Southeast Australia experienced intensive and geographically extensive wildfires during the 2019–2020 summer season^1,2. The fires released substantial amounts of carbon dioxide into the atmosphere³. However, existing emission estimates based on fire inventories are uncertain⁴, and vary by up to a factor of four for this event. Here we constrain emission estimates with the help of satellite observations of carbon monoxide⁵, an analytical Bayesian inversion⁶ and observed ratios between emitted carbon dioxide and carbon monoxide⁷. We estimate emissions of carbon dioxide to be 715 teragrams (range 517–867) from November 2019 to January 2020. This is more than twice the estimate derived by five different fire inventories^8,9,10,11,12, and broadly consistent with estimates based on a bottom-up bootstrap analysis of this fire episode¹³. Although fires occur regularly in the savannas in northern Australia, the recent episodes were extremely large in scale and intensity, burning unusually large areas of eucalyptus forest in the southeast¹³. The fires were driven partly by climate change^14,15, making better-constrained emission estimates particularly important. This is because the build-up of atmospheric carbon dioxide may become increasingly dependent on fire-driven climate–carbon feedbacks, as highlighted by this event¹⁶.

^{在 2019-2020 年夏季1,2}期间，澳大利亚东南部经历了密集且地理范围广泛的野火。大火将大量二氧化碳释放到大气中³。然而，基于火灾清单的现有排放估计值是不确定的⁴，并且对于该事件的变化高达四倍。在这里，我们借助卫星观测一氧化碳⁵、贝叶斯分析反演⁶以及观测到的排放二氧化碳和一氧化碳之间的比率^{7来限制排放估计。}. 我们估计，从 2019 年 11 月到 2020 年 1 月，二氧化碳的排放量为 715 太克（范围 517-867）。这是五种不同火灾清单^{8、9、10、11、12}得出的估计值的两倍多，并且与基于对此次火灾事件的自下而上引导分析的估计值¹³。尽管澳大利亚北部的热带草原经常发生火灾，但最近的火灾规模和强度都非常大，烧毁了东南部异常大面积的桉树林¹³。火灾的部分原因是气候变化^14,15，使更好的约束排放估算特别重要。这是因为大气中二氧化碳的积累可能越来越依赖于火灾驱动的气候-碳反馈，正如本次事件所强调的¹⁶。