Is climate change real?

Yes, climate change is real. The Earth is warming at an unprecedented rate in recent geological history, and human activities—primarily the emission of greenhouse gases like carbon dioxide (CO₂) from burning fossil fuels—are the principal cause. This is established scientific fact, supported by overwhelming evidence from multiple independent lines of observation and affirmed by virtually the entire climate science community.[1]

Scientific Consensus

Multiple comprehensive reviews of the peer-reviewed literature show extremely high agreement:

•Over 99% (and in some analyses >99.9%) of climate scientists and relevant scientific papers agree that humans are the main cause of recent global warming.[2]

•Leading organizations worldwide, including NASA, the Intergovernmental Panel on Climate Change (IPCC), the U.S. National Academy of Sciences, the American Association for the Advancement of Science, the American Geophysical Union, and nearly 200 other scientific bodies, endorse this position.[3]

•The IPCC’s Sixth Assessment Report (AR6) 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 across the climate system. Global surface temperature reached about 1.1°C above 1850–1900 levels in 2011–2020.[4]

The consensus has strengthened over time as data and attribution studies (which distinguish human “fingerprints” from natural variability) have improved.

Key Evidence

Observations from satellites, ground stations, ocean buoys, ice cores, tree rings, and other sources all point to the same conclusion:

•Rising global temperatures: The planet’s average surface temperature has risen about 1°C (roughly 2°F) since the late 19th century, with most warming in the past 40+ years. Recent years have repeatedly set records as the warmest.[1]

•Ocean warming and acidification: The oceans have absorbed most of the excess heat (about 90%) and a significant portion of emitted CO₂, leading to warming of the upper ocean and increased acidity (about 30% since the Industrial Revolution).[1]

•Melting ice and rising seas: 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 are declining, Northern Hemisphere spring snow cover is decreasing, and global sea level has risen about 20 cm (8 inches) in the last century (with the rate accelerating).[1]

•Extreme events: Increases in heatwaves, heavy precipitation, and other extremes are being observed and attributed in part to human-caused warming.[1]

•Atmospheric composition: CO₂ levels have risen dramatically since the Industrial Revolution (from ~280 ppm to over 420 ppm), far faster than natural changes, with a clear isotopic signature of fossil fuel origin. The greenhouse effect of these gases is well-understood physics dating back to the 19th century.[1]

Natural factors (solar variability, volcanic activity, orbital cycles) cannot explain the observed warming pattern. For example, the lower atmosphere is warming while the upper atmosphere cools—a signature of greenhouse gas forcing, not increased solar output. The current rate of change is roughly 10 times faster than typical post-ice-age warming.[5]

Causes and Context

Earth’s climate has always varied naturally, but the rapid warming since the mid-20th century (and especially recently) matches the rise in human greenhouse gas emissions and is inconsistent with natural drivers alone. The IPCC and others conclude human influence is the dominant cause.[4]

Continued emissions will drive further warming, with impacts already widespread (on weather extremes, ecosystems, sea levels, human health, and more) and projected to intensify. Limiting warming requires rapid reductions in greenhouse gas emissions toward net-zero CO₂.[4]

In short, the evidence is robust, multi-decadal, multi-method, and continually reinforced by new data. Climate change is not a matter of opinion or debate within the scientific community studying it—it is an observed reality driven primarily by human activity. For primary sources, see NASA’s climate pages and the IPCC AR6 reports.

Citations (5)

1nasa.govGovernment
https://science.nasa.gov/climate-change/evidence/
Backs: “This is established scientific fact, supported by overwhelming evidence from multiple independent lines of observation and affirmed by virtually the entire climate science community.”
2cornell.eduAcademic
https://news.cornell.edu/stories/2021/10/more-999-studies-agree-humans-caused-climate-change
Backs: “Over 99% (and in some analyses >99.9%) of climate scientists and relevant scientific papers agree that humans are the main cause of recent global warming.”
3nasa.govGovernment
https://science.nasa.gov/climate-change/scientific-consensus/?mod=article_inline
Backs: “National Academy of Sciences, the American Association for the Advancement of Science, the American Geophysical Union, and nearly 200 other scientific bodies, endorse this position.”
4ipcc.chGovernment
https://report.ipcc.ch/ar6syr/headline.html
Backs: “Global surface temperature reached about 1.1°C above 1850–1900 levels in 2011–2020.”
5nasa.govGovernment
https://science.nasa.gov/climate-change/causes/
Backs: “The current rate of change is roughly 10 times faster than typical post-ice-age warming.”