There is a widespread belief among scientists and agronomists that Science has proved that Australian soils have little potential to sequester Carbon. In fact, no scientific studies have tested the potential of Australian soils to sequester carbon where ‘potential’ means the maximum possible under ideal conditions . The research program on which the National Carbon Accounting System (NCAS) was based suffered from methodological flaws which led to gaps in the data and unjustified conclusions. The authors of one major report have agreed that the paired sites chosen for analysis were unrepresentative of the land management techniques that are widespread today. Scientists have pointed out that the case studies reviewed in another major report are out of date.
Analysis of Technical Reports 34* and 43, the core data reports for the construction of the NCAS inventory of emissions for soils, reveals that the data sets are incomplete, focusing almost exclusively on conventional rather than regenerative land management techniques. It studied only soils managed in ways that caused losses of carbon rather than soils managed in ways that capture and store carbon (ie. regenerative land management techniques such as biological farming, time controlled grazing management, pasture cropping, etc.)
Farming has changed in the 20 years since most of the studies reviewed for NCAS were done. The scientific methodology was flawed because it did not choose a representative range of samples. For this reason, there are gaps in the data sets.
Therefore the data cannot support the conclusions being drawn from it. The authors of these reports warned against relying on them for definitive conclusions
The consultant hired to assess the data sources was also concerned**: “There are also considerable deficiencies in the completeness of the data… In many established agricultural areas, there are practical difficulties in finding true pairs… The approach is limited by gross lack of data…”
The Australian Greenhouse Office admitted that the data was insufficient. “Development of the NCAS was undertaken with the clear understanding that data would be imperfect, but that the significance of data limitations could be assessed only in a functional integrated system.” ***
The AGO took a ‘fix it in the mix’ approach: “The tacit acceptance of variability in data provides for a proper focus on matters of accuracy and bias, rather than on potentially unachievable precision.” The Agency believed the sheer weight of data points would carry the day, provided there was no bias in the inputs: “Over a large sample … a national inventory derived from an aggregation of fine-scale events can provide a robust central estimate provided inputs are not biased.” But the inputs were biased.
Most official studies recorded poor carbon performance because they studied only traditional techniques which are destructive of soil carbon.
They did not find sequestration because they weren’t looking for it. They were looking for declining carbon. They found it. There are several trials underway to fill the gaps, further evidence that the gaps existed and the conclusions were unsustainable.
Despite the lack of official data, there are many indications that Australian soils can sequester significant amounts of carbon.****
*Technical Report No. 34 Paired Site Sampling for Soil Carbon Estimation – NSW, National Carbon Accounting System, Australian Greenhouse Office, January 2003
**Estimation of Changes in Soil Carbon due to Changed Land Use National Carbon Accounting System - Technical Report No. 2 November 1999
***“Methods for Estimating Land Use Change Emissions “, Factsheet, National Carbon Accounting System, Australian Greenhouse Office, August 2002
****Senior CSIRO soil scientist Jeff Baldock says there is today no technical barriers to a fully-functioning market in soil carbon, and that such a market could make it ‘more economic to farm for carbon than to farm for yield.’ (ABC Rural Radio, October 2007, Orange Field Days.)
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