Group 1 - The article discusses the extreme heat wave affecting multiple countries in the Northern Hemisphere, with temperatures exceeding 43°C in Spain and Portugal, and over 40°C in parts of West Asia and North Africa [2][6][10] - In China, the average temperature reached 21.1°C by June 25, 2025, marking the highest level since 1961, with predictions indicating temperatures in North China could exceed 42°C for over 30 days [6][10] - The World Meteorological Organization links these high-temperature events to the "heat dome" phenomenon, which is characterized by a persistent high-pressure system trapping heat in a specific area [10][11] Group 2 - The "heat dome" acts like a stubborn "goalkeeper," preventing cold air from entering, which leads to rising temperatures and extreme heat conditions [3][11] - The formation of the "heat dome" is influenced by three main factors: the inability of warm air to rise, descending air currents that enhance solar radiation, and prolonged dry weather that decreases soil moisture, creating a feedback loop that exacerbates heat [13][29] - The phenomenon is a natural occurrence, but its frequency and intensity are increasing due to global warming, posing significant challenges for humanity [13][26][29] Group 3 - The article highlights the critical threshold of wet bulb temperature at 35°C, which is considered the maximum temperature and humidity combination that the human body can withstand [14][19] - When wet bulb temperature reaches 35°C, it indicates that sweat cannot evaporate effectively, leading to a risk of heat-related illnesses and potentially death [16][19] - Research indicates that for every 1°C increase in temperature, the risk of death related to cardiovascular diseases increases by 2.1% [19][26]