Is climate change real?

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

Evidence That the Climate Is Warming

Multiple independent lines of evidence confirm planetary-scale warming:

•Global temperatures: Earth’s average surface temperature has risen by about 1.1–1.3°C (roughly 2°F) since the late 19th century/pre-industrial period (1850–1900), with most warming in the past few decades. Recent years (including 2023 and 2024) have been among the warmest on record. The past decade includes the hottest years in the instrumental record.[1]

•Oceans: The oceans have absorbed ~90% of the excess heat, with the top layers warming significantly and ocean heat content at record highs. This contributes to sea level rise (about 8–9 inches/20–24 cm since 1880, accelerating recently) via thermal expansion and melting ice.[1]

•Cryosphere (ice and snow): 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]

•Other indicators: Rising atmospheric CO₂ (from ~280 ppm pre-industrial to over 410–420 ppm recently), ocean acidification (~30% increase in acidity), shifts in species ranges, earlier plant blooming/migrations, and increases in certain extremes (more frequent/intense heatwaves, heavy precipitation in many areas).[2]

Paleoclimate data (ice cores, tree rings, sediments, corals) show the current rate of warming and CO₂ rise is much faster than natural changes after ice ages (CO₂ increase ~250 times faster than natural post-Ice Age rates).[1]

Primary Cause: Human Activities

The warming is largely caused by human emissions of greenhouse gases (especially CO₂ from burning fossil fuels, plus methane and nitrous oxide), which enhance the natural greenhouse effect by trapping heat.[3]

•Basic physics of greenhouse gases has been understood since the 19th century.

•Isotopic fingerprints confirm the extra CO₂ comes from fossil fuels.

•Climate models and “fingerprinting” match observed patterns (e.g., tropospheric warming + stratospheric cooling) to human influences far better than natural factors alone (solar variations, volcanoes, internal variability). Solar output has not increased net over recent decades.[2]

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

Natural climate variability exists and has caused past changes (e.g., orbital cycles for ice ages), but it cannot explain the rapid modern warming.

Scientific Consensus

There is near-unanimous agreement among climate scientists and major scientific organizations:

•Studies of peer-reviewed literature find >97% to >99.9% consensus that humans are the main cause of recent warming (e.g., analyses of tens of thousands of papers).[4]

•Endorsements come from NASA, NOAA, the IPCC, U.S. National Academy of Sciences, Royal Society, American Geophysical Union, American Meteorological Society, AAAS, and nearly 200 scientific organizations worldwide. No major scientific body with relevant expertise dissents on the basics.[5]

The IPCC’s assessments (based on thousands of scientists reviewing the literature) have strengthened over time: warming is “unequivocal,” and human causation is an “established fact.”[3]

Context and Uncertainties

Climate has always changed, but the current speed and human driver make it concerning for ecosystems, societies, sea levels, extremes, and more. Some details (exact regional impacts, cloud feedbacks, tipping point timings) involve ongoing research and ranges of projections, but the core facts—warming is happening and is mostly human-caused—are robust.[2]

In short, the evidence from direct measurements, satellites, paleoclimate records, physics, and independent scientific bodies is clear and consistent: climate change is real and primarily human-driven. For primary sources, see NASA’s climate pages, IPCC reports, NOAA, and the Royal Society/National Academy of Sciences summaries.

Citations (5)

1nasa.govGovernment
https://science.nasa.gov/climate-change/evidence/
Backs: “Earth’s climate is warming at an unprecedented rate in recent millennia, driven primarily by human activities, according to overwhelming evidence from observations, physics, and scientific assessments.”
2royalsociety.orgAcademic
https://royalsociety.org/news-resources/projects/climate-change-evidence-causes/
Backs: “Rising atmospheric CO₂ (from ~280 ppm pre-industrial to over 410–420 ppm recently), ocean acidification (~30% increase in acidity), shifts in species ranges, earlier plant blooming/migrations, and increases in certain extremes (more frequent/intense heatwaves, heavy precipitation in many areas).”
3ipcc.chGovernment
https://report.ipcc.ch/ar6syr/headline.html
Backs: “The warming is largely caused by human emissions of greenhouse gases (especially CO₂ from burning fossil fuels, plus methane and nitrous oxide), which enhance the natural greenhouse effect by trapping heat.”
4cornell.eduAcademic
https://news.cornell.edu/stories/2021/10/more-999-studies-agree-humans-caused-climate-change
Backs: “Studies of peer-reviewed literature find >97% to >99.9% consensus that humans are the main cause of recent warming (e.g., analyses of tens of thousands of papers).”
5nasa.govGovernment
https://science.nasa.gov/climate-change/scientific-consensus/?mod=article_inline
Backs: “No major scientific body with relevant expertise dissents on the basics.”