Australian Greenhouse Office

About: Australian Greenhouse Office is a based out in . It is known for research contribution in the topics: Greenhouse gas inventory & Carbon accounting. The organization has 17 authors who have published 16 publications receiving 773 citations.

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

Abstract: 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 ≤10 mg m−2 h−1 are common. Landfill sites may emit CH4 at one to three orders of magnitude greater than submerged soils. CH4 consumption rates in non-flooded, aerobic agricultural, pastoral and forest soils also vary greatly, but mean values are restricted to ≤100 μg m−2 h−1, and generally greatest in forest soils and least in agricultural soils, and decrease from temperate to tropical regions. Mitigation options for soil CH4 production primarily relate to enhancing soil oxygen diffusion through water management, land use change, minimised compaction and soil fertility management. Improved management of animal manure could include biogas capture for energy production or arable composting as opposed to open stockpiling or pond storage. Balanced fertiliser use may increase soil CH4 uptake, reduce soil N2O emissions whilst improving nutrient and water use efficiency, with a positive net greenhouse gas (CO2-e) effect. Similarly, the conversion of agricultural land to pasture, and pastoral land to forestry should increase soil CH4 sink. Conservation of native forests and afforestation of degraded agricultural land would effectively mitigate CH4 emissions by maintaining and enhancing CH4 consumption in these soils, but also by reducing N2O emissions and increasing C sequestration. The overall impact of climate change on methanogenesis and methanotrophy is poorly understood in Australia, with a lack of data highlighting the need for long-term research and process understanding in this area. For policy addressing land-based greenhouse gas mitigation, all three major greenhouse gases (CO2, CH4 and N2O) should be monitored simultaneously, combined with improved understanding at process-level.

Implications of climate change for tillage practice in Australia

Abstract: The world is experiencing climate change that in no way can be considered normal, and the challenge that this brings to agriculture is twofold. The first challenge relates to the continuing need to reduce greenhouse gas emissions that generate the changes to climate. Australia's National Greenhouse Gas Inventory estimates that agriculture produces about one-quarter of Australia's total greenhouse gas emissions (including land clearing). The main gases emitted are carbon dioxide, methane, and nitrous oxide. These gases are derived from high-value components within the agricultural production base, so reducing emissions of greenhouse gases from agriculture has the potential to provide production and financial benefits, as well as greenhouse gas reduction. Methane essentially derives from enteric fermentation in ruminants. Nitrous oxide and carbon dioxide, on the other hand, are strongly influenced, and perhaps even determined by a range of variable soil-based parameters, of which the main ones are moisture, aerobiosis, temperature, amount and form of carbon, organic and inorganic nitrogen, pH, and cation exchange capacity. Tillage has the potential to influence most of these parameters, and hence may be one of the most effective mechanisms to influence rates of emissions of greenhouse gases from Australian agriculture. There have been substantial changes in tillage practice in Australia over the past few decades – with moves away from aggressive tillage techniques to a fewer number of passes using conservative practices. The implications of these changes in tillage for reducing emissions of greenhouse gases from Australian agriculture are discussed. The second challenge of climate change for Australian agriculture relates to the impacts of climate change on production, and the capacity of agriculture to adapt where it is most vulnerable. Already agriculture is exposed to climate change, and this exposure will be accentuated over the coming decades. The most recent projections for Australia provided by the CSIRO through the Australian Climate Change Science Programme, indicate that southern Australia can expect a trend to drying due to increased temperatures, reduced rainfalls, and increased evaporative potentials. Extremes in weather events are likely also to become more common. We anticipate that climate change will become an additional driver for continued change in tillage practice across Australia, as land managers respond to the impacts of climate change on their production base, and governments undertake a range of activities to address both emissions reduction and the impacts of climate change in agriculture and land management.