What human activity is associated with increased levels of methane in the atmosphere?

Agricultural practices are closely associated with increased levels of methane in the atmosphere due to several factors. One of the primary sources of methane in agriculture is enteric fermentation, which occurs in the digestive systems of ruminant animals such as cows and sheep. These animals produce methane as they digest their food, and significant quantities are released into the atmosphere when they burp.

Additionally, agricultural practices involve the decomposition of organic matter in anaerobic conditions, such as in rice paddies, where waterlogged conditions lead to the production of methane by microorganisms. Furthermore, the management of manure from livestock can also contribute to methane emissions if not handled properly, as decomposing manure can release methane gas.

In contrast, reforestation efforts typically aim to absorb carbon dioxide rather than produce methane, and wind energy production has minimal impact on methane levels. Urbanization can cause an increase in overall greenhouse gas emissions but is not directly linked to methane as prominently as agricultural practices. Hence, agricultural practices are the key contributor to elevated methane levels in the atmosphere.