Are we responsible for climate change? I'll gather the latest scientific consensus on humanity's role.
According to the overwhelming scientific consensus, humans are responsible for modern climate change:
•Scientific consensus identifying humans as primarily responsible for climate change was already forming in the 1980s, and Today, 97 percent to 99.9 percent of climate scientists agree that climate change is happening and that human activity is the primary cause.
•Other analyses put agreement that humans are causing recent warming at roughly 97% or higher, with some large-scale literature reviews reporting consensus estimates above 99%.
•The Intergovernmental Panel on Climate Change (IPCC) stated that, "It is unequivocal that human influence has warmed the atmosphere, ocean and land… climate change is already affecting many weather and climate extremes in every region across the globe."
•The IPCC also concluded it is "extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."
•An earlier IPCC assessment said there is at least 95% certainty that human activities are the principal cause.
•NASA states: There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.
•NASA also states that today, we have a clear understanding that our climate is changing rapidly, and that human activities are responsible for the vast majority of that change
•Synthesized science agencies state: "Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming"
The evidence for human causation vs. natural causes:
•Multiple lines of evidence show that greenhouse gas emissions from human activities are the primary driver of the observed long-term warming trend. No known natural drivers, such as incoming solar radiation or volcanic emissions, can explain observed changes.
•While there are natural factors that affect the Earth's climate, the combined influence of volcanoes and changes in solar activity would have resulted in cooling rather than warming over the past 50 years.
•Humans emissions and activities have caused around 100% of the warming observed since 1950, according to the IPCC's fifth assessment report.
Natural climate variability is real and climate has changed in the past due to orbital changes, solar activity and volcanism. What makes current warming different is the rate, the scale, and that it matches what is expected from greenhouse gas emissions and cannot be explained by natural factors alone.
In summary, science concludes humans - principally through burning fossil fuels, deforestation and industrial processes that increase greenhouse gases like carbon dioxide and methane - are the dominant cause of observed warming since the mid-20th century.