Are humans responsible for climate change?

Yes, humans are the primary cause of recent climate change (global warming since the Industrial Revolution). This is the unequivocal conclusion of the scientific community, based on multiple independent lines of evidence.[1]

Scientific Consensus

The Intergovernmental Panel on Climate Change (IPCC), in its Sixth Assessment Report (AR6, 2021), states: “It is unequivocal that human influence has warmed the atmosphere, ocean and land.” Observed increases in greenhouse gases (GHGs) like CO₂, methane, and nitrous oxide since around 1750 are unequivocally caused by human activities. The best estimate is that humans caused about 1.07°C of the roughly 1.1°C of global surface warming from 1850–1900 to 2010–2019, with natural drivers contributing negligibly (around –0.1°C to +0.1°C).[1]

Surveys of the peer-reviewed literature show greater than 99% consensus that humans are the main cause of modern climate change. A 2021 analysis of over 88,000 climate-related papers found the consensus exceeds 99%, updating earlier figures around 97%. Leading scientific organizations worldwide (NASA, NOAA, Royal Society, National Academies of Sciences, American Geophysical Union, and nearly 200 others) endorse this position.[2]

Key Lines of Evidence

Scientists attribute the warming through basic physics, observations, “fingerprinting” of patterns, and climate models:

Natural climate variability (El Niño, orbital cycles, solar variations, etc.) exists and always has, but it does not account for the long-term global trend since the mid-20th century or earlier. Human-caused warming is now detectable in most regions of the world.[6]

In short, the evidence is as robust as the link between smoking and cancer: multiple converging lines from physics, chemistry, observations, and modeling leave no credible alternative explanation for the bulk of recent warming. Continued emissions will drive further changes, with severity depending on the total amount emitted.