Understanding Record Heat: How Scientists Measure and Explain Extreme Temperatures

Scientists clarify that a "record-breaking heat" label depends on comparisons with past observations from a global network of weather stations, ships and buoys, with major datasets dating back to the late 19th century. They emphasize that while Earth has endured hotter periods over millions of years, today's warming is unprecedented within the span of human civilization, a conclusion drawn from climate archives such as Antarctic ice cores and tree rings.

Researchers use climate models to link elevated greenhouse gases with higher temperatures, noting that current warming is driven primarily by fossil-fuel combustion and is occurring faster than in the past million years. Attribution studies, including a recent analysis of Europe's June 2026 heat wave, show that such extremes would have been virtually impossible under pre-industrial conditions. The article also explains that heat indexes incorporate humidity and wind, with wet-bulb temperatures near 35 °C posing severe health risks, and that urban heat islands amplify temperatures through reduced vegetation and heat-absorbing surfaces. Mitigation strategies like planting trees, creating green roofs and using reflective materials can lessen city heat.