气候学
环境科学
GCM转录因子
强迫(数学)
大气科学
气候模式
气候变化
全球变暖
温室气体
大气环流模式
大气(单位)
地质学
气象学
物理
海洋学
标识
DOI:10.1260/0958-305x.24.3-4.455
摘要
Global surface temperature records (e.g. HadCRUT4) since 1850 are characterized by climatic oscillations synchronous with specific solar, planetary and lunar harmonics superimposed on a background warming modulation. The latter is related to a long millennial solar oscillation and to changes in the chemical composition of the atmosphere (e.g. aerosol and greenhouse gases). However, current general circulation climate models, e.g. the CMIP5 GCMs, to be used in the AR5 IPCC Report in 2013, fail to reconstruct the observed climatic oscillations. As an alternate, an empirical model is proposed that uses: (1) a specific set of decadal, multidecadal, secular and millennial astronomic harmonics to simulate the observed climatic oscillations; (2) a 0.45 attenuation of the GCM ensemble mean simulations to model the anthropogenic and volcano forcing effects. The proposed empirical model outperforms the GCMs by better hind-casting the observed 1850–2012 climatic patterns. It is found that: (1) about 50–60% of the warming observed since 1850 and since 1970 was induced by natural oscillations likely resulting from harmonic astronomical forcings that are not yet included in the GCMs; (2) a 2000–2040 approximately steady projected temperature; (3) a 2000–2100 projected warming ranging between 0.3°C and 1.6° C, which is significantly lower than the IPCC GCM ensemble mean projected warming of 1.1° C to 4.1° C; (4) an equilibrium climate sensitivity to CO 2 doubling centered in 1.35°C and varying between 0.9°C and 2.0°C.
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