Are humans responsible for climate change?

Yes, humans are the primary cause of the observed climate change (global warming) since the Industrial Revolution, particularly the rapid warming since the mid-20th century. This is the overwhelming scientific consensus, described as "unequivocal" by the Intergovernmental Panel on Climate Change (IPCC).[1]

Scientific Consensus

Key Evidence

Multiple independent lines of evidence converge on human responsibility:

Natural Variability Exists but Does Not Explain Recent Change

Earth’s climate has always varied due to orbital cycles (Milankovitch), solar output, volcanoes, and internal oscillations (e.g., El Niño). These continue to operate and cause year-to-year or decadal fluctuations. However, they do not account for the long-term trend since the mid-20th century or the magnitude of observed changes. Solar output has been relatively stable or slightly declining in recent decades while temperatures rose.[4]

NASA, NOAA, and other agencies summarize: Human activities—primarily burning fossil fuels (coal, oil, gas), deforestation, and industrial processes—are the principal driver.[6]

In short, the evidence from observations, physics, paleoclimate data, isotopic analysis, and modeling is robust and multi-faceted. The scientific community regards human responsibility for recent climate change as settled fact, comparable to other well-established scientific conclusions. Uncertainties remain about exact future projections, regional impacts, and climate sensitivity details, but not about the primary cause of the warming observed so far.