Indicator: LD-05 Terrestrial carbon loss rate and rate of land carbon sequestration

Data

Australia-wide annual soil carbon loss
Year Area Reported C Stock Loss in Soil (t) C Stock of Soil in area reported (t)
1990 10,835,879 4,928,797 675,347,625
1991 11,293,601 2,004,488 673,343,137
1992 11,719,649 2,897,911 670,445,226
1993 12,124,093 1,556,567 668,888,659
1994 12,514,305 1,102,088 667,786,571
1995 12,870,910 2,168,372 665,618,199
1996 13,224,008 2,866,663 662,751,536
1997 13,548,446 1,480,221 661,271,315
1998 13,859,607 5,158,127 656,113,188
1999 14,177,365 2,464,017 653,649,171
2000 14,557,985 3,387,580 650,261,592
2001 14,938,784 508,677 649,752,915
2002 15,259,340 1,365,802 648,387,113
2003 15,556,871 2,967,336 645,419,777
2004 15,882,379 1,423,024 643,996,753

Source: Australian Greenhouse Office, unpublished paper, 2006

What the data mean

The data show that it is only the forestland conversion to cropland and grassland that have significant impacts on soil carbon stocks. Australia reports ‘0’ emissions against other categories. The forest land conversion to both cropland and grassland includes all deforestation on these lands that has occurred since 1972, when the land cover change record commenced. The table shows the areas, soil carbon stock changes and estimated soil carbon stock in these areas of land since 1990.

Across all land uses, in the area reported, about 36 million tonnes of soil carbon has been lost, through emissions and removal of vegetation or product, since 1990, The net loss of soil carbon over the period is about 31 million tonnes.

Data Limitations

Issues for which this is an indicator and why

Land — Land condition - Soil stability and quality 

Carbon is an essential component of the chemistry of all organisms. Carbon cycles between the atmosphere, the soil, the vegetation that grows in the soil and the other life that inhabits and feeds on the vegetation. Soil carbon is essential for plant growth and carbon is returned to the soil through the decay of organic matter. The condition of the land is dependent on the availability of terrestrial carbon. Rates of loss and sequestration are indicative of the carbon status of the land and therefore of this aspect of its condition.

Other indicators for this issue:

Land — Direct pressure of human activities on the land - Soil loss and loss of soil quality 

Removal of terrestrial carbon through removal of vegetation and other life forms (eg the clearing or burning of vegetation and the harvesting of crops or of animals that have grazed on the vegetation), places pressure on the land by reducing the availability of soil carbon. Removal of carbon from the land inhibits the reestablishment of vegetation. Rates of loss and sequestration are indicators of this pressure.

Other indicators for this issue:

Land — Contributions and pressures between the land and the atmosphere - Climate 

When terrestrial carbon is released into the atmosphere as carbon dioxide, either through burning, natural decay or grazing, it can contribute to changing atmospheric composition and ultimately to climate change. Rates of carbon loss and sequestration give an indication of the volumes of terrestrial carbon that are being released as atmospheric carbon and preserved as terrestrial carbon.

Other indicators for this issue:

Biodiversity — Pressures on biodiversity - Climate variability 

Although changes in soil carbon in Australia is a relatively small contributor to global climate change, soil carbon and biomass are, along with greenhouse gas emissions, a measure of Australia’s contribution to global climate change.

Other indicators for this issue:

Atmosphere — Climate variability and change - Greenhouse 

Loss of soil carbon to the atmosphere increases atmospheric greenhouse gas concentrations. Rates of carbon loss and sequestration give an indication of the volumes of terrestrial carbon that are being released as atmospheric carbon and preserved as terrestrial carbon.

Other indicators for this issue:

Further Information