Where do we go to escape the heat in midsummer? We talked to meteorological experts about the frequent occurrence of extreme high temperatures in the climate | Global | Meteorology

Summer seems to be getting hotter and hotter.

On July 23rd, there was a heatwave. This is the last solar term of summer, when the heat accumulated and emitted on the surface reaches its peak throughout the year. In many southern regions, the peak of "humid hot steam exchange" is reached throughout the year. According to seasonal laws, the hottest period of the year has arrived. But in the past two years, the heat has become increasingly irregular.

People are seeking a cool summer retreat, and a list of "summer tourism destinations" released by the National Climate Center may provide ideas.

In 2022, a total of 37 regions in China were among the first to be awarded this national level title. Hegang City, which had previously become popular due to "cabbage housing prices," is listed as the first prefecture level city in Heilongjiang Province to receive comprehensive evaluations.

Hegang has been awarded the title of National "Summer Tourism Destination". Provided by the Propaganda Department of Hegang City

The national level "summer tourism destination" is selected by the National Climate Center, and the created indicators consist of 5 primary indicators and 37 secondary indicators. The climate conditions for avoiding heat are composed of 14 secondary indicators, which reflect the advantages of avoiding heat in terms of temperature, precipitation, humidity, wind, and human comfort.

On July 14th, the national "summer tourism destination" media promotion event in Heilongjiang Province was held in Hegang City, Heilongjiang Province. It is the midsummer season, with drizzling rain and temperatures below 20 ℃ in Hegang. Due to its location in the golden triangle area embraced by the Heilongjiang, Songhua, and Xiaoxing'an Mountains, the special geographical location and climate environment make Hegang comfortable and cool in summer.

At the recommendation meeting, Chen Yu, Chief Climate Service Officer of the National Climate Center, introduced that temperature is the most core indicator in the evaluation criteria for national "summer destinations". "The advantages of each region are also different. For example, Heilongjiang has a high latitude and lower summer temperatures, while other places may not necessarily have such low temperatures, but higher humidity. Everyone's evaluation criteria are consistent. When choosing a summer destination, temperature indicators are still the most important and are a veto indicator."

Taking Hegang as an example, its average summer temperature is 20.2 ℃, annual average temperature is 3.7 ℃, average relative humidity is 75%, and the number of days with air quality above level 2 throughout the year exceeds 350 days.

According to the revised 2023 Technical Specifications for the Demonstration Work of Creating Summer Vacation Tourism Destinations, the selection of national summer vacation tourism destinations generally requires a minimum of 10 years of long-term meteorological data.

"We conduct a comprehensive evaluation based on more than 20 climate indicators, including humidity, wind conditions, comfort, and related ecological environment indicators, such as natural landscape conditions." Chen Yu said, "We hope to use this method to help local governments explore more possibilities by utilizing their own good climate resources."

Hegang.

The list of "summer vacation destinations" was born against the backdrop of increasingly hot summers and frequent extreme weather.

On July 6th this year, the world experienced its hottest day. Only 2 days have passed since the last "hottest day in the world". According to data from the National Center for Environmental Forecasting in the United States, the global average temperature set a record for high temperatures for three consecutive times in the first week of July alone. Experts predict that due to the impact of the El Ni ñ o phenomenon, this year's record for high temperatures may continue to be broken.

Professor Li Qingxiang from the School of Atmospheric Sciences at Sun Yat sen University introduced that global warming is closely related to human activities. Especially since industrialization, global climate change has been entirely caused by human activities. The occurrence of this phenomenon not only brings people extreme heat in summer, but also increases the probability of various climate disasters.

In 2016, the Paris Agreement, jointly signed by 195 countries, set the global average temperature increase over the industrialized level for this century to be within 2 ℃, preferably within 1.5 ℃. But this century has not yet reached a quarter, and data from all over the world shows that the average temperature has been 1.09 ℃ higher than before industrialization.

"It can be said that it is already very pessimistic," Li Qingxiang said, "especially in years when encountering El Ni ñ o phenomena or other natural rate combinations, this value will skyrocket. The last time was from 2015 to 2016, and the temperature has not dropped since it rose."

The global warming caused by the El Ni ñ o phenomenon is a natural factor, and its cycle is generally 3-7 years, but it is not a strict cycle. The internal variability of the climate system has many uncertainties, making accurate forecasting quite difficult. Relatively speaking, what we can predict and control are external forcing factors, which are the factors imposed by human activities outside the natural system of the Earth.

Taking into account the average intensity, impact range, and duration of high temperature heat wave events, the comprehensive intensity of regional high temperature events in China during the summer of 2022 has reached its strongest level since complete meteorological observation records began in 1961. From June 13th to August 19th, the high temperature lasted for 68 days, with temperatures exceeding 40 degrees Celsius occurring in 28 provinces; The highest temperature at 262 national stations remained unchanged or exceeded historical extremes, surpassing those in 2013 and 2017.

"Before industrialization, the global average temperature had increased by 1.1 ℃ in a few hundred years. Although the internal variability of the climate system was relatively large, sometimes ranging from 0.5 ℃ to 0.6 ℃ in a year, the warming caused by natural factors was likely to fall back the next year. The average temperature fluctuated around the annual average temperature. However, the temperature rise caused by human activities is difficult to fall back in the short term." Li Qingxiang explained.

At present, part of the global human effort to mitigate climate change is to make efforts at the level of human activities. For ordinary people, facing the scorching heat, choosing a summer destination is a more direct need.

"Global climate change is an almost irreversible process. The probability of extreme weather is increasing, and some meteorological records are constantly being broken. The latitude of areas available for people to choose from for summer vacation is also getting higher. People's ways of vacation have also changed. Previously, people often went to the seaside in the south, but now perhaps more people choose to go north. At the same temperature, the humidity in the north is low, and compared to the south, it feels cooler in terms of body feel." Li Qingxiang said.

"Objectively speaking, due to global climate change, the cool climate in the north has become a scarce resource and may also become a new growth point. However, the Earth is still a whole, and the issue of global climate change still needs to be paid attention to and solved," said Li Qingxiang.

Perhaps when heading to summer destinations to enjoy the coolness, everyone also needs to take some time to think about energy conservation and emission reduction issues.

Junchuan Farm, Luobei District, Hegang City.

Hegang.