Humans and climate change — I'll pull the latest scientific consensus on our role.
Yes - according to the overwhelming scientific evidence, humans are responsible for the rapid climate change observed since the mid-20th century, primarily through greenhouse gas emissions.
What the scientific consensus says
•There is scientific consensus that the Earth has been consistently warming since the start of the Industrial Revolution, and that this warming is mainly the result of a rapid increase in atmospheric carbon dioxide (CO2) caused by human activities.
•Nearly all actively publishing climate scientists say humans are causing climate change.
•Multiple studies published in peer-reviewed scientific journals show that climate-warming trends over the past century are extremely likely due to human activities.
Quantitative reviews of the literature consistently find very high agreement:
•widely cited surveys and institutional summaries cite ~97% agreement among actively publishing climate scientists that humans are causing warming
•a 2021 literature survey of 88,125 climate-related papers reported greater than 99% agreement in the peer-reviewed literature
•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
Major scientific organizations explicitly endorse this position:
•"Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver." (2009, Statement from 18 Scientific Associations)
•American Geophysical Union: "Based on extensive scientific evidence, it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century."
•U.S. Global Change Research Program (13 U.S. government departments and agencies): "Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities."
Why scientists attribute recent warming to humans
1. Human activity is the principal cause of recent warming.
•There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.
•Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the "greenhouse effect".
•Scientific evidence continues to show that human activities (primarily the human burning of fossil fuels) have warmed Earth’s surface and its ocean basins.
•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 current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia.
2. The Intergovernmental Panel on Climate Change (IPCC) assessment:
•“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."
•“Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact.”
•The Fifth Assessment Report (AR5) concluded that 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.
•In its 2013 fifth assessment report, the IPCC stated it is “extremely likely that more than half of the observed increase in global average surface temperature” from 1951 to 2010 was caused by human activity.
•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.
•The IPCC states: “It is unequivocal that human influence has warmed the atmosphere, ocean and land since pre-industrial times.”
•Human activities have increased concentrations of well-mixed greenhouse gases since around 1750. The IPCC assesses those observed increases as unequivocally caused by human activities.
The IPCC's quantitative attribution illustrates this:
> The observed long-term global warming is primarily human-caused. Natural variability explains many year-to-year changes but is far too small to account for the sustained rise since the pre-industrial period.
Multiple lines of evidence show that greenhouse gas emissions from human activities are the primary drivers of the observed long-term warming trend and that natural forces cannot account for observed changes.
3. Natural vs. human causes:
Climate has changed naturally in the past due to factors that can contribute to climate change including the sun’s intensity, volcanic eruptions, and changes in naturally occurring greenhouse gas concentrations.
However:
•Humans—more specifically, the greenhouse gas (GHG) emissions that human activity generates—are the leading cause of the earth’s rapidly changing climate today.
•Natural factors like changes in the sun and volcanic eruptions have recognizable timing and patterns, but their combined contribution to recent multi-decadal global warming is small compared to human influence.
In short, while natural processes do affect climate, the rapid warming of the last ~150 years, and especially since 1950, cannot be explained by solar, volcanic, or orbital changes alone, and is reproduced only when human greenhouse-gas emissions are included in climate models.