Greenhouse gases (GHGs) are atmospheric compounds that trap heat and maintain the Earth's temperature, making the planet habitable for diverse species including humans. The primary greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases. These gases absorb and emit infrared radiation, creating the 'greenhouse effect', which is vital for life by regulating the Earth's temperature. However, an increase in these gases due to human activities such as burning fossil fuels, deforestation, and industrial processes has led to excessive warming, contributing to global climate change.
Carbon dioxide is the most prevalent greenhouse gas emitted through human activities, especially from the combustion of fossil fuels like coal, oil, and natural gas. This accounts for a significant portion of the energy used in transportation, electricity, and manufacturing industries. The concentration of CO2 in the atmosphere has increased by about 50% since the Industrial Revolution, highlighting a sharp rise from pre-industrial levels due to increased anthropogenic activities. This surge significantly enhances the natural greenhouse effect, leading to an increase in Earth's average surface temperature, a phenomenon commonly known as global warming.
Methane, another potent greenhouse gas, is about 25 times more effective at trapping heat in the atmosphere than carbon dioxide over a 100-year period. Methane emissions mainly arise from natural sources like wetlands, but significant amounts are released from agricultural practices, waste management, and the production and transport of coal, oil, and natural gas. For instance, rice paddies, enteric fermentation from ruminant animals, and landfills are major anthropogenic sources of methane, each contributing considerably to its atmospheric concentrations.
Nitrous oxide, though less abundant, is around 298 times more potent than carbon dioxide over a century. It's primarily released through agricultural and industrial activities, as well as combustion of fossil fuels and biomass. Soil management practices, such as the use of synthetic and organic fertilizers, lead to significant N2O emissions. The use of 'fluorinated gases', though less in quantity compared to other greenhouse gases, also plays a critical role due to their high global warming potential. These synthetic compounds are mostly used in air conditioning and refrigeration systems. Efforts to mitigate GHG emissions include enhancing energy efficiency, switching to renewable energy sources, improving waste management, and developing sustainable agricultural practices, all critical steps in combating the adverse effects of climate change.