Understanding the change in soil organic carbon (C) stock in a warmer climate and the effect of current land management on that stock is critical for soil and environmental conservation and climate policy. By simulation modeling, we predicted changes in Australia’s soil organic C stock from 2010 to 2100. These vary from losses of 0.014–0.077 t C ha⁻¹ year⁻¹ between 2020 and 2045 and 0.013–0.047 t C ha⁻¹ year⁻¹ between 2070 and 2100, under increasing emissions of greenhouse gases and temperature. Thus, Australian soil will be a net emitter of CO₂. Depending on the future socio-economic conditions, we predict that croplands will accrue as much as 0.19 t C ha⁻¹ year⁻¹ between 2020 and 2045 due to their management, but accrual will decrease with warming and increased emissions by 2070–2100. The gains will be too small to counteract the losses of C from the larger areas of rangelands and coastal regions that are more sensitive to a warmer climate. In principle, prudent management of the rangelands, for example, improving grazing management and regenerating biodiverse, endemic native plant communities, could sequester more C and mitigate the loss; in practice, it may be more difficult, requiring innovation, interdisciplinary science, cultural awareness and effective policies.

了解气候变暖时土壤有机碳 (C) 储量的变化以及当前土地管理对该储量的影响对于土壤和环境保护以及气候政策至关重要。通过模拟建模，我们预测了 2010 年至 2100 年澳大利亚土壤有机碳储量的变化。这些变化从 2020 年至 2045 年期间的 0.014–0.077 t C ha ^{−1year −1}损失和 0.013–0.047 t C ha ^{−1year −1}损失不等。 2070年至2100年间，温室气体排放量和气温不断增加。因此，澳大利亚土壤将成为CO ₂的净排放者。根据未来的社会经济条件，我们预测，由于管理，农田在 2020 年至 2045 年间将累积多达 0.19 t C ha −1year ^{− 1}，但到 2070 年至 2100 年，累积量将随着变暖和排放量的增加而减少。这些收益太小，无法抵消对气候变暖更敏感的大面积牧场和沿海地区的碳损失。原则上，对牧场的审慎管理，例如改善放牧管理和再生生物多样性、特有的本地植物群落，可以封存更多的碳并减少损失；在实践中，这可能更加困难，需要创新、跨学科科学、文化意识和有效的政策。