Are humans responsible for climate change?

Are we driving climate change? I'll gather the latest scientific evidence to answer.

Yes - humans are the principal cause of the current climate change, according to the overwhelming scientific evidence and consensus.

What the science says

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

> Scientific evidence continues to show that human activities (primarily the human burning of fossil fuels) have warmed Earth’s surface and its ocean basins

NASA explains:
> Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the "greenhouse effect" — warming that results when the atmosphere traps heat radiating from Earth toward space.

> The greenhouse effect is essential to life on Earth, but human-made emissions in the atmosphere are trapping and slowing heat loss to space.

> Human Activity Is the Cause of Increased Greenhouse Gas Concentrations

> Over the last century, burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2).

> The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels by nearly 50% since 1750

> This increase is due to human activities, because scientists can see a distinctive isotopic fingerprint in the atmosphere.

In its Sixth Assessment Report (AR6), the Intergovernmental Panel on Climate Change (IPCC) concluded:
> 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.

Other IPCC statements summarized:

> The report by the Intergovernmental Panel on Climate Change (IPCC) says there is 95 percent certainty that humans have caused most of the warming of the planet's surface that has occurred since the 1950s

> 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.

> it is extremely likely (95-100% probability) that most of the warming since 1950 has been due to human influence.

Direct observational proof has also been obtained:

> 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

Scientific consensus

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

> Nearly all actively publishing climate scientists (97–100%) say humans are causing climate change.

> A 2019 review of scientific papers found the consensus on the cause of climate change to be at 100%, and a 2021 study concluded that over 99% of scientific papers agree on the human cause of climate change.

Why natural causes cannot explain current warming

Climate does change naturally due to solar variability, volcanic eruptions, and internal variability, but:

> The likely contributions of natural forcing and internal variability to global temperature change over that period are minor

> The likely range of the human contribution to the global mean temperature increase over the period 1951–2010 is 1.1° ... This translates to a likely human contribution of 93%–123% of the observed 1951–2010 change.

> the combined influence of volcanoes and changes in solar activity would have resulted in cooling rather than warming over the past 50 years.

> Since 1750, the average amount of energy from the Sun either remained constant or decreased slightly

NASA notes that if the Sun were causing warming, all layers of the atmosphere would warm, but observations show cooling in the upper atmosphere and warming at the surface — consistent with greenhouse gases trapping heat in the lower atmosphere.

In short: Natural factors explain some past climate changes, but the rapid warming since the mid-20th century — about 1.1°C since the late 1800s — is dominated by human emissions of CO2, methane, nitrous oxide and other greenhouse gases from burning fossil fuels, deforestation, agriculture and industrial processes.