Purpose of Review

Here, we review recent estimates of the remaining carbon budget, with a focus on characterizing key uncertainties and assessing the implications for net-zero CO₂ targets and climate policy.

Recent Findings

Recent analyses offer a range estimates of remaining allowable CO₂ emissions for the 1.5 °C and well-below 2 °C climate targets, though the treatment and coverage of key sources of uncertainty vary considerably among studies. We recommend that net-zero CO₂ targets be set with explicit recognition of the uncertainty associated with carbon budget estimates and be updated regularly as this uncertainty is better constrained. Allocating the remaining carbon budget among countries or other entities, as well as monitoring progress at the subnational level, represents additional key challenges in applying a carbon budget framework to climate policy.

Summary

Despite these challenges, recent advances in quantifying carbon budget uncertainty demonstrate that the concept is well-suited to inform climate policy and to evaluate whether net-zero CO₂ targets are consistent with the goals of the Paris Agreement.

中文翻译：

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剩余碳预算和净零二氧化碳目标在气候减缓政策中的作用

审查目的

在这里，我们回顾了最近对剩余碳预算的估计，重点是描述关键的不确定性并评估对净零CO ₂目标和气候政策的影响。

最近的发现

最近的分析提供了1.5 °C 和远低于 2 °C 气候目标的剩余允许 CO ₂排放量的范围估计，尽管不同研究对关键不确定性来源的处理和覆盖范围差异很大。我们建议在明确认识到与碳预算估算相关的不确定性的情况下设定净零CO ₂ 目标，并定期更新，因为这种不确定性得到了更好的限制。在国家或其他实体之间分配剩余的碳预算，以及监测国家以下各级的进展情况，是将碳预算框架应用于气候政策的额外关键挑战。

概括

尽管存在这些挑战，量化碳预算不确定性的最新进展表明，该概念非常适合为气候政策提供信息，并评估净零CO ₂目标是否与《巴黎协定》的目标一致。