[PAOCQ] Sandra Kirtland Turner (UC Riverside)

Feedbacks between the carbon cycle and climate remain a key source of uncertainty in future climate change projections, especially on timescales beyond the next 100 years. The known, cyclic changes in solar insolation driven by orbital variations provide a suite of sensitivity studies for evaluating these feedbacks across the wide range of Cenozoic climate states, from the high CO2 Paleogene ‘greenhouse’ to the Neogene ‘icehouse.’ While understanding how variations in Earth’s orbital geometry impact climate has been a central role of paleoclimatology for decades, there remains a persistent mismatch between empirical and numerical modeling strategies to elucidate these mechanisms. I will describe combined model-data advances to evaluate carbon cycle feedbacks in response to orbital forcing by implementing time-varying orbital forcing of insolation into an intermediate complexity Earth system model. In addition, I will discuss how modeling of extreme climate events, like the Paleocene Eocene Thermal Maximum 56 million years ago, may provide additional insight into the operation of carbon cycle feedbacks in response to more rapid forcing.