Greenhouse gases and the greenhouse effect are naturally occurring phenomena. The earth’s climate is not static and has been undergoing changes in greenhouse gas concentration for millennia, evidence of which has been found in ice cores and geological data collected by scientists. However, there is current evidence to suggest that as a result of human activities, the proportion of greenhouse gases are increasing. The primary greenhouse gases in Earth’s atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The significant increase in greenhouse gases is resulting in greater absorption of the sun’s radiation, trapping heat and increasing the natural greenhouse effect of the atmosphere. The result of extra heat in the atmosphere is increasing the temperature of the earth’s surface (and troposphere), resulting in global warming. Climate change refers to long-term changes in climate, including average temperature and rainfall.
Read more on climate change from the Department of Environment.
Carbon (C) is the basic building block for all life on and in earth. Vibrant, living soils require air and water as well as soil carbon. Carbon is the driver for every aspect of soil health and soil function. Carbon begins and ends its journey as a gas, carbon dioxide (CO2). Plants with green leaves undertake photosynthesis and lots of the carbon is released right back into the air by respiration or decay of plant material. Some of it can become soil organic matter, often called humus. This organic matter can persist in soils for hundreds or even thousands of years.
Terrestrial ecosystems, both plants and soils, provide an attractive mechanism for carbon sequestration because we can manage them. We can manage plant growth to increase plants’ capacity to uptake carbon dioxide. And we can manage plant growth so that soils in turn store carbon for long periods of time.
Carbon farming is the process of managing soils, vegetation, water and animals to to increase the amount of carbon stored in the soil and vegetation (sequestration) and to reduce greenhouse gas emissions from livestock, soil or vegetation (avoidance or abating).
Avoidance, abatement and reduction
Agriculture is responsible for 14 per cent of Australia’s greenhouse gas emissions, with livestock and agricultural soils the largest sources of the potent greenhouse gases, methane and nitrous oxide–released through activities such as machinery use, transport, production and use of fertiliser, and rumen fermentation from animals. The Emissions Reduction Fund of the Australian Government (Department of the Environment and Energy) provided incentives for emissions reduction activities across the Australian economy. Anyone wanting to undertake a carbon farming project to sell carbon offsets has to use an approved methodology. There are approved methodologies for soil carbon, livestock, revegetation, savanah burning, avoided deforestation and energy efficiency available for project proponents.
It has been estimated that terrestrial plants produce about 125Gt of dry matter per year, of which about 50 per cent is carbon. Sequestered carbon is released back into the atmosphere when land-use change permanently removes or reduces plant biomass or soil organic carbon, or when fossil fuels are burnt. Activities such as reforestation, afforestation and revegetation as well as rangelands restoration can be used to sequester atmospheric carbon. The sequestration potential of most WA soils is relatively low and strongly dependent on soil type, climate and land use.
Rangelands NRM has worked on a number of carbon farming related projects, through the Carbon Farming Awareness Program.