Are humans responsible for climate change?

Yes, the overwhelming scientific consensus is that human activities are the primary driver of climate change observed since the mid-20th century. Here's why:

Key Evidence

Greenhouse gas emissions: Burning fossil fuels (coal, oil, and natural gas) for energy, along with deforestation, agriculture, and industrial processes, has dramatically increased atmospheric concentrations of carbon dioxide (CO₂), methane (CH₄), and other greenhouse gases. CO₂ levels have risen from about 280 parts per million in pre-industrial times to over 420 ppm today—levels unprecedented in at least 800,000 years based on ice core data.

The greenhouse effect: These gases trap heat in the atmosphere that would otherwise radiate back into space, causing global average temperatures to rise. Global surface temperatures have increased roughly 1.1-1.2°C above pre-industrial levels, with most of that warming occurring since 1975.

Scientific consensus: Major scientific bodies worldwide—including NASA, NOAA, the National Academies of Science, and virtually every national science academy—agree on this. The Intergovernmental Panel on Climate Change (IPCC), which synthesizes thousands of peer-reviewed studies, has stated with high confidence that human influence is the dominant cause of observed warming since the 1950s.

Multiple lines of evidence support this conclusion:

What This Means

While Earth's climate has changed naturally throughout history due to factors like volcanic activity, solar cycles, and orbital variations, the current rate and pattern of warming cannot be explained by natural causes alone. The scientific evidence strongly indicates that human-caused greenhouse gas emissions are the dominant driver of the warming observed over the past century, particularly since the mid-20th century.

If you'd like, I can search for the most current data on this topic, such as recent temperature records or the latest IPCC findings.