Research

The potential impact of climate change on Australia's soil organic carbon resources

Peter R Grace¹ , Wilfred M Post² and Kevin Hennessy³

¹  School of Natural Resource Sciences and Institute for Sustainable Resources, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia

²  Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

³  CSIRO Marine and Atmospheric Research, Private Bag No. 1, Aspendale, VIC 3195, Australia

author email corresponding author email

Carbon Balance and Management 2006, 1:14doi:10.1186/1750-0680-1-14

Published:	6 December 2006

Abstract

Background

Soil organic carbon (SOC) represents a significant pool of carbon within the biosphere. Climatic shifts in temperature and precipitation have a major influence on the decomposition and amount of SOC stored within an ecosystem and that released into the atmosphere. We have linked net primary production (NPP) algorithms, which include the impact of enhanced atmospheric CO₂ on plant growth, to the SOCRATES terrestrial carbon model to estimate changes in SOC for the Australia continent between the years 1990 and 2100 in response to climate changes generated by the CSIRO Mark 2 Global Circulation Model (GCM).

Results

We estimate organic carbon storage in the topsoil (0–10 cm) of the Australian continent in 1990 to be 8.1 Gt. This equates to 19 and 34 Gt in the top 30 and 100 cm of soil, respectively. By the year 2100, under a low emissions scenario, topsoil organic carbon stores of the continent will have increased by 0.6% (49 Mt C). Under a high emissions scenario, the Australian continent becomes a source of CO₂ with a net reduction of 6.4% (518 Mt) in topsoil carbon, when compared to no climate change. This is partially offset by the predicted increase in NPP of 20.3%

Conclusion

Climate change impacts must be studied holistically, requiring integration of climate, plant, ecosystem and soil sciences. The SOCRATES terrestrial carbon cycling model provides realistic estimates of changes in SOC storage in response to climate change over the next century, and confirms the need for greater consideration of soils in assessing the full impact of climate change and the development of quantifiable mitigation strategies.