Question

Describe how humans have affected the numerous pathways and reservoirs in the carbon cycle that have contributed to climate change. Find three examples where positive feedback in the environment is likely contributing more carbon dioxide to the atmosphere that is not a result of human activities.

Answer 1

Ans. Nature maintains the balance in the ecosystem through different biogeochemical cycles and energy flow. Carbon cycle is a balance between the influx and efflux of carbon into and from the environment. So the concentration of the total carbon usually does not change significantly. However, human activities have altered the carbon cycle by offsetting it. Relentless use of fossil fuels is the biggest contributor to carbon dioxide increase. Coal fired power plants generate electricity in all the countries around the globe and is the largest anthropogenic source of CO2. Then there are petrochemical industries, agricultural practices and burning fossil fuels for cooking and other purposes also give rise to CO2. Moreover with increase in CO2 sources there have been decreasing sinks of CO2. Deforestation is the prime reason behind this. Oceans are considered the biggest source of CO2 but they maintain CO2 concentration within through diffusion from the atmosphere. Trees and plants are the next significant reservoir of CO2. However, when the trees and plants are reduced, the maximum concentration of CO2 goes into the oceans, thus leading to not only acidification of the oceans, and disturbing the equilibrium of CO2 between the atmosphere and oceans. So more CO2 is absorbed by the oceans. However, when the concentration of CO2 exceeds that of the atmosphere, the oceans release the excess CO2 back into atmosphere. Thus the concentration of CO2 in the atmosphere keeps on increasing.

This increasing CO2 concentration in the atmosphere has led to the increase in temperature since it is a green house gas. The increasing temperature has led to global warming and its chronic effect has led to what we call climate change. It has led to shifting of seasons, increasing heat waves and cold waves with highest maximum and lowest minimum temperatures during summer and winter months. It is also leading to unequal distribution of precipitation. It is leading to flood and drought in different parts of the world. There has been increase in propensity and frequency of tropical cyclones, flooding and inundation of coastal areas due to climate change. One more contribution to the climate change is the ignorance of people towards the acceptance of the fact that global warming is real.

Positive feedback refers to the changes in a system which will amplify the result or outcome. In the context of climate change, three examples of natural contribution to CO2 addition to the atmosphere are as follows:

• Volcanic eruptions emit huge amount of CO2 which lead to its addition to the atmosphere. Although research says that volcanic eruptions lead to cooling due to release of sulfur and sulfate aerosols, but it is short term. In the long run, there is significant accumulation of CO2 and thus increase in CO2 concentration and warming of the earth.
• Decomposition of organic materials naturally like plant and animal debris lead to release of CO2. This is because organic matter breaks down into CO2 and water in the presence of oxygen.
• Respiration by living organisms also leads to release of CO2. It is the biochemical process by which organic matter within the body are broken down into simpler substances namely CO2, water and energy.