The human activity that began approximately 160 years ago and provides the strongest evidence that humans are responsible for increased atmospheric carbon dioxide concentrations is the widespread burning of fossil fuels, particularly the combustion of coal, oil, and natural gas. This activity releases large amounts of carbon dioxide into the atmosphere as a byproduct, contributing to the greenhouse effect and climate change. The analysis of carbon isotopes in the atmospheric carbon dioxide provides clear evidence that the increase in carbon dioxide concentrations is primarily due to the burning of fossil fuels, as the isotopic signature of fossil fuel emissions differs from natural carbon sources. This evidence points to human activities as the main driver of the increased atmospheric carbon dioxide concentrations.
