A Review on Methods to Estimate CH₄ and N₂O Fluxes in Terrestrial Ecosystem

It has been found in the last 3–4 decades that different ecosystems in the tropical regions contributed maximum trace gases (CH₄ and N₂O) to atmosphere. Terrestrial ecosystems in tropics, sub-tropics and in temperate regions are the well-known sources and sinks of important GHGs (green house gases). Nowadays, developing countries of Asia Pacific regions are contributing a maximum amount of these trace gases at the global scale. Anthropogenic activities and changing environmental conditions alter the dynamics of different ecosystems that stimulate GHGs emission in the last few years. A higher concentration of CO₂ and temperature in soil enhance microbial activity. The techniques for sampling, estimation and future prediction of fluxes of these trace gases from different types of ecosystem are still undergoing changes with the advancement in knowledge of microbiology, geology and technology. This review discusses GHG, mainly methane (CH₄) and nitrous oxide (N₂O) emission estimated from different ecosystems, advancement in estimation technology and the key controlling factors for their emission around the world.