Soil in Australia could start emitting more carbon than it absorbs, scientists warn

The soil in Australia could become one of the sources of carbon emission instead of soaking the harmful gas as early as in the next two decades, a new study warned.

Soil helps keep the Earth cooler by absorbing more carbon than it emits, which is why it is considered a carbon sink.

But as the climate gets warmer, the soil’s ability to retain carbon decreases, and in some instances it can start to release some carbon back into the air, exacerbating the global climate crisis.

A recent paper published in the journal NPJ shows that soil in Australia could become a carbon emitter as early as in the next two decades, contributing to about 8.3 per cent of the total carbon pollution, even under the most “sustainable” scenario.

The study, carried out by scientists from Curtin University, employed various scenarios to predict the trajectory of this change in Australia.

In a scenario where the world continues to pump out carbon pollution as it does, the soil would emit more than 14 per cent of the carbon by 2045.

Australian soil holds an estimated 28 gigatons of carbon, 70 per cent of which is stored in its vast rangelands.

One of the biggest reasons for this change is farming practices and the heightened sensitivity of certain Australian regions, such as coastal areas and rangelands, to rising temperatures, researchers say.

While some of these areas could continue to store carbon, the study found it would not be enough to offset the amounts of carbon lost from the soil in areas which are more sensitive to warmer weather.

“Unless farming methods are further improved so farmland soils can continue to store carbon, any gains and benefits will likely decrease by 2045 and worsen in time if the Earth continues to warm at its current rate,” professor Raphael Viscarra Rossel, who led the research team, said.

“This means Australia’s soil could release even more carbon into the air instead of storing it, which will in turn make climate change worse.”

“If emissions continue at the current rate, the Earth’s temperature is expected to reach 2 degrees above pre-industrial temperatures sometime this century, which is predicted to have dire consequences and potentially catastrophic impacts for the planet.”

However, amidst these dire projections, the study offers some solutions which could possibly mitigate the adverse effects of soil carbon loss.

Techniques such as improved grazing management, controlled burning, and promoting the growth of native vegetation could enhance soil carbon sequestration, thereby helping to combat climate change.

“Ensuring Australia’s rangeland soils can maintain their carbon stocks is imperative: capturing and storing additional carbon will require interdisciplinary science, innovation, cultural awareness, and effective policies,” says professor Rossel.