Is climate change real?

Yes, climate change is real. It is supported by overwhelming scientific evidence and near-unanimous consensus among climate scientists. The Earth is warming at an unprecedented rate in recent millennia, primarily due to human activities, and this is causing widespread changes to the climate system.[1]

Scientific Consensus

Multiple independent studies of the peer-reviewed literature and surveys of climate scientists show extremely high agreement:

•Over 99% (and in some analyses >99.9%) of peer-reviewed scientific papers on climate agree that humans are the primary cause of recent warming. A 2021 survey of more than 88,000 climate-related studies found only a tiny handful of dissenting papers.[2]

•Earlier widely cited figures of ~97% consensus among actively publishing climate scientists have been reinforced and updated upward.[3]

•Leading scientific organizations worldwide—including NASA, NOAA, the IPCC, the American Association for the Advancement of Science, the American Geophysical Union, the National Academy of Sciences, and dozens of others—endorse this position. The IPCC states it is “unequivocal” that human influence has warmed the atmosphere, ocean, and land.[4]

There is no credible alternative scientific explanation that accounts for the observed changes.

Key Evidence

Multiple independent lines of evidence confirm warming and its human cause:

•Rising global temperatures: The planet’s average surface temperature has risen about 1.1°C (roughly 2°F) since the late 19th/pre-industrial period (1850–1900), with most warming in recent decades. Recent years (including 2023 and 2024) have been among the warmest on record. Each of the last several decades has been successively warmer.[5]

•Greenhouse gases: Atmospheric CO₂ has risen more than 50% since the Industrial Revolution (from ~280 ppm to over 410–420 ppm), primarily from burning fossil fuels. Ice cores and direct measurements show current levels and the rate of increase are unprecedented in at least the last 800,000 years. The isotopic fingerprint confirms the CO₂ is from fossil sources. Methane and other gases have also increased.[6]

•Oceans: The ocean has absorbed ~90% of the excess heat, with clear warming in the upper layers, rising ocean heat content, and increasing acidification (surface waters ~30% more acidic due to absorbed CO₂).[7]

•Cryosphere (ice): Greenland and Antarctic ice sheets are losing mass (hundreds of billions of tons per year), glaciers are retreating worldwide, Arctic sea ice extent and thickness have declined sharply, and Northern Hemisphere spring snow cover is decreasing.[7]

•Sea level: Global sea level has risen ~8–9 inches (20+ cm) since 1880, with the rate accelerating.[8]

•Extremes and impacts: Increases in heatwaves, heavy precipitation in many areas, droughts, and other extremes are observed and increasingly attributed to human-caused warming. Ecosystems and species are responding (e.g., range shifts).[4]

Paleoclimate records (ice cores, tree rings, sediments, etc.) show that the current rate of warming is much faster than natural changes after past ice ages. Natural factors (solar variability, volcanoes, orbital cycles) cannot explain the recent trend; solar output has been stable or slightly declining while temperatures rose, and the pattern (warming troposphere, cooling stratosphere) matches greenhouse forcing.[9]

Causes

The dominant cause is human emission of greenhouse gases (especially CO₂ from fossil fuels, plus methane, nitrous oxide, and land-use changes), which enhance the natural greenhouse effect and trap more heat. The IPCC and other assessments conclude human activities are responsible for essentially all the observed warming since the mid-20th century (best estimate ~1.07°C human-caused contribution matching the observed total).[10]

Climate has always varied naturally, but the current changes are distinct in speed, global coherence, and primary driver. Science continues to refine details (regional impacts, exact sensitivities, tipping points), but the core reality—that the climate is changing due to human influence—is established fact based on physics, observations, and models that successfully reproduce the record only when human forcings are included.

For primary sources, see NASA’s climate pages, NOAA Climate.gov, and the IPCC Sixth Assessment Report (AR6) Synthesis Report.

Citations (10)

1wikipedia.orgEncyclopedias and referencequality 0.83
https://en.wikipedia.org/wiki/Scientific_consensus_on_climate_change
Backs: “The Earth is warming at an unprecedented rate in recent millennia, primarily due to human activities, and this is causing widespread changes to the climate system.”
2cornell.eduAcademic
https://news.cornell.edu/stories/2021/10/more-999-studies-agree-humans-caused-climate-change
Backs: “A 2021 survey of more than 88,000 climate-related studies found only a tiny handful of dissenting papers.”
3nasa.govGovernment
https://science.nasa.gov/climate-change/scientific-consensus/?mod=article_inline
Backs: “Earlier widely cited figures of ~97% consensus among actively publishing climate scientists have been reinforced and updated upward.”
4ipcc.chGovernment
https://report.ipcc.ch/ar6syr/headline.html
Backs: “The IPCC states it is “unequivocal” that human influence has warmed the atmosphere, ocean, and land.”
5climate.govGovernment
https://climate.gov/news-features/understanding-climate/climate-change-global-temperature
Backs: “Each of the last several decades has been successively warmer.”
6archive.isData and tools
https://archive.is/2025.11.13-121149/https://science.nasa.gov/climate-change/evidence/
Backs: “The isotopic fingerprint confirms the CO₂ is from fossil sources. Methane and other gases have also increased.”
7nasa.govGovernment
https://science.nasa.gov/climate-change/evidence/
Backs: “The ocean has absorbed ~90% of the excess heat, with clear warming in the upper layers, rising ocean heat content, and increasing acidification (surface waters ~30% more acidic due to absorbed CO₂).”
8climate.govGovernment
https://www.climate.gov/climatedashboard
Backs: “Global sea level has risen ~8–9 inches (20+ cm) since 1880, with the rate accelerating.”
9archive.vnData and tools
https://archive.vn/2025.11.30-145549/https://science.nasa.gov/climate-change/causes/
Backs: “Natural factors (solar variability, volcanoes, orbital cycles) cannot explain the recent trend; solar output has been stable or slightly declining while temperatures rose, and the pattern (warming troposphere, cooling stratosphere) matches greenhouse forcing.”
10ipcc.chGovernment
https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-1/
Backs: “The IPCC and other assessments conclude human activities are responsible for essentially all the observed warming since the mid-20th century (best estimate ~1.07°C human-caused contribution matching the observed total).”