Yes. Humans are the dominant cause of the observed global warming and related climate changes since the mid-20th century.
The Evidence
•Greenhouse gas increase: Atmospheric CO₂ has risen from ~280 ppm pre-industrial to over 420 ppm today, primarily from burning fossil fuels (coal, oil, gas), cement production, and land-use changes (deforestation). Isotopic signatures (¹⁴C and ¹³C ratios) confirm the excess carbon is from fossil sources, not volcanoes or oceans. Methane and nitrous oxide have also risen sharply due to agriculture, fossil fuels, and waste.
•Physics of radiative forcing: These gases trap outgoing longwave radiation. The resulting energy imbalance is measured directly by satellites and ocean heat content. The greenhouse effect is basic, repeatedly verified physics—not a hypothesis.
•Attribution studies: Climate models that include only natural drivers (solar variability, volcanic aerosols, orbital cycles) cannot reproduce the rapid warming since ~1950, the stratospheric cooling, the tropospheric warming pattern, or the ocean heat uptake. Models that include anthropogenic forcings match observations closely. Detection-and-attribution work (IPCC AR6 and earlier) quantifies human influence as the principal driver, with best estimates around 100% of the observed warming (natural factors net near zero or slightly cooling in recent decades).
•Multiple lines of evidence: Retreat of glaciers and ice sheets, rising sea levels (thermal expansion + melt), shifting seasons/phenology, ocean acidification (from CO₂ dissolution), and extreme heat trends all align with the expected fingerprint of greenhouse forcing rather than solar or internal variability.
Scientific Consensus
The Intergovernmental Panel on Climate Change (IPCC), national academies of science (US, UK, China, etc.), NASA, NOAA, and virtually every major scientific body state that human activities are the main cause. Statements of this consensus appear in assessment reports synthesizing thousands of peer-reviewed studies. Claims of major natural dominance or “it’s just cycles” fail when tested against the data (e.g., solar irradiance has been flat-to-declining while temperatures rose; the current rate far exceeds typical Holocene variability).
Natural climate variability (ENSO, AMO, volcanic eruptions, orbital changes) still occurs and modulates year-to-year or decade-to-decade weather, but it does not explain the long-term trend. Feedbacks (water vapor, ice-albedo, clouds) amplify the initial human forcing.
For primary sources, see IPCC AR6 Working Group I (2021), NASA’s climate pages, and the instrumental + paleoclimate records.