Why is the summer of 2022 so extreme?
China News Weekly Reporter/Peng Dani Intern/Du Xi
Published in China News Weekly magazine on August 29, 2022, No. 1058
Recently, when Tu Jianjun contacted an alumnus living in Vancouver, Canada, he told him that he had to install air conditioning at home this summer because the weather was too hot, which made him impressed by the impact of extreme high temperature weather around the world this year.
Tu Jianjun is the President of China at the Agora Energy Transition Forum and the former Director of the China Cooperation Department of the International Energy Agency, where he studied and worked in Vancouver. Vancouver has a mild climate and pleasant seasons, and public information shows that the summer temperature in this city on the southwest coast of Canada is generally around 20 °C in summer and above 0 °C in winter. But in late July, temperatures in Vancouver reached 30.4°C, the hottest day on record.
In an article in early August, Nature wrote that extreme heat is playing out almost simultaneously in many parts of the world.
In South Asia, regions of India and Pakistan have been hit by high temperatures since March. Parts of India exceeded 44°C at the end of March, with at least 90 people dying as a result; In June, Tokyo exceeded 35°C for nine consecutive days, the worst heatwave recorded there since the 1870s; In mid-July, the UK experienced its first high temperature above 40°C since it began monitoring temperatures. At the same time, droughts and wildfires under the heat wave spread in France, Spain, Greece, Germany and other places.
This series of extreme events in many parts of the Northern Hemisphere is the embodiment of the rapid 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 evolving significantly, which has brought new challenges to the development of human society.
Europe suffered its worst drought in 500 years
In Spain, archaeologists have recently made an unexpected discovery, and a group of prehistoric stones known as "Spanish Stonehenge" has been revealed. Originally covered by the Val de Canas Reservoir in the central Cáceres province, the water level has dropped due to the worst drought in decades, which authorities say has fallen to 28 percent of the reservoir's capacity.
As a result of the drought, the Danube, Europe's second-longest river, has fallen to one of the lowest levels in nearly a century, exposing more than 20 German warships that sank near the Serbian section of the river, Prahovo, during World War II; Italy has declared a state of emergency around the Po River, and in late July, fishermen spotted a bomb left over from the submerged World War II, weighing 450 kilograms, in the bare waters of the country's longest river.
Drought has profoundly affected europe's food, shipping, energy and other fields. In the town of Kaub, in the middle reaches of the Rhine, there is an ancient water level measuring station where any captain entering the upper Rhine will refer to the recorded water level. After 12 August, its water level scale dropped below 40 centimeters, meaning that the water level was no longer suitable for most boats.
Originating in the Alps, the Rhine is the largest river in Western Europe and is also known as the "lifeline" of the European economy, and commodities such as food, coal and chemicals rely on this important transport route to reach their destinations.
For Germany, 80% of its waterway transport is done on the Rhine. Because of the falling water level in the Rhine, Holger, vice president of the German Confederation of Industries, said in a statement in mid-August that it was only a matter of time before chemical or steel plants were closed, mineral oils and building materials such as oil could not reach their destinations, and large and heavy transport could not continue.
Tu Jianjun told China News Weekly that in the context of this year's Russian-Ukrainian conflict, the European energy market is already in a state of high tight balance. At present, the EUROPEAN Union is multi-pronged trying to get rid of its high dependence on Russian gas imports as soon as possible, and Europe is also actively stepping up its energy reserves for the winter. Now, shipping, including coal transportation, is severely affected by high temperatures and droughts, making Europe's energy supply security even more challenging.
Andrea, a researcher at the European Commission's Joint Research Centre for collecting data for the European Drought Observatory, said on Aug. 9 that while a retrospective and comprehensive analysis was needed, much of Europe was experiencing what could be the worst drought in 500 years.
In 2018, Europe suffered a very extreme drought, but that year, wet conditions in southern Europe compensated for crop harvests. Instead, Andrea said in an interview with the media that much of Europe has faced both heat waves and droughts this year, "Based on my experience, I think this year may be more extreme than 2018." ”
According to data released by the European Drought Observatory on Aug. 3, 63 percent of the land in the EU and the UK is now in a state of drought "warning" or "alert," involving almost the same size of land as India.
In France, only 9.7mm of precipitation fell in July this year, the lowest in July since 1959. On August 5, France's Minister of Coordination for Ecological Transformation and Land, Besch, said that there was no drinking water in the water supply pipes of more than 100 french municipalities, which needed to rely on water tankers for water supply, and he did not rule out the possibility of distributing bottled water in the most difficult areas to reach.
In its latest report, published on July 25, the European Commission's Joint Research Centre for Scientific Services predicts that eu maize, sunflower and soybean production will fall by 8 to 9 percent due to hot and dry summers.
