Your question touches the core of climate science — I'll gather the latest evidence on human responsibility.
Yes - according to the overwhelming scientific evidence, modern climate change is primarily caused by humans, although Earth's climate has also changed naturally in the past.
What the science says
Multiple independent analyses and expert surveys conclude humans are the main cause of recent warming.
•Multiple independent analyses of the peer-reviewed literature and surveys of climate experts put agreement that humans are causing recent warming at roughly 97% or higher
•Today, 97 percent to 99.9 percent of climate scientists agree that climate change is happening and that human activity is the primary cause
•Nearly all actively publishing climate scientists say humans are causing climate change
Leading scientific organizations have issued similar statements:
•"Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth's climate, primarily through greenhouse gas emissions."
•"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. There is no alterative explanation supported by convincing evidence."
•"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)
IPCC assessment - "unequivocal"
The Intergovernmental Panel on Climate Change (IPCC), which synthesizes research from hundreds of scientists and is approved by 195 member countries, uses its strongest language:
•"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."
•"It is unequivocal that human influence has warmed the global climate system since pre-industrial times"
•"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 IPCC noted: "The fact that the IPCC has agreed — with the agreement of all 195 member countries — that it is unequivocal that human activity is causing climate change, is the strongest statement that the IPCC has ever made."
Other agency syntheses state: "Human activities, principally through emissions of greenhouse gases, have unequivocally caused global warming"
How humans are causing it
Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the "greenhouse effect" — warming that results when the atmosphere traps heat radiating from Earth toward space
Human activities are primarily responsible, particularly the burning of fossil fuels, deforestation, and urbanization, which increase greenhouse gases in the atmosphere
Specific mechanisms:
• Burning fossil fuels: Over the last century, burning of fossil fuels like coal and oil has increased the concentration of atmospheric carbon dioxide (CO2) The industrial activities that our modern civilization depends upon have raised atmospheric carbon dioxide levels by nearly 50% since 1750, and scientists can see a distinctive isotopic fingerprint showing this increase is due to human activities.
•Deforestation and land use: Clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases
•Other greenhouse gases: Methane from livestock, landfills, rice farming and fossil fuel leaks, nitrous oxide from fertilizer, and chlorofluorocarbons (CFCs) entirely of industrial origin also contribute.
•Energy imbalance: Climate modeling predicts that human activities cause greenhouse gas and aerosol emissions that affect the Earth's energy budget. Now, for the first time, a NASA study has confirmed these predictions with direct observations: radiative forcings increase as a result of human actions, affect the planet's energy balance, and ultimately cause climate change
Natural vs. human-caused climate change
Climate has changed naturally in the past. Natural causes include volcanic eruptions, which emit aerosols that can lead to temporary cooling effects, and orbital changes described by the Milankovitch theory, which affect Earth's solar energy reception
However:
•Natural causes such as solar variability, volcanic eruptions, and orbital changes have influenced Earth's climate in the past but are not responsible for current warming
•Evidence shows current global warming cannot be explained by the Sun. Since 1750, the average amount of energy from the Sun either remained constant or decreased slightly
•If a more active Sun caused the warming, scientists would expect warming in all layers of the atmosphere. Instead, they have observed a cooling in the upper atmosphere and a warming at the surface and lower parts of the atmosphere, consistent with greenhouse gases trapping heat.
In short, while natural factors cause climate to vary over thousands of years, the rapid warming observed since the mid-20th century — about 1.1°C above pre-industrial levels — is dominated by human emissions, primarily from burning fossil fuels and deforestation.