Consider the following: 1. Rice fields 2. Coal mining 3. Domestic animals 4. Wetlands Which of the above are sources of methane, a major greenhouse gas?

All four listed items are established sources of methane. Methane is produced by anaerobic decomposition in flooded rice paddies and from bacterial action in submerged soils, making rice fields a significant agricultural source; livestock (domestic ruminants) emit methane via enteric fermentation and manure decomposition [1]. Wetlands are the largest natural source of methane due to saturated, oxygen-poor soils that favor methanogenesis [2]. Fossil-fuel activities including coal mining release methane as fugitive emissions during extraction and handling, adding a substantial anthropogenic source [3]. Consequently, rice fields, coal mining, domestic animals, and wetlands each contribute to atmospheric methane and its greenhouse effect.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 7: Climate Change > 2. greenhouse gases > p. 11
2. [2] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 17: Climate Change > 17,3.3. Methane > p. 256
3. [3] https://en.wikipedia.org/wiki/Methane_emissions