Scientists on Monday said 2025 ranked as one of the three hottest years on record worldwide as they assessed global temperature data that showed how human-driven climate change pushed long-term warming beyond the 1.5 degrees Celsius threshold set in the 2015 Paris Agreement.
Researchers from multiple climate-monitoring institutions reported that global average surface temperatures in 2025, compared with preindustrial levels, rose to near-record highs that they said reflected the combined influence of greenhouse gas emissions and natural climate variability.
The scientists said their analysis showed that the three-year global temperature average ending in 2025 exceeded 1.5 degrees Celsius above preindustrial levels for the first time since governments adopted the Paris climate accord in 2015.
Climate experts explained that the Paris Agreement, which nearly 200 countries adopted in 2015, aims to hold the increase in the global average temperature to well below 2 degrees Celsius above preindustrial levels and to pursue efforts to limit the increase to 1.5 degrees Celsius.
The researchers used historical temperature records, satellite observations, and climate models to compare recent conditions with average global temperatures from the late 19th century, which they defined as the preindustrial baseline.
The scientists said they attributed most of the observed warming in 2025 and in the three-year period to human activities, including the burning of fossil fuels such as coal, oil, and natural gas, as well as deforestation and other land-use changes that increase concentrations of heat-trapping gases in the atmosphere.
