Are humans responsible for climate change?

Yes, humans are the primary cause of the rapid climate change (global warming) observed since the Industrial Revolution, particularly since the mid-20th century. This is the unequivocal conclusion of the global scientific community, based on multiple independent lines of evidence.[1]

Scientific Consensus

How Humans Cause It

Human activities have greatly increased atmospheric concentrations of heat-trapping GHGs:

These GHGs enhance the natural greenhouse effect, trapping more outgoing infrared radiation. Basic physics (known since the 19th century) predicts warming from rising CO₂; observations confirm it.[5]

Evidence and Attribution

Multiple lines of evidence rule out natural causes as the main driver of recent warming and attribute it to humans (“detection and attribution” science):

Natural variability (e.g., El Niño) and factors like the Sun or volcanoes influence short-term fluctuations but contribute negligibly (±0.1°C or less) to the long-term global trend.[1]

Context and Nuance

Earth’s climate has always changed naturally, but the current rapid warming—and its suite of associated changes—is overwhelmingly anthropogenic. The IPCC and others note that every additional ton of GHGs increases future warming and risks. While uncertainties remain in exact regional projections, sensitivity, or some feedbacks, the core attribution of recent global warming to humans is settled science at the highest confidence levels (“unequivocal,” “virtually certain” for many aspects).

In short, the evidence from physics, observations, models, isotopes, and paleoclimate records converges on the same answer: human activities, mainly fossil fuel combustion and land-use change, are responsible.