Final answer:
Humans have changed the carbon cycle over the last 100 years by burning fossil fuels, deforestation, and changes in land use. These activities have increased CO2 levels, leading to global warming and disrupting the natural balance of carbon exchange.
Step-by-step explanation:
Over the last 100 years, human activities have significantly altered the carbon cycle. The burning of fossil fuels, such as coal, oil, and gas, has released vast amounts of carbon dioxide (CO2) into the atmosphere. Deforestation has also contributed to increased CO2 levels as trees absorb CO2 during photosynthesis.
These human activities have resulted in a rapid increase in atmospheric CO2 concentrations, leading to the greenhouse effect and global warming. The excess CO2 traps heat in the atmosphere, causing changes in climate patterns and impacting ecosystems worldwide.
Furthermore, the carbon cycle has been disrupted by changes in land use, such as urbanization and agriculture. Converting forests into urban areas or farmland reduces the amount of vegetation available to absorb CO2, disrupting the natural balance of carbon exchange between the atmosphere, land, and oceans.
Learn more about Impact of human activities on the carbon cycle