Carbon consumers

Excluding agriculture won’t get us to net zero emissions. But a few policy tweaks could transform Australia’s 400 million hectares of farmland into net consumers of carbon sequestered into the soil. By James Mathias.

This opinion piece first appeared in the Australian Financial Review on 15 February.

No one should underestimate how hard it will be to achieve net-zero greenhouse gas emissions by 2050. Some suggest that excluding agriculture, as New Zealand has done, will make the task easier. On the contrary. If we write off the potential of agriculture to help correct the carbon imbalance, it is hard to see how a country like ours could ever meet the target. By making small but important changes to the way we farm, Australia’s 400 million hectares of agricultural land can be transformed into net consumers of carbon sequestered into the soil.

So far, the greenhouse gas policy debate has focused almost exclusively on the supply side. It has concentrated on methods of reducing the volume of emissions, with disproportionate focus on the energy sector. If we are serious about achieving a net zero target in just 29 years, we must also look at the demand side of the ledger: finding safe and productive ways to restore the delicate balance between atmospheric, terrestrial and marine carbon.

By improving the way we farm, the agriculture sector can become a net consumer of atmospheric carbon through photosynthesis, the natural process by which plants combine carbon, water and heat from the sun to increase the level of soil organic carbon. Since Australian farming soils in aggregate are low by world standards, the potential to absorb carbon and turn it into productive use is huge.

Scientists estimate that 25 gigatonnes (or 25 billion tonnes) of organic carbon is already buried in Australia’s topsoil, the equivalent of 180 years of emissions at the current level. With 5.2 per cent of the global land mass but just 3.5 per cent of the world’s soil carbon, Australia is strategically placed to add significant amounts to that total in years to come.

Increasing soil organic carbon is the single most useful step we can take to remove excessive carbon dioxide from the atmosphere. A modest 0.5 per cent increase in soil carbon would be the equivalent of turning off Australia’s coal-fired power stations for three years.

The benefits of soil carbon, however, go further than sequestration. Even without the imperative to restore the carbon balance, richer soils are more productive and require fewer inputs. They retain more water, helping reduce the damage caused by runoff and building drought resilience. Increasing soil carbon content improves biodiversity, both within the paddock and in the surrounding water catchment area.

Switching to carbon farming requires a relatively small capital investment. The farming techniques that increase the amount of soil carbon are well developed and uncomplicated and are not achieved by men and women in lab coats with beakers and Bunsen burners. In essence techniques preserve ground cover and avoid the exposure of bare earth. Among methods commonly adopted are GPS mapping for seed and fertiliser application, precision targeting of weeds, rotational grazing and a more scientific approach to stock management.

For example, no-tillage farming preserves 169 kilograms of carbon per hectare per year more than traditional tillage.

The obstacle to this, more often than not, is knowledge. This gap can be filled by the strategic redirection of money from the Future Drought Fund and the Emissions Reduction Fund to support peer-to-peer education schemes for farmers as part of its investment in drought resilience. By strategically deploying some of the money held in these funds, substantial progress could be made in building drought resilience and reducing atmospheric carbon across Australia’s 400 million hectares of farmland.

Government’s biggest contribution, however, will be to increase the hip-pocket incentive to farmers by streamlining and simplifying the application of Australian carbon credit units. Complementing this with cheap and reliable measurement of soil carbon content is the key to rewarding sequestration.

The growing demand for carbon credits from corporations is driving an ad hoc voluntary international carbon trading market, which some Australian farms are already supplying. Last month, in a landmark deal, the Wilmot Cattle Company in New England, NSW, announced the sale of $500,000 worth of soil carbon credits to Microsoft to help it reach its goal of becoming carbon negative by 2030.

Last September, soils were elevated to one of five points in Energy Minister Angus Taylor’s low-emissions technology plan. The plan notes that improving land management practices on just 25 per cent of Australia’s crop and grazing lands could “draw between 35 and 90 million tonnes of CO2 per annum from the atmosphere”.

This idea is timely, and was strengthened by Prime Minister Scott Morrison’s recent commitment to a strong focus on soil health, including soil carbon sequestration and a national soil strategy, in the forthcoming budget.

Government investment in farmer training and soil project development skills where farmers embrace carbon farming without taking land out of production would boost drought resilience and open the way to the monetisation of stored carbon.

With the right incentives and support, farmers can be a big part of the solution to the carbon challenge, not the problem.