Late Pleistocene tropical Pacific temperature sensitivity to radiative greenhouse gas forcing
Kelsey A. Dyez (corresponding) and A. Christina Ravelo, Dept. of Earth and Planetary Sciences, University of CaliforniaSanta Cruz, Santa Cruz, California 95064, USA. Posted online 19 October 2012; doi: 10.1130/G33425.1.
Understanding how global temperature changes with increasing atmospheric greenhouse gas concentrations, or climate sensitivity, is of central importance to climate change research. Climate models provide sensitivity estimates that may not fully incorporate slow, long-term feedbacks such as those involving ice sheets and vegetation. Geological studies, on the other hand, can provide estimates that integrate long- and short-term climate feedbacks to radiative forcing. This study by Kelsey Dyez and Christina Ravelo reveals results that suggest that models may not yet adequately represent the long-term feedbacks related to ocean circulation, vegetation, and associated dust, or the cryosphere, and/or may underestimate the effects of tropical clouds or other short-term feedback processes.
Grounding-line retreat of the West Antarctic Ice Sheet from inner Pine Island Bay
Claus-Dieter Hillenbrand et al., British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK. Posted online 19 October 2012; doi: 10.1130/G33469.1.
Over the last few decades, melting of West Antarctic glaciers has contributed significantly to global sea-level rise. Since 1992, two major outlet glaciers have experienced up to 25 km of landward retreat of their "grounding line," the position at which the glacier margin starts to float. Both glaciers rest on a bed far below sea level, so their grounding line may undergo further rapid retreat over coming decades. Until today, the long-term context of the "snapshot" of ice-sheet history recorded over the last 20 years was poorly understood. This context is cruc
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