Climate change may interact in complex ways with land degradation in their effects on land management. For example, dryland salinity is linked to climate change in at least six ways.

Not only are there some remarkable parallels between dryland salinity and climate change (PD#50), but there are also some close links between them. It is one example of the way that climate change, to the extent that it does occur, will interact with other natural resource management problems. Here are the obvious links with dryland salinity.

1. Changes in rainfall levels and rainfall patterns will affect rates of groundwater rise. To the extent that climate change involves lower rainfall, the salinity threat is likely to be reduced, although some work suggests that rainfall in summer may actually rise in some regions of Australia.
2. Climate change (rainfall, temperatures and frost risk) will change the yields of different land uses, affecting the relative attractiveness of land uses for salinity-management.
3. Climate change may alter production patterns internationally, driving changes in the relative prices of agricultural products, affecting the relative attractiveness of land uses for salinity-management.
4. Changes in yields and prices affect the overall profitability of farms, which affects the capacity of farmers to adopt some of the salinity-management practices that have high up-front costs.
5. If climate change policy leads to the establishment of markets for carbon credits, this would influence the adoption of woody perennials, which are recommended for salinity management in some cases.
6. Adoption of woody perennials for purposes of salinity management would sequester carbon and contribute, at least a little, to mitigation of climate change.

These links will affect the performance of policies for both salinity and climate change. They complicate the evaluation of either sort of policy.

Michele John has conducted a detailed analysis of the interaction between climate change and dryland salinity in the eastern wheatbelt of Western Australia. Her analysis suggests that effects on the performance of perennial options (link 2 above) is likely to be less important than impacts on farmer capacity to adopt innovations (link 4).

In addition to Michele’s analysis, I would make the following observations about the other links. Link 5 is not likely to have a major influence on land-use decisions, as the scale of carbon credits being offered in Canada and Europe, who have signed the Kyoto Protocol, is too small to swing decisions unless the decision happened to be finely balanced to start with. The influences of links 1 and 3 are highly uncertain but could be significant. The significance of link 6 would be tiny in terms of reducing climate change.

Overall, climate change in general may interact with land degradation in effects on land management. Those interactions are likely to be complex and highly case-specific. Making sense of it requires a detailed farm-level analysis (and potentially larger scale analysis).

David Pannell, The University of Western Australia

Further Reading

John, M., Pannell, D.J. and Kingwell, R. (2005). Climate change and the economics of farm management in the face of land degradation: Dryland salinity in Western Australia. Paper presented at International Policy Forum on Greenhouse Gas Management, Victoria, British Columbia, April 28-29 2005. full paper in HTML (218K)