Model falsifiability and climate slow modes

• Published in: Physica A Vol. 502; pp. 554 - 562
• Main Authors: Essex, Christopher, Tsonis, Anastasios A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2018
• Subjects: Climate complexity; Computational over-stabilization; Computer errors; Dynamical and thermodynamical sensitivity; Slow climate modes; Computer errors; Slow climate modes; Dynamical and thermodynamical sensitivity; Climate complexity; Computational over-stabilization
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2018.02.090

The most advanced climate models are actually modified meteorological models attempting to capture climate in meteorological terms. This seems a straightforward matter of raw computing power applied to large enough sources of current data. Some believe that models have succeeded in capturing climate in this manner. But have they? This paper outlines difficulties with this picture that derive from the finite representation of our computers, and the fundamental unavailability of future data instead. It suggests that alternative windows onto the multi-decadal timescales are necessary in order to overcome the issues raised for practical problems of prediction. •Climate models do not and cannot employ known physics fully. Thus, they are falsified, a priori.•Incomplete physics and the finite representation of computers can induce false instabilities.•Eliminating instability can lead to computational overstabilization or false stability.•Models on ultra-long timescales are dubiously stable. This is referred to as the “climate state.” Is it real?•Decadal variability is understandable in terms of a specific class of nonlinear dynamical systems.