Are humans responsible for climate change?

I'll gather the current science to answer whether humans are responsible for climate change.

Yes — According to the overwhelming scientific evidence and consensus, humans are responsible for modern climate change.

> There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.

What the science says

> "It is unequivocal that human influence has warmed the atmosphere, ocean and land,"

> Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming, with global surface temperature reaching 1.1°C above 1850–1900 in 2011–2020.

The IPCC also states:

> "It is unequivocal that the increase of CO2, methane, and nitrous oxide in the atmosphere over the industrial era is the result of human activities and that human influence is the principal driver of many changes observed across the atmosphere, ocean, cryosphere, and biosphere."

And:

> Observed increases in well-mixed GHG concentrations since around 1750 are unequivocally caused by GHG emissions from human activities.

> "Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact."

Formal detection and attribution studies show that the best estimate is that all the warming observed between 1850-1900 and 2010-2019 is caused by humans.

> multiple studies published in peer-reviewed scientific journals show that climate-warming trends over the past century are extremely likely due to human activities.

The IPCC Fifth Assessment Report found there is 95 percent certainty that humans have caused most of the warming of the planet's surface that has occurred since the 1950s.

Leading scientific organizations have endorsed this. For example:

> Based on extensive scientific evidence, it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century.

Scientific Consensus

Nearly all actively publishing climate scientists agree humans are causing climate change. Quantitative studies find:

Is there any natural climate change?

Yes, climate has changed naturally in the past due to factors like volcanic eruptions, changes in solar output, and Earth's orbital cycles. However, scientists have measured those natural drivers and found they cannot explain the rapid warming observed since the mid-20th century. Natural drivers changed global surface temperature by only ±0.1°C, and internal variability by ±0.2°C, while human-caused warming is estimated at 0.8°C to 1.3°C with a best estimate of 1.07°C. Human greenhouse gas emissions dominate the warming, partly masked by cooling from human-produced aerosols.

In summary, while natural variability exists, the current, rapid warming of the atmosphere, ocean and land is unequivocally caused by humans, primarily through the burning of fossil fuels (coal, oil, and gas) and land-use change that increases greenhouse gas concentrations.