Final answer:
Large-scale human impacts on the climate began around 8000 years ago, with significant acceleration over the past 100 years due to the burning of fossil fuels and industrialization. The correct answer is option C).
Step-by-step explanation:
Large-scale human impacts on the climate may have started around 8000 years ago, aligning with option C. Human activities, particularly the burning of fossil fuels, have significantly altered the composition of the atmosphere and contributed to the greenhouse effect. Over the past 100 years, the Earth's temperature has risen approximately as much as it did over the previous 4000 years, indicating a rapid change brought on by industrialization. Prior to the Industrial Revolution, climate changes were primarily driven by natural factors, such as the Milankovitch cycles, solar energy variations, and volcanic eruptions.
The increase in atmospheric concentration of CO2 has been particularly notable since the beginning of industrialization, and human activity is the overwhelming driver of this change. If Earth continues to become significantly hotter, effects could include an increased rate of melting of the polar ice caps. This would affect modern civilization by contributing to rising sea levels, increased frequency of extreme weather events such as hurricanes, and seismic disruptions.