Is climate change real?

Yes

Yes, climate change is real. The Earth’s climate is warming at an unprecedented rate in recent millennia, driven primarily by human activities, according to overwhelming scientific evidence and consensus.[1]

Scientific Consensus

Multiple independent studies of peer-reviewed literature and surveys of climate scientists show near-unanimous agreement:

•About 97% or more of actively publishing climate scientists conclude that human-caused climate change is happening. More recent analyses find greater than 99% consensus in the scientific literature that humans are the main cause.[2]

•Leading scientific organizations worldwide endorse this, including NASA, NOAA, the IPCC, the U.S. National Academy of Sciences, the American Association for the Advancement of Science (AAAS), the American Geophysical Union, the American Meteorological Society, and numerous national science academies.[2]

•The IPCC states it is “unequivocal” that human influence has warmed the atmosphere, ocean, and land, and that human activities are the principal driver of observed changes.[3]

There is no significant scientific debate among experts on the core facts of warming and its primary human cause, though research continues on details like regional impacts, tipping points, and precise future projections.

Key Evidence That the Climate Is Changing

Observations from multiple independent lines of evidence (thermometers, satellites, ice cores, ocean buoys, etc.) confirm warming and related changes:

•Global temperatures are rising: Earth’s average surface temperature has increased by about 1°C (roughly 1.8°F) or more since the late 19th century / pre-industrial period (around 1850–1900), with most warming in recent decades. Recent years (including 2023–2025) have been among the warmest on record.[1]

•Oceans are warming and acidifying: The ocean has absorbed most of the excess heat; the top layers have warmed significantly, and surface ocean acidity has increased by about 30% due to absorbed CO₂.[1]

•Ice is melting: 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 rapidly; Northern Hemisphere spring snow cover is decreasing.[1]

•Sea levels are rising: Global sea level has risen about 20 cm (8 inches) in the last century, with the rate nearly doubling in recent decades and continuing to accelerate.[1]

•Extremes are shifting: More frequent/intense heatwaves, heavy precipitation in many areas, and other changes consistent with a warmer climate.[1]

Paleoclimate records (ice cores, tree rings, sediments, corals) show the current rate of warming is roughly 10 times faster than the average post-ice-age warming, and CO₂ is rising ~250 times faster than natural rates after the last Ice Age.[1]

Human Cause

The primary driver is the enhanced greenhouse effect from rising atmospheric concentrations of CO₂, methane, and other greenhouse gases:

•Atmospheric CO₂ has risen from ~280 ppm pre-industrial to over 420 ppm recently (record highs, with large annual increases), far higher than levels in at least the last 800,000–2 million years. The isotopic signature and rapid rise confirm the source is largely fossil fuel burning (coal, oil, gas), plus deforestation and other human activities—not natural sources like volcanoes.[4]

•Basic physics (known since the 19th century) shows these gases trap heat. Observations confirm less infrared radiation escaping to space at relevant wavelengths, a planetary energy imbalance, and warming patterns (e.g., troposphere warming + stratosphere cooling) that match greenhouse gas forcing rather than natural factors like solar variability or volcanoes.[5]

•Climate models and detection/attribution studies show that natural factors alone cannot explain the observed warming; human greenhouse gas emissions account for essentially all of the long-term trend since the mid-20th century.[6]

Earth’s climate has always varied naturally (e.g., ice ages driven by orbital cycles), but the speed, magnitude, and global coherence of current changes, combined with the clear human fingerprint on greenhouse gases, distinguish this from past natural variability.[1]

In short, the evidence from direct measurements, paleoclimate data, physics, and attribution science is robust and multi-decadal. For primary sources, see NASA’s climate pages, NOAA Climate.gov, IPCC Assessment Reports, and the U.S. National Climate Assessment.

Citations (6)

1nasa.govGovernment
https://science.nasa.gov/climate-change/evidence/
Backs: “The Earth’s climate is warming at an unprecedented rate in recent millennia, driven primarily by human activities, according to overwhelming scientific evidence and consensus.”
evidence, article, points to yes. Claim: Earth's climate is warming at an unprecedented rate, driven by human activities, per overwhelming scientific evidence.
2nasa.govGovernment
https://science.nasa.gov/climate-change/scientific-consensus/
Backs: “More recent analyses find greater than 99% consensus in the scientific literature that humans are the main cause.”
statistic, article, points to yes. Claim: About 97% or more of actively publishing climate scientists agree human-caused climate change is happening; over 99% in recent literature analyses.
3climate.govGovernment
https://www.climate.gov/news-features/climate-qa/isnt-there-lot-disagreement-among-climate-scientists-about-global-warming
Backs: “The IPCC states it is “unequivocal” that human influence has warmed the atmosphere, ocean, and land, and that human activities are the principal driver of observed changes.”
attribution, article, points to yes. Claim: The IPCC states it is unequivocal that human influence has warmed the atmosphere, ocean, and land.
4climate.govGovernment
https://www.climate.gov/news-features/climate-qa/what-evidence-exists-earth-warming-and-humans-are-main-cause
Backs: “The isotopic signature and rapid rise confirm the source is largely fossil fuel burning (coal, oil, gas), plus deforestation and other human activities—not natural sources like volcanoes.”
evidence, article, points to yes. Claim: Atmospheric CO2 rose from ~280 ppm to over 420 ppm, with isotopic signature showing fossil fuel source.
5archive.mdData and tools
https://archive.md/2024.11.07-200429/https://www.climate.gov/news-features/climate-qa/what-evidence-exists-earth-warming-and-humans-are-main-cause
Backs: “Observations confirm less infrared radiation escaping to space at relevant wavelengths, a planetary energy imbalance, and warming patterns (e.g., troposphere warming + stratosphere cooling) that match greenhouse gas forcing rather than natural factors like solar variability or volcanoes.”
evidence, article, points to yes. Claim: Basic physics and observations show greenhouse gases trap heat, with warming patterns matching greenhouse forcing rather than natural factors.
6ncbi.nlm.nih.govAcademic
https://www.ncbi.nlm.nih.gov/books/NBK621795/
Backs: “Climate models and detection/attribution studies show that natural factors alone cannot explain the observed warming; human greenhouse gas emissions account for essentially all of the long-term trend since the mid-20th century.”
evidence, reference entry, points to yes. Claim: Detection and attribution studies show natural factors alone cannot explain observed warming; human emissions account for the long-term trend.