Answer:
There are several natural events that can contribute to an increase in carbon dioxide (CO2) levels, but the most significant one is the process of respiration by living organisms, including plants and animals.
During respiration, living organisms take in oxygen and release carbon dioxide as a waste product. Plants also release carbon dioxide during the process of cellular respiration, but they also absorb carbon dioxide through photosynthesis, which helps to balance the carbon cycle.
Another natural event that can contribute to an increase in CO2 levels is volcanic eruptions. Volcanoes release large amounts of carbon dioxide, along with other gases and particles, into the atmosphere. While these emissions can have a short-term effect on local air quality and climate, they do not significantly contribute to the long-term increase in atmospheric CO2 levels.
Additionally, wildfires can also contribute to an increase in CO2 levels. When forests and other vegetation burn, they release carbon dioxide into the atmosphere, but again, the impact is relatively short-term.
However, human activities such as burning fossil fuels, deforestation, and industrial processes are the primary drivers of the long-term increase in atmospheric CO2 levels, which has contributed to global climate change.