Nearly half of the world's olive oil is produced in Spain. According to the Wall Street Journal reported on August 17, olive oil prices were pushed higher due to concerns that the hot, dry weather in Spain would affect the olive harvest this season. Kyle Holland, a market analyst at data provider Mintec, said the market price of extra virgin olive oil in Spain has risen by about 7 percent over the past month. Unless the weather conditions in Spain improve rapidly in the coming weeks, olive oil production, which enters the harvest season in October, will fall by almost 30%.
Days of drought and scorching heat make 2022 the worst year of wildfires in Europe. The London Fire Department said it had dealt with 340 outdoor fires in the first week of August, more than eight times the number recorded in the same period last year. Spain, the country most affected by forest fires in Europe this year, has seen dozens of wildfires this year, burning a total of 244,000 hectares of land, almost four times the average annual wildfires have burned since 2006 was recorded.
According to the European Forest Fire Information System (EFFIS), nearly 660,000 hectares of land were burned by wildfires on the european continent between January and mid-August this year, 56 percent higher than the previous peak, the 420,000 hectares recorded in the same period in 2017, which is equivalent to one-fifth of Belgium's land area. Some analysts pointed out that according to the current trend of wildfire outbreaks, more than 1 million hectares of land burned in Europe this year.
In addition, a report in the US media "Politician" in early August pointed out that the magazine conducted a preliminary analysis of the data released by several National Bureaus of Statistics in Europe and found that Germany, Spain, Portugal, the Netherlands and other countries recorded thousands of deaths in the extreme heat wave in July.
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 a mild climate, cool summers, frequent precipitation and relatively uniform distribution, so the tolerance for high temperature and drought is low, and the relevant equipment and infrastructure are not sound. The high temperature and drought in 2022 have a great impact on the social economy and the daily lives of people.
People and nature are altered by hot weather
Drought usually occurs with high temperatures. Li Chao, a senior scientist at the Max Planck Meteorological Institute in Germany, works in Hamburg, Germany, which, in terms of latitude, is close to the Mohe River, the northernmost point of China. The highest summer temperatures here are usually within 33°C, however, on July 20 this year, the highest temperature ever observed here: 40.3°C.
"In the summer of 2022, there will be high temperature and drought events in many parts of the northern hemisphere, especially in the western United States, western and southern Europe, and a large part of China." Li Zhaoxin pointed out that each region has its own particularities, and the changes in specific meteorological elements are also different, but they are closely related to the atmospheric circulation anomaly, especially the intensity and location of the subtropical high pressure in the northern hemisphere, which plays a crucial role.
Li Chao told China News Weekly that in the summer, the entire mid-latitude region of the northern hemisphere of the world is controlled by a high-pressure system, as a sinking air flow, which is not conducive to the formation of clouds, and the corresponding weather is high temperature and little rain. The recent high temperatures and droughts in southern China are the subtropical high pressures in the western Pacific Ocean, and on the European continent, the North Atlantic high pressure.
However, in normal years, typhoons from the ocean, storm cyclones at high latitudes, etc. will bring warm and humid gases and rainfall, reducing the intensity of the impact of subtropical high pressure in the mid-latitudes, and this year, the subtropical high pressure lasts longer and the intensity is more pronounced.
In addition to Europe, the United States also witnessed the country's third hottest July, while the Copernicus Climate Change Service project observed that antarctic sea ice area reached the lowest level in July in 44 years of satellite data records.
However, under the climate change, the double attack of high temperature and drought is not an exception that has 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, located between latitudes 47° N and 55° N, is a northern temperate zone in terms of climate, and during the many years he has lived here, Lu Mengji said, rarely exceeding 30°C in summer heat, and sometimes even reaching 37°C in recent years. 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 stock in Europe, with one-fifth of the houses built before 1919, poor heat insulation and limited air circulation.
Similarly, in the past, houses in Germany were originally designed for insulation because it was cold in winter, but now, after climate change, heat dissipation in summer is a big problem. Lu Mengji said that now when the temperature is high during the day, it is necessary to close the curtains of the room to avoid the sun, and in some cases, people also need to live on the basement floor of the house to temporarily avoid the high temperature. Air conditioning, a rare appliance that German families rarely need, is also gradually beginning to appear, and this year, Lu Mengji's neighbor has installed air conditioning when he renovates the house.
When temperatures rise in areas that were originally farther north of latitude, the ecosystem as a whole struggles to adapt to this shift. When tending his garden, Lu Mengji found that in the past, many plants originally sprouted in April and May, but now they are advanced to March, and then in the cold tide weather, these young shoots cannot survive. Often hiking outdoors and in the forest, he also observed that many artificial coniferous forests are dehydrated, resulting in a decline in the ability to secrete pine resin that can deal with pests, trees are more susceptible to insect pests, and the leaves are yellowed and fallen in large areas.
