Are humans responsible for climate change?

Yes

Humans and climate change — I'll find the latest scientific consensus on our role.

Yes, according to the overwhelming scientific consensus, humans are responsible for the current climate change.

Scientific consensus

•Every major U.S. and international scientific academy, the IPCC, NASA and leading research organizations state that humans — primarily burning oil, gas and coal — are the dominant cause of recent warming.

•The IPCC report represents a clear scientific consensus that humans are responsible for climate change

> "Yes, the vast majority of actively publishing climate scientists – 97 percent – agree that humans are causing global warming and climate change"

NASA summarizes this as: “Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities.”

What the IPCC says

The UN Intergovernmental Panel on Climate Change (IPCC), which evaluates climate science on the basis of peer-reviewed literature, uses its strongest language in its Sixth Assessment Report (AR6, 2021):

> AR6 contains a chapter dedicated to assessing the human influence on the climate system, which opens with the statement: “It is unequivocal that human influence has warmed the global climate system since pre-industrial times”.

The authors conclude that it is “unequivocal” that humans have warmed the planet, causing “widespread and rapid” changes to Earth’s oceans, ice and land surface.

Specifically:

> According to the IPCC Sixth Assessment Report (AR6), human influence has warmed the planet by about 1.1 °C between 1850-1900 and 2011-2020, and it is unequivocal that this warming is human-caused.

The report states with high confidence:

> “Observed changes in the atmosphere, oceans, cryosphere and biosphere provide unequivocal evidence of a world that has warmed."

How scientists know it is not natural

Climate has changed naturally in the past due to orbital changes, solar variability, and volcanic activity, but scientists have identified two key differences for the current warming:

1.Rate of change: The first piece of evidence that the warming over the past few decades isn’t part of a natural cycle is how fast the change is happening

2.Natural factors ruled out: Over the past century, scientists from all over the world have been collecting data on natural factors that influence climate—things like changes in the Sun’s brightness, major volcanic eruptions, and cycles such as El Niño.

> Natural factors like solar activity and volcanic eruptions have actually had a slight cooling effect over the past 50 years. If only natural factors were at work, Earth would be cooling slightly, not warming rapidly.

Quantified attribution:

> Natural influences on temperature—El Niño, solar variability, and volcanic aerosols—have varied approximately plus and minus 0.2° C (0.4° F), (averaging to about zero), while human influences have contributed roughly 0.8° C (1° F) of warming since 1889.

Direct physical evidence

•Climate modelling predicts that human activities are causing the release of greenhouse gases and aerosols that are affecting Earth’s energy budget. Now, a NASA study has confirmed these predictions with direct observations for the first time: radiative forcings are increasing due to human actions

•NASA described it as: “It’s direct evidence that human activities are causing changes to Earth’s energy budget.”

The mechanism is the enhanced greenhouse effect: burning fossil fuels releases carbon dioxide, methane and other greenhouse gases that trap heat that would otherwise escape to space. Natural greenhouse effect keeps planet habitable, but human emissions have intensified it.

In short, while natural processes do affect climate, the rapid warming observed since the mid-20th century matches what is expected from human greenhouse gas emissions, and cannot be explained by natural factors alone.

Citations (1)

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In-depth Q&A: The IPCC’s sixth assessment report on climate science
Backs: “AR6 contains a chapter dedicated to assessing the human influence on the climate system, which opens with the statement: “It is unequivocal that human influence has warmed the global climate system since pre-industrial times”. The authors conclude that it is “unequivocal” that humans have warmed the planet, causing…”
evidence, article, points to yes. Claim: IPCC AR6 states it is unequivocal that human influence has warmed the climate system since pre-industrial times, causing widespread and rapid changes to oceans, ice and land.