Record Summer Heat Linked to Climate Change Claims Thousands of Lives

Quick Summary

• The summers of 2023, 2024, and 2025 are officially the hottest on record globally, attributed mainly too human-caused climate change.
• Climate change has significantly fueled heat waves, leading to thousands of excess deaths; in European cities alone during summer 2025, an estimated 68% of heat-related deaths were caused by climate change.
• Global average temperature for June-August in 2025 was 0.47°C above the reference period (1991-2000), ranking as the third hottest summer after those of 2023 and 2024.
• NOAA reported that summer temperatures in the Northern Hemisphere exceeded the century’s average by over one degree Celsius.
• CO2 levels reached a record high at approximately 420 ppm in recent years compared to preindustrial levels of around 280 ppm.
• All ten hottest years on record have occurred since 2010 due to greenhouse gas concentration increases from human activities like fossil fuel combustion.
• A study highlights how younger generations will face exponentially more heat waves with longer durations unless notable emission reductions occur.