Constraining climate forecasts: The role of prior assumptions
Constraining climate forecasts: The role of prior assumptions
复制标题
限制气候预测：先验假设的作用
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Allen
中科院分区：
文献类型：
--
作者：
D. Frame;B. Booth;J. Kettleborough;D. Stainforth;J. Gregory;M. Collins;M. Allen
任何利用观测估计气候敏感性的尝试都需要一套模式或模式版本，在给定一系列未知气候系统属性值的情况下，同时预测气候敏感性和某些可观测量（‐ies），这些未知气候系统属性值由参数、子系统甚至整个模式的选择表示。研究人员对这些未知属性所做的选择在调节他们的气候预测中起着至关重要的作用。我们表明，对气候敏感性的任何概率估计，以及因此对给定温室气体稳定水平可能导致“危险的”平衡变暖的风险的任何概率估计，都严重依赖于研究人员的主观先验假设，而不仅仅依赖于实际气候观测提供的约束。这种明显的任意性可以通过关注预测的预期目的来解决：虽然长期平衡变暖的不确定性仍然很高，但在几乎所有当前排放情景下，与21世纪短暂变暖预测相关的气候敏感性的10-90%（5-95%）的客观确定不确定性范围为1.4-4.1°C，中值为2.4°C，与“传统”范围很好地吻合。
Any attempt to estimate climate sensitivity using observations requires a set of models or model‐versions that simultaneously predict both climate sensitivity and some observable quantity(‐ies) given a range of values of unknown climate system properties, represented by choices of parameters, subsystems or even entire models. The choices researchers make with respect to these unknown properties play a crucial role in conditioning their climate forecasts. We show that any probabilistic estimate of climate sensitivity, and hence of the risk that a given greenhouse gas stabilisation level might result in a “dangerous” equilibrium warming, is critically dependent on subjective prior assumptions of the investigators, not simply on constraints provided by actual climate observations. This apparent arbitrariness can be resolved by focussing on the intended purpose of the forecast: while uncertainty in long‐term equilibrium warming remains high, an objectively determined 10–90% (5–95%) range of uncertainty in climate sensitivity that is relevant to forecasts of 21st century transient warming under nearly all current emission scenarios is 1.4–4.1°C with a median of 2.4°C, in good agreement with the “traditional” range.