The carbon cycle and Kyoto

The Global carbon cycle

Carbon is the universe’s fourth most common element and is the fundamental building block of all life on earth. At the global level, carbon moves between the atmosphere, the soil, living organisms, oceans and lakes, and into/out of long term storages – some movements occur in hours, while some long term storages of carbon (eg coal) have been locked up for millions of years.

The carbon cycle has been largely of academic interest prior to the emergence of climate change as an issue. Now, the ability of the human population to change the carbon cycle, releasing carbon stores (burning fossil fuels and clearing forests) that have been stable for long periods of time, has brought the carbon cycle into the forefront of science and politics. However, what is of critical importance on this website, is not the global carbon cycle, but how the cycle plays out on farms.  

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The farm carbon cycle

The carbon cycle on a farm is quite straight forward – it is simply the balance between photosynthesis (the process by which plants draw in CO2 from the air to produce sugars and release oxygen) and respiration (the process by which all living things release and use the ‘energy’ in food, drawing in oxygen and releasing CO2 to the air – ie the opposite to photosynthesis).

The vast majority of the CO2 drawn from the atmosphere and used in photosynthesis on a farm is released back into the atmosphere within the same year. Most pasture is eaten by livestock or soil organisms, and most crops are grown, harvested and consumed all within an annual cycle and therefore on average, they create no reportable emission benefits or liabilities for any carbon accounting scheme.

There are two potential exceptions to this ‘annual rule’. These activities do not prevent the eventual return to the atmosphere of all carbon captured by plants on the farm, but they can slow down that return. If the return of CO2 to the atmosphere can be slowed sufficiently, it is possible to justify including these activities in any plans to reduce the amount of greenhouse gas in the atmosphere. These exceptions are additions to the long term soil carbon store, and carbon stored in woody material, especially trees.

Another possibility is bio-char – where organic matter is heated to 350-600°C under limited oxygen to produce a charcoal like material. The converts easily-decomposable organic matter into a stable form of carbon that potentially has soil improvement and carbon sequestration benefits. The potential for bio-char has been reviewed by CSIRO.

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Kyoto obligations

 The Kyoto Protocol (Article 3.3) states that “The greenhouse gas emissions by sources and removals by sinks resulting from direct human-induced land-use change and forestry activities are limited to afforestation, reforestation and deforestation since 1990.” That is, all signatories are responsible for the net emissions from forests established since 1990 on land that was clear of forest on 31 December 1989, and from deforestation.

The Protocol goes on (Article 3.4) to outline the following, additional activities that countries may elect to count towards their emissions reduction target:

• Management of forests – ie increasing the carbon stored in plantation forests established before 1990 and all native forests under some form of management
• Revegetation – ie the establishment of woody biomass that does not meet forest (reforestation) criteria
• Management of grazing lands – ie increasing the carbon stored in soil and vegetation on grazing land
• Management of cropping land – ie increasing the carbon stored in crops and in cropping soils

In order for an offset to contribute to the goal of reducing GHG in the environment, it must be:

• Permanent: ie, the GHGs sequestered or destroyed are not later released into the environment
• Additional: ie, the GHG reductions would not have occurred though normal, good management of the system
• Verifiable: ie, the GHG reductions can be measured or can be inferred with a high degree of confidence
• Enforceable: ie, suppliers of these GHG reductions or offsets are legally liable if they fail to deliver
  

These are very challenging criteria when applied to individual farms.

It is important to note, that Australia has elected not to include the emissions from the above activities in its Kyoto obligations (ie Australia did not sign up to Article 3.4) for the following reasons as explained in the CPRS Green Paper:

• While these activities have the potential to deliver gradual reductions in emissions over time, there is the potential for major increases in emissions in the short term due to droughts and fires, over which Australia has little or no control (see below)
• There is little flexibility - if a country chooses to include any of the additional activities, it must also include, and report on, all emissions from all land nationwide on which those activities are undertaken which for Australia would be a massive undertaking
• Net emissions from soil are strongly influenced by climate, especially rainfall – reducing in wet years and rising rapidly during drought. Rainfall in many regions of Australia was above average in the base year of 1990, so any following, drier conditions would produce a net increase in Australia’s reportable emissions. To give an indication of the scale of the impact, the drought in 2002 resulted in a 70 Mt CO2-e spike in cropland emissions for that year – this is equivalent to 75% of agriculture’s reportable emissions, or 12 per cent of Australia’s base-year emissions.
• Australia is subject to major wildfires in many of its forested lands which can completely distort the national emissions reporting process. For example, fires in 2003 resulted in 190 Mt CO2-e emissions on Article 3.4 forest lands – this is more than double the reportable emissions from agriculture, and would completely overwhelming all emissions reductions from all other sectors of the economy.

It is possible for countries to include in their domestic schemes, emissions and removals that are not counted towards their Kyoto obligations.

This information is included to give a sense of how complex the issues associated with separating the positive effects on emissions from good management - from which individual landholders and Australia as a whole may wish to claim a benefit - from the negative effects of drought and fires for which no-one wants to claim responsibility. Australia is working to change some of these rules, but the process is slow and difficult.

In the meantime, the Australian Government is working to establish the Carbon Farming Initiative’, specifically to “give farmers, forest growers and landholders access to domestic voluntary and international carbon markets. For more information, link to the new toolkit section on the CFI.

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References and resources

Bruce, S. et al (2009) BRS report "Science for decision makers" – soil carbon management and carbon trading.

Chan, Y (2008), Increasing soil organic carbon of agricultural land, PrimeFact 735; NSW Department of Primary Industries.

The full text of the Kyoto Protocol and subsequent documentation is available here.

Department of Climate Change (2008) Green paper – the Carbon Pollution Reduction Scheme.

CSIRO Flagship report (2009). An Analysis of Greenhouse Gas Mitigation and Carbon Sequestration Opportunities from Rural Land Use, edited by Sandra Eady, Mike Grundy, Michael Battaglia and Brian Keating.

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