On the Use and Abuse of Climate Sensitivity as a Concept in Paleoclimate. Matt Huber
“Given the nature of the subject we must remind ourselves that it is simply not possible to construct a model…
that can serve as a scaffolding on which….[we] can rely on support at all times….
No matter how versatile the code, the situation will always lead to the consequences
we have already alluded to:….theory conflicts with practice.”
From Clausewitz, (On War, Paret Translation 1989)
After some discussion of the history and application of the concept of climate sensitivity within modern and paleoclimate contexts, I step through a set of case studies in paleoclimate from Eocene through Miocene in which the utility of the concept is assessed. I present results on both greenhouse gas and non-greenhouse gas climate forcings and discuss some of the opportunities and pitfalls associated with thinking within the sensitivity framework. In the end, I conclude with my suggestions, colored as always by my particular perspective, about how to abuse the sensitivity concept less and use it more effectively where appropriate. Sometimes it may need to be abandoned entirely when it has been stretched to the breaking point.
The Climate Dynamics Prediction Laboratory is focused on past, present and future climate, the mechanisms that govern climate, the different forms that climates can take on Earth, and the relationship between climate change and life. Major research areas include the radiative and dynamical processes generating tropical ‘thermostats’, and polar amplification of warming, as well as the ecological and evolutionary implications of these processes and patterns. Most of my work so far has concentrated on the issue of how “stuff” (e.g. passive tracers, water vapor, heat, spores) goes from the tropics toward the Poles, and specifically with an emphasis on how these processes operate during greenhouse climates (e.g. the Eocene ~55-35 mya or the Miocene 23-5 mya ago).