Jeremy D. Shakun

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We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in(More)
Stalagmite M1-5 from Socotra Island, Yemen in the northwest Indian Ocean provides a robust, high-resolution paleoclimate record from ∼27.4–11.1 ka based on 717 stable isotope and 28 Th measurements. Variations in M1-5 oxygen isotope ratios (δO) are interpreted to be primarily driven by an amount effect related to changes in the mean position and/or(More)
The covariation of carbon dioxide (CO(2)) concentration and temperature in Antarctic ice-core records suggests a close link between CO(2) and climate during the Pleistocene ice ages. The role and relative importance of CO(2) in producing these climate changes remains unclear, however, in part because the ice-core deuterium record reflects local rather than(More)
Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time. Here we provide a broader perspective by reconstructing regional and global temperature anomalies for the past 11,300 years from 73 globally distributed records. Early Holocene (10,000 to 5000 years ago) warmth is followed by ~0.7°C cooling(More)
The UVic Earth System Climate Model (version 2.8 with parameters as described in detail in (28)) includes a three-dimensional ocean general circulation model, a dynamicthermodynamic sea ice model, a simple one-layer energy-moisture balance model of the atmosphere as well as land-surface and dynamic terrestrial vegetation components at a resolution of(More)
Cosmogenic surface-exposure 10Be dating of Last Glacial Maximum (LGM) moraines indicates that glaciers in the southwestern Uinta Mountains remained at their maximum positions until ca. 16.8 0.7 ka, 2 k.y. after glaciers in the neighboring Wind River Range and Colorado Rockies began to retreat. The timing of the local LGM in the southwestern Uintas overlaps(More)
Assessing the impact of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 kelvin (K) as the best estimate, 2 to 4.5 K as the 66% probability range, and nonzero probabilities for much higher values, the latter(More)
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of ice sheets caused global mean sea(More)
While the abrupt climate events of the last deglaciation are well defined in ice core records from the polar regions of both hemispheres, their manifestation elsewhere is less well constrained. Here we compile 104 high-resolution paleoclimate records to characterize the timing and spatial pattern of climate change during the last deglaciation. This(More)