Are humans responsible for climate change?

Your question touches the scientific consensus on climate — I'll pull the latest evidence to give you a clear answer.

Yes — according to the overwhelming scientific consensus and evidence assessed by leading scientific agencies, 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." NASA also states "Human activities are driving the global warming trend observed since the mid-20th century."

•Using the scientific method, "scientists have shown that humans are extremely likely the dominant cause of today’s climate change." The NASA evidence page notes the influence of human activity on warming has evolved from theory to established fact since systematic scientific assessments began in the 1970s

•The Intergovernmental Panel on Climate Change (IPCC) concludes: "Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming"

•The IPCC Fifth Assessment Report (2013-2014) concluded it is "95% certain that human activities, primarily the emission of greenhouse gases, are the dominant cause of global warming since the mid-20th century." More generally the IPCC, USGCRP assessments indicate "it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-twentieth century."

•Humans emissions and activities have "caused around 100% of the warming observed since 1950, according to the Intergovernmental Panel on Climate Change’s (IPCC) fifth assessment report."

Mechanism is the human enhancement of the greenhouse effect:

> "Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2) [...] To a lesser extent, the clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases."

This consensus is very strong among experts:

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

•"Multiple studies published in peer-reviewed scientific journals show that 97 percent or more of actively publishing climate scientists agree: Climate-warming trends over the past century are extremely likely due to human activities."

•Scientific consensus identifying humans as primarily responsible "was already forming in the 1980s. Today, 97 percent to 99.9 percent of climate scientists agree that climate change is happening and that human activity is the primary cause."

Natural climate variability and factors like solar changes have caused climate changes in the past, but NASA and the IPCC find they cannot explain the rapid warming observed since the mid-20th century without accounting for human-caused greenhouse gas emissions.

Citations (2)

1nasa.govGovernment
Climate Change - NASA Science
Backs: “Yes — according to the overwhelming scientific consensus and evidence assessed by leading scientific agencies, humans are responsible for modern climate change. There is "unequivocal evidence that Earth is warming at an unprecedented rate.”
2nasa.govGovernment
The scientific method and climate change: How scientists know
Backs: “Human activity is the principal cause." NASA also states "Human activities are driving the global warming trend observed since the mid-20th century.". Using the scientific method, "scientists have shown that humans are extremely likely the dominant cause of today’s climate change." The NASA evidence page notes the…”