Anthropogenic Causes of Climate Change
Definition
Anthropogenic
Anthropogenic refers to changes in the environment caused by human activities.
- Climate change is driven by both natural and anthropogenic (human-caused) factors.
- In recent times, the anthropogenic causes of climate change have become a primary focus, particularly those related to the release of greenhouse gases such as carbon dioxide (CO₂) and methane (CH₄) into the atmosphere.
- Human activities have significantly increased the concentrations of carbon dioxide (CO₂) and methane (CH₄) in the atmosphere.
- These gases trap heat, amplifying the greenhouse effect and driving global warming.
Definition
Greenhouse gas
A greenhouse gas is a gas that contributes to the greenhouse effect by absorbing infrared radiation
- The greenhouse effect is a natural process that warms the Earth's surface.
- However, human activities have intensified this effect, leading to climate change.
Anthropogenic Increase in Carbon Dioxide (CO2)
1. Burning of Fossil Fuels
- One of the primary anthropogenic sources of carbon dioxide is the burning of fossil fuels, including coal, oil, and natural gas.
- These fuels are used in energy production, transportation, and industrial activities.
- When fossil fuels are burned, the carbon stored in them is released into the atmosphere as carbon dioxide.
- Power plants that burn coal to generate electricity release vast amounts of CO2 into the atmosphere.
- Similarly, cars and trucks that run on gasoline emit CO2 when the fuel is combusted.
2. Deforestation
- Another significant contributor to CO2 emissions is deforestation.
- Trees naturally absorb CO2 during photosynthesis, and when forests are cleared for agriculture, urban development, or logging, this carbon is released back into the atmosphere.
- Additionally, the loss of trees reduces the Earth's ability to absorb CO2, compounding the problem.
The clearing of tropical rainforests for agricultural land, particularly in regions like the Amazon, is a major source of CO2 emissions.
ExampleThe Cerrado in Brazil, a vast savanna, is being cleared for agriculture, releasing significant amounts of $CO_2$.
3. Industrial Processes
- Certain industrial processes, such as cement production and the manufacture of steel, release CO2 as part of their chemical reactions.
- In cement production, limestone (CaCO3) is heated to produce lime (CaO), releasing CO2 as a by-product.
The production of cement accounts for about 5-7% of global CO2 emissions.
Since the Industrial Revolution, atmospheric $CO_2$ levels have risen from 280 ppm (parts per million) to over 415 ppm today.
Anthropogenic Increase in Methane (CH4)
1. Agriculture
- Agricultural activities are the largest source of anthropogenic methane emissions.
- Methane is released during the digestive processes of ruminant animals (like cows, sheep, and goats) through enteric fermentation.
- Methane is also produced in manure management and rice paddies.
- Livestock farming produces large quantities of methane due to enteric fermentation in cows and other ruminants.
- Methane is also emitted from the decomposition of manure stored in lagoons
2. Landfills
- Landfills, where organic waste such as food, paper, and yard clippings decompose, are another significant source of methane.