Behind 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 in the United States, pointed out in an interview in response to China News Weekly that scientific studies have shown that under the climate change caused by human factors, the most affected extreme events have a basic hierarchy. Observations, physical studies, and computer simulations have yielded evidence that some anomalies are definitely related to climate change.
Specifically, the most directly related extreme event of climate change is the heat wave, which is sure to increase dramatically as the world warms; The climate events in the back line are floods and storm surges in coastal areas, droughts, wildfires... Finally, hail and tornadoes. "The evidence is clear that the more coal, oil and gas burn, the more the planet warms up and the more likely it is that any particular location will 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, due to the ongoing high temperatures, the melting area of Alpine glaciers could hit a record high for at least 60 years, according to foreign media reports; In July, temperatures in the Arctic Circle soared to 32.5 degrees Celsius, and scientists in the Arctic even played ice volleyball in short-sleeved shorts.
On 18 May 2022, the World Meteorological Organization released the State of the World's Climate Report 2021, announcing that the average world temperature today is 1.11°C higher than before the Industrial Revolution, clearly showing that we are in a warming world. However, Vicki Thompson, a climate scientist at the University of Bristol in the United Kingdom, told China Newsweek that this is not an equal change, and the rate of warming varies from region to region.
On August 11, an article published in Nature Communications – Earth and the Environment analyzed observations from the Arctic Circle over the past 43 years and found that the Arctic is warming faster than previously thought. Specifically, much of the Arctic Ocean warmed at a rate of 0.75°C per 10 years between 1979 and 2021, which is almost four times the global average.
The warming Arctic, in turn, is involved in global climate change in a complex way. At present, a hot issue in the climatology community is how the melting of sea ice in the Arctic and Antarctic will exacerbate high temperatures and droughts in the mid-latitudes, especially on 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 have a summer impact, such as the deadly heat wave in Russia in 2010.
In fact, Europe is indeed a "hot spot" in the Northern Hemisphere that has been hit more by heat waves, breaking the heat record more than once in the past five years. In an interview with Nature in early August, Kay Cohenhuber, a climate scientist at Columbia University, said his team found that Western Europe is very prone to heat waves: Over the past 40 years, Extreme Heat has occurred in Western Europe three to four times more frequently than in other mid-latitude regions of the Northern Hemisphere.
Changes in atmospheric dynamics from Arctic warming are one possible explanatory mechanism, but it is still an inaccurate scientific hypothesis. Specifically, Li Chao, a senior scientist at the Max Planck Institute of Meteorology in Germany, explained that this theory believes that the European continent relies on the rapids axis of the Arctic to bring cold and humid air from the middle and high latitudes to the European continent. However, as arctic temperatures rise, the temperature gradient between the polar regions and the lower and middle latitudes becomes smaller, and the intensity of the rapids axis weakens. Li Zhaoxin does not particularly agree with this mechanism, preferring to see it as a manifestation of a complex climate system rather than a causal relationship.
Li Chao said that the increase in greenhouse gas emissions, how much the global warming is ample, and what kind of climate will be brought in under what scenario, such issues have been fully studied; The more difficult question now is how greenhouse gases will affect the entire atmospheric circulation and what kind of weather it will bring, and weather information is very critical to social response. Given carbon dioxide emissions in 2070 and the corresponding socio-economic development scenario, he cites, the current study can roughly predict the magnitude of the global temperature increase that year, but it cannot predict what the weather will be like on the European continent in the summer of 2070.
Li Zhaoxin also said that the specific form, performance, quantitative intensity of extreme weather in the region, as well as the time and process of the arrival of events and other more accurate issues, there are still great uncertainties and scientific debates. However, climate scholars say that two points are clear, one is that climate change will increase global temperatures, and the other is that extreme weather in the future, such as some unexpected high temperature events, will become more and more frequent.
In Europe, according to the IPCC, about half of the European population could be at risk of high or very high heat response in the summer by 2050. On August 15, a new peer-reviewed study by the First Street Foundation, an American research institute, predicted that by 2053, more than 100 million Americans will live in the "extreme heat zone," at least one day a year, and the high temperature index will exceed about 52 degrees Celsius. The high temperature index is an indicator of the combined air temperature and humidity, which refers to the temperature felt by the body.
"Greenhouse gas emission reduction is also a fundamental measure to deal with climate change", Li Chao pointed out, understanding the impact of extreme weather and how to deal with extreme weather is also important, in this regard, in addition to climatologists, social sciences and other interdisciplinary disciplines should also join in the joint efforts.
Source: China News Weekly