全球气温记录的维护和验证由多个权威机构承担。[1]美国戈达德太空研究所、美国国家环保信息中心和英国气象局哈德利中心分别维护着全球最完整的三个数据集，这些数据集的记录可追溯至1880年。[1]更为久远的参考数据来自中英温度数据系列，其连续温度记录始于1659年，是世界上最古老的同类记录。[1]此外，科学家还利用南极钻取的冰芯档案来研究更深层的气候历史，这些冰芯记录跨越超过100万年。[1]
极端高温事件的成因复杂多样。约5600万年前，大量碳进入大气，可能来自火山活动和海洋沉积物释放的甲烷，曾引发过一个全球变暖时期。[1]在当代，欧洲2026年6月经历的热浪被认为是所研究地区有记录以来最严重的，科学家指出1976年出现相同温度水平几乎不可能再发生。[1]除了温度数据本身，湿度等因素也显著影响人体对热的感受。当湿球温度达到约35摄氏度（95华氏度）时，即使人处于阴凉处休息或保持充足水分，身体仍可能出现过热。[1]
Scientists maintain comprehensive temperature records spanning more than a century to verify claims of record-breaking heat.[1] The three most complete global datasets are managed by the U.S. Goddard Institute for Space Studies, the U.S. National Centers for Environmental Information, and the United Kingdom's Met Office Hadley Centre, with records dating back to 1880.[1] Beyond instrumental measurements, researchers also rely on longer historical archives—the Central England Temperature series represents the world's oldest continuous temperature record, beginning in 1659, while ice cores extracted from Antarctica contain climate data spanning over one million years.[1]
Understanding extreme heat events requires examining both immediate conditions and longer-term climate patterns.[1] Approximately 56 million years ago, massive quantities of carbon entered the atmosphere, likely released through volcanic activity and methane from ocean sediments, triggering a period of global warming.[1] More recently, a severe heat wave affected Europe in June 2026, marking the most extreme event on record for the studied regions, with scientists noting that temperatures of similar magnitude in 1976 would have been nearly impossible under those conditions.[1] Beyond air temperature alone, the sensation of heat depends on humidity levels; when wet-bulb temperature reaches approximately 35 degrees Celsius (95 degrees Fahrenheit), the human body can overheat even in shaded rest with adequate hydration.[1]