I'll gather the current scientific evidence to answer whether humans are driving climate change.
Yes, according to the overwhelming majority of climate science research, human activities are the dominant cause of the climate change observed since the mid-20th century.
Scientific consensus
•Major scientific agencies including NASA, NOAA, EPA, the World Meteorological Organization and national academies of science worldwide concur with this view.
•Multiple studies of the literature have found that 97% or more of climate experts agree on anthropogenic climate change as the primary driver of current warming.
•Yes, the vast majority of actively publishing climate scientists – 97 percent – agree that humans are causing global warming and climate change.
•Multiple methods — surveys of experts and massive literature reviews — converge on an overwhelming consensus that humans are the main cause of contemporary climate change: classic estimates cluster around 97%, recent multi-country studies and literature audits report agreement rates from ~97% to >99.9% depending on sampling.
What the IPCC and NASA conclude
•The United Nations' Intergovernmental Panel on Climate Change has concluded that there is a discernible human influence on the global climate. It is unequivocal that human influence has warmed the atmosphere, ocean and land.
•The fact that the IPCC has agreed — with the agreement of all 195 member countries — that it is unequivocal that human activity is causing climate change, is the strongest statement that the IPCC has ever made.
•In its most recent synthesis report, the SPM says with high confidence that human activities have "unequivocally caused global warming". This is the strongest wording to date about the role of human activities on observed warming from any IPCC assessment cycle.
•In its Sixth Assessment Report, the Intergovernmental Panel on Climate Change concluded that 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.
Evidence for human causation
•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.
•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.
Why natural factors alone do not explain current warming
•While the Sun has played a role in past climate changes, the evidence shows the current warming cannot be explained by the Sun.
•Since 1750, the average amount of energy from the Sun either remained constant or decreased slightly.
•If a more active Sun caused the warming, scientists would expect warmer temperatures in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere and a warming at the surface and lower parts of the atmosphere. That's because greenhouse gases are slowing heat loss from the lower atmosphere.
•Climate models that include solar irradiance changes can’t reproduce the observed temperature trend over the past century or more without including a rise in greenhouse gases.
•Natural processes are always influencing the earth’s climate and can explain climate changes prior to the Industrial Revolution in the 1700s, including changes in Earth’s orbit, variations in solar activity and volcanic activity. However, recent climate changes cannot be explained by natural causes alone.
In summary, natural climate variability exists, but the rapid warming, sea-level rise, and increase in climate extremes observed in recent decades are consistent with the physical effects of human-added greenhouse gases, and cannot be explained by natural forcings alone.