# 2025 in climate change

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.

## Measurements and statistics

* 10 January: a summary from the Copernicus Climate Change Service stated that 2024 was the warmest year since records began in 1850, with an average global surface temperature reaching 1.6 °C above pre-industrial levels, surpassing for the first time the 1.5 °C warming target set by the Paris Agreement. The summary also stated that 2024 was the second consecutive year with the hottest global temperature, surpassing 2023 by +0.12 °C.
* 21 January: a study published in Nature Climate Change concluded that at least 30% of the Arctic has become a net source of carbon dioxide.
* 28 January: a study published in Environmental Research Letters reported that global mean sea surface temperature increases had more than quadrupled, from 0.06 K per decade during 1985–89 to 0.27 K per decade for 2019–23, and projected that the increase inferred over the past 40 years would likely be exceeded within the next 20 years.
* 3 February: a study co-authored by James Hansen published in Environment concluded that the IPCC had underestimated the effect of aerosols' planet-cooling radiative forcing, after enactment of international regulation of maritime aerosol emissions in the 2020s designed to improve air quality. This underestimation of aerosols' effect was said to cause underestimation of climate sensitivity, Hansen et al. writing that the reduction in aerosols explains the unexpectedly large global warming experienced in 2023-2024.
* 24 February: a study published by the non-profit Initiative on GHG Accounting of War estimated that the three years of the Russian invasion of Ukraine had caused 230 MtCO$_2$e (metric tons of carbon dioxide equivalent) emissions—citing warfare, buildings reconstruction, landscape fires, damage to energy infrastructure, refugee and civil aviation displacement.
* 7 March: a study by World Weather Attribution concluded that in a February 2025 heat wave, climate change made extreme heat at least 2 °C hotter and at least ten times more likely.

## Natural events and phenomena

* 1 January: a study published in Science Advances concluded that faster flow of the Antarctic Circumpolar Current (ACC) at higher latitudes causes upwelling of isotopically light deep waters around Antarctica, likely increasing atmospheric carbon dioxide levels and thereby potentially constituting a critical positive feedback for future warming.
* 6 January: a study published in Nature Climate Change stated that a fungal pathogen (Entomophaga maimaiga) that had successfully controlled the defoliation of the spongy moth in North American forests was becoming less effective due to climate change producing hotter, drier conditions. The study predicts this will lead to significantly decreased forest biodiversity and productivity by spongy moths, evidenced by recent increases in defoliation.
* 7 January: NOAA's Arctic Report Card 2024 reported that, including the impact of increased wildfires, the Arctic tundra region had shifted from storing carbon in the soil to becoming a carbon dioxide source, and that the Arctic remained a consistent source of methane—both adding to planet-warming greenhouse gases in the air.
* 8 January: a study published in Nature concluded that one-quarter of 23,496 decapod crustaceans, fishes and odonates studied, some of which provide climate change mitigation, are threatened with extinction. One-fifth of threatened freshwater species are affected by climate change and severe weather events.
* 9 January: a study published in Nature Reviews Earth & Environment estimated that since the mid-twentieth century, global-averaged 3-month and 12-month "hydroclimate whiplash" events have increased by 31–66% and 8–31%, respectively. Such increases amplify hazards associated with rapid swings between wet and dry states, including flash floods, wildfires, landslides and disease outbreaks. (Hydroclimate volatility refers to "sudden, large and/or frequent transitions between very dry and very wet conditions".)
* 15 January: a study published in Weather reported that the terrestrial biosphere's rate of natural carbon dioxide sequestration has fallen since its 2008 peak at a rate of 0.25% per year, a decline that will accelerate climate change.
* 21 January: a study published in the Proceedings of the National Academy of Sciences reported an "abrupt, coherent, climate-driven transformation" from "blue" (more transparent) to "brown" (less transparent) states of lakes in Greenland after a season of both record heat and rainfall drove a state change in these systems. This change was said to alter "numerous physical, chemical, and biological lake features", and the state changes were said to be unprecedented.
* February (reported): though polar bears and grizzly bears traditionally occupy distinct habitats (marine and land), arctic warming has forced polar bears inland into grizzly bear habitats, where the two species mate to produce hybrid "grolar bears" that have characteristics poorly adapted to either marine or land habitats.
* 26 February: a study published in Nature concluded that the Atlantic meridional overturning circulation (AMOC) is resilient to extreme greenhouse gas and North Atlantic freshwater forcings across 34 climate models, suggesting that an AMOC collapse is unlikely in the 21st century.
* 26 February: a study published in Science Advances concluded that short-, mid-, and long-term ambient outdoor heat can significantly accelerate epigenetic aging in older adults.
* 10 March: a study published in Nature Sustainability projected that climate change's cooling of the atmosphere occupied by space debris in low Earth orbit will reduce the atmosphere's drag on the debris, extending the debris' lifetime and potentially causing a 50–66% reduction in satellite carrying capacity at altitudes 200–1,000 km (120–620 mi).
* 4 February: a study published in Environmental Research Letters concluded that, in addition to the 2023 marine heat wave, an extensive river plume caused a ∼10–20 m (33–66 ft) thick strongly stratified barrier layer that contributed to Hurricane Idalia's rapid intensification (Category 1 to Category 4 in less than 24 hours).

