Recent analysis of 38 globally distributed paleoclimatic records covering Marine Isotope Stage 3 (MIS 3) 60–26 ka demonstrated that the two leading empirical orthogonal functions (EOFs) explaining the data are the Greenland ice-core signal (“northern” signal) and the Antarctic ice-core signal (“southern” signal). Here singular spectral analysis (SSA) is used...
The ongoing retreat of glaciers globally is one of the clearest manifestations of recent global warming associated with rising greenhouse gas concentrations. By comparison, the importance of greenhouse gases in driving glacier retreat during the most recent deglaciation, the last major interval of global warming, is unclear due to uncertainties...
The ongoing retreat of glaciers globally is one of the clearest manifestations of recent global warming associated with rising greenhouse gas concentrations. By comparison, the importance of greenhouse gases in driving glacier retreat during the most recent deglaciation, the last major interval of global warming, is unclear due to uncertainties...
The ongoing retreat of glaciers globally is one of the clearest manifestations of recent global warming associated with rising greenhouse gas concentrations. By comparison, the importance of greenhouse gases in driving glacier retreat during the most recent deglaciation, the last major interval of global warming, is unclear due to uncertainties...
The last deglaciation of the Scandinavian Ice Sheet (SIS) from ∼21,000 to 13,000 yr ago is well-constrained by several hundred ¹⁰Be and ¹⁴C ages. The subsequent retreat history, however, is established primarily from minimum-limiting ¹⁴C ages and incomplete Baltic-Sea varve records, leaving a substantial fraction of final SIS retreat history...
The last deglaciation of the Scandinavian Ice Sheet (SIS) from ∼21,000 to 13,000 yr ago is well-constrained by several hundred ¹⁰Be and ¹⁴C ages. The subsequent retreat history, however, is established primarily from minimum-limiting ¹⁴C ages and incomplete Baltic-Sea varve records, leaving a substantial fraction of final SIS retreat history...
The last deglaciation of the Scandinavian Ice Sheet (SIS) from ∼21,000 to 13,000 yr ago is well-constrained by several hundred ¹⁰Be and ¹⁴C ages. The subsequent retreat history, however, is established primarily from minimum-limiting ¹⁴C ages and incomplete Baltic-Sea varve records, leaving a substantial fraction of final SIS retreat history...
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
Assessing impacts 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 K as best estimate, 2–4.5 K as the 66% probability range, and non-zero probabilities for much higher values, the latter implying a...
Assessing impacts 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 K as best estimate, 2–4.5 K as the 66% probability range, and non-zero probabilities for much higher values, the latter implying a...
The last deglaciation of the Scandinavian Ice Sheet (SIS) from ∼21,000 to 13,000 yr ago is well-constrained by several hundred ¹⁰Be and ¹⁴C ages. The subsequent retreat history, however, is established primarily from minimum-limiting ¹⁴C ages and incomplete Baltic-Sea varve records, leaving a substantial fraction of final SIS retreat history...
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
The ongoing retreat of glaciers globally is one of the clearest manifestations of recent global warming associated with rising greenhouse gas concentrations. By comparison, the importance of greenhouse gases in driving glacier retreat during the most recent deglaciation, the last major interval of global warming, is unclear due to uncertainties...
Assessing impacts 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 K as best estimate, 2–4.5 K as the 66% probability range, and non-zero probabilities for much higher values, the latter implying a...
We review and synthesize the geologic record that
constrains the sources of sea level rise and freshwater discharge
to the global oceans associated with retreat of ice
sheets during the last deglaciation. The Last Glacial Maximum
(~26–19 ka) was terminated by a rapid 5–10 m sea
level rise at 19.0–19.5...
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...
We summarize 121 ¹⁴C and in-situ cosmogenic (¹⁰Be and ³⁶Cl) ages that constrain fluctuations of the Irish Ice Sheet (IIS) since the Last Glacial Maximum (LGM) that can be linked to abrupt climate changes in the North Atlantic region. These data provide a robust means to date ice-sheet fluctuations because...
We investigate the stability of marine ice sheets by coupling a gravitationally self-consistent sea level model valid for a self-gravitating, viscoelastically deforming Earth to a 1-D marine ice sheet-shelf model. The evolution of the coupled model is explored for a suite of simulations in which we vary the bed slope...
We simulate three-dimensional ice temperature fields to examine spatial-temporal history of the subglacial thermal environment during the last glacial cycle. Model results suggest that 60–80% of the Laurentide Ice Sheet was cold-based (frozen to the bed) at the LGM, and therefore unable to undergo large-scale basal flow. The fraction of...
The last deglaciation was interrupted by three major cooling events, the Younger Dryas, the Preboreal Oscillation and the 8.2-ka cold event. As the Laurentide Ice Sheet retreated, different outlets from Lake Agassiz became available causing the proglacial lake to drain to a new level in a rather short timescale (flood)...
Retreat of the Laurentide Ice Sheet (LIS) following the Last Glacial Maximum 21 000 yr BP affected regional to global climate and accounted for the largest proportion of sea level rise. Although the late Pleistocene LIS retreat chronology is relatively well constrained, its Holocene chronology remains poorly dated, limiting our...
The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ≈12.9 to 11.5 kiloyears B.P. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St....
We examine the relation between δ¹⁸O in rainwater collected in southwestern Oregon
and climate variables including temperature, parcel trajectory, precipitation amount, and
specific humidity. Local surface air temperature at the time of sample collection explains a
large proportion of δ¹⁸O variability, suggesting that paleoclimatic archives that are related
to rainfall...
Glacial sedimentary sequences in the north central United States record multiple advances of the
Laurentide Ice Sheet (LIS) since ~2 Ma. Although the tills found in these sequences were deposited by
southward flowing glacial lobes, little information is available on the geometry of flow lines in the interior
of the...