Introduction. Pliocene climate, processes and problems

Abstract

Climate predictions produced by numerical climate models, often referred to as general circulation models (GCMs), suggest that by the end of the twenty-first century global mean annual surface air temperatures will increase by 1.1-6.4 degrees C. Trace gas records from ice cores indicate that atmospheric concentrations of CO2 are already higher than at any time during the last 650000 years. In the next 50 years, atmospheric CO2 concentrations are expected to reach a level not encountered since an epoch of time known as the Pliocene. Uniformitarianism is a key principle of geological science, but can the past also be a guide to the future? To what extent does an examination of the Pliocene geological record enable us to successfully understand and interpret this guide? How reliable are the 'retrodictions' of Pliocene climates produced by GCMs and what does this tell us about the accuracy of model predictions for the future? These questions provide the scientific rationale for this Theme Issue.

Tropical cyclone genesis potential across palaeoclimates

“…Meanwhile the equilibrium Pliocene-preindustrial difference in this study shows a general decrease (except for a region of the central North Pacific that has an increase in GPI). The stark difference in GPI response between the RCP8.5 and Pliocene therefore raises additional questions regarding the suitability of the choice of the Pliocene as a projection of modern-day greenhouse climate (Haywood et al, 2009), at least in terms of cyclogenesis-related measures. Held and Zhou (2011) show that TCs respond differently to the direct CO 2 forcing and the resultant temperature changes.…”

“…There is potential of using the Pliocene to learn about the Published by Copernicus Publications on behalf of the European Geosciences Union. equilibrium state of Earth's warm climate following anthropogenic greenhouse gas influence (Haywood et al, 2009).…”

Diatom evidence for the onset of Pliocene cooling from AND-1B, McMurdo Sound, Antarctica

“…Designed to constrain global conditions during this warmer-than-present analog interval, PRISM now provides the most comprehensive pre-Quaternary global climate synthesis available (e.g., Dowsett et al, 1999;Haywood and Valdes, 2004 and references therein; Dowsett, 2007;Dowsett et al, 2009;Haywood et al, 2009aHaywood et al, , 2009b. Within this synthesis, insights on Antarctic participation in the Pliocene climate system have largely been filtered through its fingerprint on the Southern Ocean.…”

Biogeography and conservation in Southeast Asia: how 2.7 million years of repeated environmental fluctuations affect today’s patterns and the future of the remaining refugial-phase biodiversity

“…The mid-Pliocene (*3 Ma), when global temperatures were on average 3°C higher, is especially useful as a model of coming vegetation and biome distribution changes (Bonham et al 2009;Haywood et al 2009;Salzmann et al 2008Salzmann et al , 2009. Given that many extant species lived in Southeast Asia during the Pliocene, and have survived multiple glacial/interglacial cycles since then, they will probable be less challenged by temperature than seasonality and the length of the dry season.…”