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Present-day global warming and its causes

IPCCWMO

This page delivers no verdict; it presents claims and evidence with their sources. No theory in science is absolute. Method

For everyone

According to the World Meteorological Organization, 2025 was about 1.43 °C warmer than pre-industrial times, and the 11 years 2015–2025 are the warmest on record. The UN's climate panel, the IPCC, stated in 2021 that it is "unequivocal" that this warming is caused by human activities. Some scientists argue that the role of natural factors such as the Sun and cosmic rays is underestimated, or that the climate's sensitivity to CO₂ is exaggerated.

For specialists

IPCC AR6 reported that the best estimate of human-caused warming for 2010–2019, about 1.07 °C, matches the whole of the observed warming. Solar irradiance measurements show no increase since the 1980s. The hypothesis that cosmic rays affect climate through cloud formation (Svensmark) showed an effect on nucleation in CERN's CLOUD experiment, but the effect was judged small for climate. Lindzen and Choi derived a low climate sensitivity (about 0.7 °C) from satellite data; the analysis was criticised methodologically by other researchers.

Claims

Evidence

Supporting

Measurement

2025 was about 1.43 °C warmer than pre-industrial; the last 11 years are the 11 warmest on record; greenhouse-gas concentrations and ocean heat content are at record levels.[2]

Statistics / meta-analysis

About 97% of more than 4,000 peer-reviewed paper abstracts expressing a position endorsed human-caused warming.[3]

Experiment

The CLOUD experiment at CERN showed that ionisation enhances particle nucleation but that its effect on cloud condensation nuclei is small.[7][8]

Challenging

Methodological critique

Criticisms of the classification method and sample of the 97% consensus study were published; the authors responded.[4][5]

Theoretical argument

It was proposed that cosmic rays play a significant, solar-activity-linked role in climate by affecting cloud formation.[6]

Measurement

Based on analysis of satellite radiation data, it was argued that climate sensitivity is much lower than mainstream estimates.[9]

Connections

Parent

Climate and climate change

Builds on

The greenhouse effect

Related

The Keeling curveEnergyBiodiversity loss and the "sixth mass extinction" debate

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Sources

  1. ReportIPCC (2021). Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report. Cambridge University Pressipcc.charchive
  2. ReportWorld Meteorological Organization (2026). State of the Global Climate 2025. WMO-No. 1391, Genevawmo.intarchive
  3. ArticleCook, J. et al. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters 8, 024024DOI 10.1088/1748-9326/8/2/024024archive
  4. ArticleTol, R. S. J. (2016). Comment on "Quantifying the consensus on anthropogenic global warming in the scientific literature". Environmental Research Letters 11, 048001DOI 10.1088/1748-9326/11/4/048001archive
  5. ArticleCook, J. et al. (2016). Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. Environmental Research Letters 11, 048002DOI 10.1088/1748-9326/11/4/048002archive
  6. ArticleSvensmark, H.; Friis-Christensen, E. (1997). Variation of cosmic ray flux and global cloud coverage — a missing link in solar-climate relationships. Journal of Atmospheric and Solar-Terrestrial Physics 59(11), 1225–1232DOI 10.1016/S1364-6826(97)00001-1archive
  7. ArticleKirkby, J. et al. (2011). Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation. Nature 476, 429–433DOI 10.1038/nature10343archive
  8. ArticlePierce, J. R.; Adams, P. J. (2009). Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates?. Geophysical Research Letters 36, L09820DOI 10.1029/2009GL037946archive
  9. ArticleLindzen, R. S.; Choi, Y.-S. (2011). On the observational determination of climate sensitivity and its implications. Asia-Pacific Journal of Atmospheric Sciences 47, 377–390DOI 10.1007/s13143-011-0023-xarchive

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Cite this page

APA

Athena contributors. (2026). Present-day global warming and its causes. Athena: The tree of human knowledge. Retrieved November 1, 2026, from https://latifkedi.github.io/athena/en/d/kuresel-isinma/

BibTeX
@misc{athena_kuresel_isinma,
  title        = {Present-day global warming and its causes},
  author       = {{Athena contributors}},
  year         = {2026},
  howpublished = {\url{https://latifkedi.github.io/athena/en/d/kuresel-isinma/}},
  note         = {Athena: The tree of human knowledge. Accessed: 2026-11-01}
}

Added: September 27, 2026 · Last changed: September 28, 2026 · Page history

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