Global food security and sustainable agriculture systems in a carbon trading future

The South Australian Rural Media Association recently invited CSIRO’s Dr Jeff Baldock to give a presentation on soil carbon in which he addressed two key strategies:

The first strategy is building soil carbon to reverse past degradation to achieve more sustainable farming systems. This strategy is particularly important in maximising soil moisture retention as we experience dryer years; also to build the productive capacity of the land, as well as to reduce the use of nitrogenous fertilizers, that is also implicated in generating greenhouse gases.

According to Dr Baldock estimates of losses of soil carbon in Australian soils range from 20% to 70% depending on the farming systems, so there is significant potential to rebuild soil carbon levels. However it also needs to be recognised that there are upper limits on capacity to store carbon in the soil, and the new farming systems need to be continued to maintain the higher soil carbon levels.

Farming practices that destroy soil carbon include, fallowing, cultivation, stubble burning or removal, and overgrazing. Changes in farming systems including destocking rangelands, no till systems, changing crops types, and moving cropping lands to pasture all have a positive impact on soil carbon levels.

The trade off to building soil carbon levels is less carbon is available for remove from the property as a productive crop, which obviously has economic implications for the farmer. The second carbon strategy discussed by Dr Baldock was building soil carbon for greenhouse gas abatement, linked to Carbon Credits and Carbon Trading. Given only 6% of Australia is intensively managed farming systems, it is this highly productive land that would be targeted for proposed CO2 abatement schemes. The danger is depending on the value of Carbon Credits, farmers may decide to move even more carbon into the soil, therefore even less into crop output.

As we move to achieve more sustainable farming systems, and implement Carbon Trading schemes, there are also implications for global food supply and global food security. For instance under a future high price Carbon Credit regime the optimal level of food production per unit of land may be even less then that required by sustainable farming practices.

The world has already seen the market distortion from US Government’s Ethanol Mandate on global food supply. US farmers currently grow 40% of global corn production. US corn production for ethanol has risen to 36%, for the first time above stock feed at 35%, with the remaining crop going to food and other manufacturing (10%) and exports (19%).

The question is will we observe a similar distortion to global food supply resulting from the Australian Government’s proposed Carbon Tax legislation?

Further information at: CSIRO