## Actions, and goal statements
### Science and technology

* 12 February: a study published in Bird Study found that solar farms can benefit bird abundance and biodiversity in arable-dominated landscapes, especially when managed with biodiversity in mind.
* 3 March: advising policy makers to assimilate uncertainty into decision making to increase decarbonization, a study published in the Proceedings of the National Academy of Sciences (PNAS) urged a "portfolio approach" of planting diverse species of trees, as that approach "reduces exposure to downside cost extremes".

### Political, economic, legal, and cultural actions

* 20 January: within hours of his inauguration, U.S. President Donald Trump signed an executive order to withdraw the country from the 2015 Paris Agreement, joining only Iran, Libya and Yemen to become the only countries not party to the agreement.
* 4 March: the administration of U.S. president Donald Trump withdrew the country's representatives from the board of the United Nations' Loss and Damage Fund, which was formed to help poor and vulnerable nations cope with climate change-fueled disasters.
* 13 March: the Costa Rica-based Inter-American Court of Human Rights ordered the Ecuadorian government to protect Indigenous people from oil operations, to leave oil in the ground underneath their lands, and to ensure future oil operations do not impact Indigenous peoples living in voluntary isolation.

### Adaptation goal statements
## Consensus
## Projections

* 6 January: A study published in Scientific Reports comparing projected heat-related deaths from climate change with COVID-19 mortality rates across 38 global cities found that in half, annual heat-related deaths would likely exceed COVID-19 death rates within 10 years if global temperatures rise by 3.0 °C above pre-industrial levels. The study projected that cities in North America and Europe, particularly in Mediterranean and Central European regions, would have most dramatic increases in projected heat mortality.
* 3 February: climate risk financial modeling company First Street Foundation projected that by 2055, 70,026 U.S. neighborhoods (84% of all census tracts) may experience $1.47 trillion in net climate-related property value losses, citing insurance pressures and shifting consumer demand.
* 4 February: a review article published in Nature Reviews Earth & Environment, linking physical climate science with heat mortality risk, projected that human-caused global warming reaching 2 °C above preindustrial levels will cause tripling of global land area that is "uncompensable" (beyond which human core body temperature rises uncontrollably) for young adults.
* 26 February: a study published in Nature concluded that the Atlantic meridional overturning circulation (AMOC) is resilient to extreme greenhouse gas and North Atlantic freshwater forcings across 34 climate models, suggesting that an AMOC collapse is unlikely in the 21st century.
* 28 February: based on the Earth's orbital characteristics (precession, obliquity, and eccentricity), a study published in Science concluded that glacial-interglacial periodicity has been largely deterministic in a ~100,000 year cycle, and projected that in the absence of human-caused forcing, the next ice age would start in ~10,000 years.
* 5 March: a paper published in Nature cited the International Energy Agency as stating that data centers caused 1–1.3% of world electricity demand in 2022, but that, with electricity consumption expected to grow by more than 80% by 2050 owing to all sources, data centers were projected to "account for a relatively small share of overall electricity demand growth".
* 10 March: a study published in Nature Sustainability projected that climate change's cooling of the atmosphere occupied by space debris in low Earth orbit will reduce the atmosphere's drag on the debris, extending the debris' lifetime and potentially causing a 50–66% reduction in satellite carrying capacity at altitudes 200–1,000 km (120–620 mi).

## Significant publications

* Moon, Twila A.;Druckenmiller, Matthew L.;Thoman, Richard L., editors. "Arctic Report Card 2024" (PDF). National Oceanic and Atmospheric Administration (NOAA) Office of Oceanic and Atmospheric Research. doi:10.25923/b7c7-6431. Archived (PDF) from the original on 11 March 2025.