Magnitude and biophysical regulators of methane emission and consumption in the Australian agricultural, forest, and submerged landscapes: a review

• Published in: Plant and soil 2008-08, Vol.309 (1-2), p.43-76
• Main Authors: Dalal, R. C, Allen, D. E, Livesley, S. J, Richards, G
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural soils; Agronomy. Soil science and plant productions; Animal manures; Animal wastes; Animal, plant and microbial ecology; Anthropogenic factors; Biogas; Biological and medical sciences; Biomedical and Life Sciences; Biophysics; Carbon dioxide; Climate change; Cultivation; desert soils; Ecology; Emission inventories; Emissions; Environmental impact; Farm buildings; Forest soils; Forestry; Fundamental and applied biological sciences. Psychology; Global warming; Grain cultivation; Greenhouse effect; Greenhouse gases; Land use; Landscape ecology; Life Sciences; Methane; Methane emission; Methane oxidation; Methanogenesis; Nitrous oxide; Oxidation; Pasture; Plant Physiology; Plant Sciences; Pollutant emissions; Regular Article; Rice soils; Savanna soils; Soil air; Soil fertility; Soil management; Soil Science & Conservation; Soil water; Soils; Water management; Water use; Wetland soils; Wetlands
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-007-9446-7

Increases in the concentrations of atmospheric greenhouse gases, carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) due to human activities are associated with global climate change. CO₂ concentration in the atmosphere has increased by 33% (to 380 ppm) since 1750 ad, whilst CH₄ concentration has increased by 75% (to 1,750 ppb), and as the global warming potential (GWP) of CH₄ is 25 fold greater than CO₂ it represents about 20% of the global warming effect. The purpose of this review is to: (a) address recent findings regarding biophysical factors governing production and consumption of CH₄, (b) identify the current level of knowledge regarding the main sources and sinks of CH₄ in Australia, and (c) identify CH₄ mitigation options and their potential application in Australian ecosystems. Almost one-third of CH₄ emissions are from natural sources such as wetlands and lake sediments, which is poorly documented in Australia. For Australia, the major anthropogenic sources of CH₄ emissions include energy production from fossil fuels (~24%), enteric fermentation in the guts of ruminant animals (~59%), landfills, animal wastes and domestic sewage (~15%), and biomass burning (~5%), with minor contributions from manure management (1.7%), land use, land-use change and forestry (1.6%), and rice cultivation (0.2%). A significant sink exists for CH₄ (~6%) in aerobic soils, including agricultural and forestry soils, and potentially large areas of arid soils, however, due to limited information available in Australia, it is not accounted for in the Australian National Greenhouse Gas Inventory. CH₄ emission rates from submerged soils vary greatly, but mean values