such as some unexpected high temperature events, will occur more and more frequently.
In Europe, by 2050, around half of the European population could be at high or very high risk of heat response in summer, according to the IPCC.
On Aug. 15, a new peer-reviewed study from the First Street Foundation, a U.S. research organization, predicts that by 2053, more than 100 million Americans will be living in "extreme heat zones" for at least one day a year, The high temperature index will exceed about 52°C.
The high temperature index is an indicator of comprehensive air temperature and humidity, which refers to the temperature felt by the body.
"Greenhouse gas emission reduction is still a fundamental measure to deal with climate change," Li Chao pointed out. It is also important to understand the impact of extreme weather and how to deal with extreme weather. In this regard, in addition to climatologists, social sciences and other interdisciplinary disciplines should also join Come in and work together.
"China News Weekly" Issue 32, 2022
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