Are humans responsible for climate change?

Yes, the overwhelming scientific consensus is that human activities are the primary driver of climate change observed since the mid-20th century.

Key Evidence

Greenhouse gas emissions: Burning fossil fuels (coal, oil, and natural gas) releases carbon dioxide (CO₂) and other greenhouse gases into the atmosphere. These gases trap heat, creating an enhanced "greenhouse effect" that warms the planet. Atmospheric CO₂ levels have risen from about 280 parts per million (ppm) before the Industrial Revolution to over 420 ppm today—levels not seen in at least 800,000 years based on ice core data.

Scientific consensus: Major scientific bodies worldwide, including NASA, NOAA, the Intergovernmental Panel on Climate Change (IPCC), and national academies of science from virtually every country, agree that human activity is the dominant cause of observed warming since the mid-1900s. The IPCC's most recent assessments state it is "unequivocal" that human influence has warmed the atmosphere, ocean, and land.

Key human activities driving climate change:

Observable effects: Rising global average temperatures, melting glaciers and polar ice, rising sea levels, more frequent extreme weather events, and shifting precipitation patterns are all consistent with model predictions based on human-caused greenhouse gas increases.

Distinguishing from natural factors: Scientists have studied natural climate drivers—solar activity, volcanic eruptions, and natural climate cycles—and found that these alone cannot explain the rapid warming trend since the industrial era. The pace and pattern of recent warming align closely with the timeline of increased human greenhouse gas emissions.

While natural factors do influence climate to some degree, the current rate and scale of warming is understood to be predominantly driven by human activity, particularly since the mid-20th century.