Report Summary

During the past three months (December, January, and February), the effects of human-induced climate change — mainly from burning coal, oil, and methane gas — were evident in most regions of the world, particularly in the form of extreme heat. This analysis uses Climate Central’s Climate Shift Index (CSI) to determine the influence of climate change on temperatures around the globe during this period.

The Climate Shift Index (CSI) indicates how climate change has altered the frequency of daily temperatures in any location around the world, every day. The CSI ranges from -5 to +5, where positive levels indicate temperatures that are becoming more likely due to climate change and negative scores indicate conditions that are becoming less likely. For this analysis, we computed the average per capita exposure to CSI level 2 or higher (a strong influence of climate change) for people in 220 countries. We also computed city-wide CSI signals for 940 cities.

Key findings

At least one in five people globally felt a strong climate change influence each day from December 2024 to February 2025.
Nearly 394 million people experienced 30 or more days of risky heat that were added by climate change during the last three months. Most of these people (74%) lived in Africa. Risky heat days are days with temperatures hotter than 90% of the temperatures recorded in a local area from 1991-2020. Heat-related health risks rise when temperatures climb above this local threshold.
In half of the analyzed countries (110 out of 220), the average person experienced temperatures with a strong influence of climate change for at least one-third of the season (30 days or more)
In 287 global cities, the average person experienced temperatures with a strong influence of climate change one-third of the season (30 days or more).