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 a summary of why scientists reach this conclusion:

Key Evidence

Greenhouse gas emissions
Burning fossil fuels (coal, oil, and natural gas) releases carbon dioxide (CO₂) and other greenhouse gases into the atmosphere. These gases trap heat, creating an enhanced greenhouse effect. CO₂ concentrations have risen from about 280 parts per million (ppm) in pre-industrial times to over 420 ppm today—levels not seen in at least 800,000 years based on ice core data.

Other human activities

Scientific consensus
Major scientific organizations worldwide—including NASA, NOAA, the IPCC (Intergovernmental Panel on Climate Change), and national academies of science from numerous countries—agree that human activities are extremely likely (>95% probability) to be the dominant cause of observed warming since the mid-20th century.

Attribution methods
Scientists use climate models to compare observed warming patterns against natural factors alone (like solar variation and volcanic activity) versus natural factors plus human influences. The models only match observed warming when human factors are included, providing strong evidence for human causation.

Rate of change
While Earth's climate has changed naturally throughout its history, the current rate of warming—about 1.1°C since pre-industrial times, occurring over roughly 150 years—is much faster than natural climate shifts, which typically occur over thousands of years.

If you're interested in more specific aspects (like current data, regional impacts, or particular mitigation strategies), I can look into more recent information for you.