This article documents notable events, research findings, scientific and technological advances, and human actions to measure, predict, mitigate, and adapt to the effects of global warming and climate change—during the year 2025.
Global average surface temperatures, shown here for each January since 1940, reached a record high temperature of 1.75
°C in January 2025 despite the Earth being in a
La Niña
(regional cooling) phase.
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1
]
Hansen
et
al.
(2025) wrote that the IPCC had underestimated aerosols' cooling effect, causing it to also underestimate
climate sensitivity
(Earth's responsiveness to increases in greenhouse gas concentrations).
[
2
]
In what Hansen called a
Faustian bargain
, regulation of aerosols improved air quality, but aerosols' cooling effect became inadequate to temper the increasing warming effect of greenhouse gases—explaining unexpectedly large global warming in 2023-2024.
[
2
]
