Human activities contribute to climate change primarily by increasing the concentration of greenhouse gases in the atmosphere, which enhances the natural greenhouse effect and leads to global warming.

Key Human Activities Contributing to Climate Change

• Burning Fossil Fuels: The combustion of coal, oil, and natural gas for electricity, heat, and transportation releases large amounts of carbon dioxide (CO2), the largest single contributor to global warming. This activity alone emitted an estimated 37.4 billion tonnes of CO2-equivalent gases in 2023, with coal-fired power stations being the largest source

• Deforestation: Cutting down forests reduces the number of trees that absorb CO2 during photosynthesis. When trees are cut or burned, the carbon stored in them is released back into the atmosphere, increasing CO2 levels

• Agriculture and Livestock Farming: Livestock such as cows and sheep produce methane (CH4) during digestion, a greenhouse gas more potent than CO2 but shorter-lived. Agricultural practices also release nitrous oxide (N2O) through fertilizer use and soil management. Methane emissions also come from rice paddies and manure management

• Industrial Processes and Use of Fluorinated Gases: Manufacturing and use of chemicals like chlorofluorocarbons (CFCs) and other fluorinated gases release potent greenhouse gases with warming effects thousands of times greater than CO2

• Waste Management: Decomposition of organic waste in landfills produces methane, adding to greenhouse gas emissions

Mechanism of Contribution

These activities increase the concentration of greenhouse gases-CO2, methane, nitrous oxide, and fluorinated gases-in the atmosphere. These gases trap heat by absorbing infrared radiation emitted from the Earth's surface, preventing it from escaping into space, thus warming the planet. This human-induced enhancement of the greenhouse effect is the main driver of observed global warming since the industrial era began around 1750

Impact

• Atmospheric CO2 levels have risen nearly 50% above pre-industrial levels.
• Global average temperatures have increased by about 1.1°C since pre-industrial times, with warming continuing at roughly 0.2°C per decade.
• This warming disrupts climate systems, leading to more extreme weather events, altered precipitation patterns, and risks to ecosystems and human health

In summary, human activities-especially fossil fuel burning, deforestation, agriculture, and industrial processes-significantly increase greenhouse gas emissions, driving climate change and global warming