Heat wave sweeps the world

Extreme heat waves have been repeated in many parts of the world recently, with high temperatures breaking historical records in some places, threatening people’s health, agricultural production and the ecological environment. The reasons for this, in addition to short-term direct meteorological factors, experts generally believe that long-term climate change has led to more frequent extreme heat events. In recent years, the scientific community has proposed a concept that defines a new era reflecting the impact of human activities as the “Anthropocene”, and climate change can be considered as a wake-up call to this era. There are stories of heat waves hitting the globe almost every summer in recent years. This year, Europe’s July heat was particularly prominent. The UK Met Office issued its first-ever red alert for abnormally high temperatures in mid-July. London Heathrow Airport reached a record-breaking 40.2 degrees Celsius on the 19th. The French meteorological department said that 64 cities in France broke the local record high temperature on the 18th. Klaus Reinhardt, president of the German Physicians’ Association, mentioned the impact of this heat wave in Europe: “Extreme heat can cause people to become ill, while heat stress and high ground-level ozone levels can also have a serious impact on human health.” The French health authorities said, “There has been a significant increase in the number of medical visits by people during the heat wave for reasons such as hypothermia and dehydration.”

In addition, Hungarian Agriculture Minister Naji István told the media on the 26th that Hungary is suffering from an “unprecedented” drought. So far, 690,000 hectares of crops have been damaged. Due to the water shortage, corn and sunflowers in some areas only grow to knee height. The Danube, the largest river flowing through Hungary, has only 40% of its average volume. Slovenia’s ecology has also been tested by the country’s hottest summer on record, with severe mountain fires in the third week of July and more than 500 people evacuated from eight villages as of the 22nd.

In the Americas, the U.S. National Weather Service Weather Forecast Center reported on July 19 that more than 100 million people across the country are under various types of heat warnings.

In Asia, South Korea’s hot weather came earlier this year. The authorities raised the heat warning from “caution” to “alert” level on July 2, 18 days earlier compared to last year.

Even in the southern hemisphere, which is still winter, is also affected by high temperatures. The survey of the New Zealand Institute of Atmospheric and Water Resources shows that the territory’s snow line is rising. The agency released data on July 20 that the average temperature of 15 degrees Celsius across New Zealand from January to June 2022, 1.2 degrees Celsius higher than the average value of the same period from 1981 to 2010, the second hottest on record.

Deep climate causes

Meteorological observations can provide a direct, short-term explanation for the cause of this global heat wave. For example, the French meteorological service said that a low-pressure system initially located between the Azores and mainland Europe moved toward the Bay of Biscay and became a source of intense heat by absorbing hot air that had been present over the Iberian Peninsula for a week. The Korea Meteorological Administration analyzed that the high pressure of the North Pacific Ocean spread near the southern part of Jeju Province from late June, and the strong inflow of hot and humid southwesterly winds along the edge of the North Pacific High Pressure made the temperature higher than previous years.

Experts generally agree that long-term climate change caused by human activities is the underlying cause. “Climate change will lead to more and more extreme weather,” said Yifang Zhu, a professor in the Department of Environmental Health Sciences at the University of California, Los Angeles.

Radhika Khosla, associate professor at the Smith School of Enterprise and the Environment at the University of Oxford, UK, said in an interview, “Science shows that climate change has led to an increase in the frequency and scale of extreme heat waves in recent years, with an additional 475 million heatwave exposure events observed globally in 2019 compared to 1986 to 2005 (i.e. a person experiencing three or more days of extreme high temperatures).”

Lee Hyun-ho, a professor at the Department of Atmospheric Science at Korea Gongju University, said that the earth’s temperature has risen by about 1.3 degrees Celsius compared to the pre-industrial period, resulting in a general environment where heat is more frequent.

Alarm bells ringing for Anthropocene development

The tremendous impact of human activity since industrialization has, in the view of many scientists, brought Earth’s history into a new era – the Anthropocene. According to the Anthropocene Working Group of the International Union of Geological Sciences (IUGS), this concept emphasizes the “significant increase in human impact since industrialization”, including global warming, sea level rise, ocean acidification, etc.

Although there are still some debates about the specific starting point and the connotation and extension of the Anthropocene, there is no doubt that climate change caused by the burning of large amounts of fossil fuels and the emission of greenhouse gases by human beings is an important feature of it.

The message of the United Nations climate conferences shows that if we do not strengthen actions such as emission reduction, the Anthropocene will be waiting for us again and again like the previous or worse climate disasters. When the UN Intergovernmental Panel on Climate Change adopted the report of Working Group III in its sixth synthesis report in April this year, it said that the world was at a crossroads of “lost opportunities” and that if action was taken, it would still be possible to reduce global greenhouse gas emissions by at least half by 2030 compared to 2010, and to achieve the Paris Agreement’s goal of halving global warming. The world is at a “crossroads” and if action is taken, it is still possible to reduce global greenhouse gas emissions by at least half by 2030 compared to 2010 and achieve the Paris Agreement’s goal of keeping global warming to 2 degrees Celsius and aiming for 1.5 degrees.

The Commission plans to issue its sixth synthesis report late this year or early next year. The fifth synthesis report, last completed in 2014, gave a strong boost to the international community in reaching the Paris Agreement in 2015. It is hoped that this synthesis report, and this summer’s heat wave, will give further impetus to the global response to climate change.

As WMO Secretary-General Petri Taras said recently about the July heat wave: “I hope this is a wake-up call for governments.

By Shiyue Luo