A5018427740- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Climate change and permafrost
- Atmospheric chemistry and aerosols
- Polar Research and Ecology
- Atmospheric Ozone and Climate
- Winter Sports Injuries and Performance
- Climate variability and models
- Pleistocene-Era Hominins and Archaeology
- Arctic and Antarctic ice dynamics
- Groundwater and Isotope Geochemistry
- Hydrocarbon exploration and reservoir analysis
- Landslides and related hazards
- Marine and coastal ecosystems
- Spacecraft and Cryogenic Technologies
- Paleontology and Stratigraphy of Fossils
- Astro and Planetary Science
- Oceanographic and Atmospheric Processes
- Marine and environmental studies
- Radioactive contamination and transfer
- Freezing and Crystallization Processes
- Groundwater flow and contamination studies
Scripps Institution of Oceanography
2016-2025
University of California, San Diego
2016-2025
Arizona State University
2016
Oregon State University
2006
Institute of Arctic and Alpine Research
2006
University of Colorado Boulder
2006
National Institute of Water and Atmospheric Research
2006
Lamont-Doherty Earth Observatory
1992-1999
University of Rhode Island
1996-1999
Pennsylvania State University
1999
The last glacial period was terminated by an abrupt warming event in the North Atlantic approximately 15,000 years before present, and events of similar age have been reported from low latitudes. Understanding mechanism this termination requires that precise relative timing climate tropics versus be known. Nitrogen argon isotopes trapped air Greenland ice show Summit warmed 9 +/- 3 degrees C over a several decades, beginning 14,672 ago. Atmospheric methane concentrations rose abruptly...
Old and older, cold colder Greenland surface air temperatures changed dramatically during the last deglaciation. The exact amount is unknown, which makes it difficult to understand what caused those changes. Buizert et al. report temperature reconstructions for period from 19,000 10,000 years before present three different locations in interpret them with a climate model (see Perspective by Sime). They provide broad geographic pattern of variability infer mechanisms changes their...
Abstract. The West Antarctic Ice Sheet Divide (WAIS Divide, WD) ice core is a newly drilled, high-accumulation deep that provides climate records of the past ∼68 ka at unprecedented temporal resolution. upper 2850 m (back to 31.2 BP) have been dated using annual-layer counting. Here we present chronology for part (67.8–31.2 BP), which based on stratigraphic matching annual-layer-counted Greenland cores globally well-mixed atmospheric methane. We calculate WD gas age–ice age difference (Δage)...
Abstract. A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring annual layer counted Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from NGRIP to NEEM using 787 match points of mainly volcanic origin identified in electrical conductivity measurement (ECM) dielectrical profiling (DEP) records. Tephra horizons found both cores are used test matching based on ECM DEP provide five additional timescale...
Antarctic paleotemperatures It has been widely thought that East Antarctica was ∼9°C cooler during the Last Glacial Maximum, close to ∼10°C difference between then and now determined independently for West Antarctica. Buizert et al. used borehole thermometry, firn density reconstructions, climate modeling show temperature in actually only ∼4° 7°C Maximum. This result important consequences our understanding of climate, polar amplification, global change. Science , abd2897, this issue p. 1097
Significance The Younger Dryas (YD) was an ∼1,300-y period of extreme climate that dramatically reversed the course global warming brought last Ice Age to a close. Understanding what mechanisms triggered and terminated this event remains enigmatic, but it is fundamental for gaining insights into inner workings Earth’s system. In study, we used combination well-dated speleothem ice-core records pinpoint timing its onsets terminations in various climatic regimes around world. We show YD...
The causal mechanisms responsible for the abrupt climate changes of Last Glacial Period remain unclear. One major difficulty is dating ice-rafted debris deposits associated with Heinrich events: Extensive iceberg influxes into North Atlantic Ocean linked to global impacts on and biogeochemistry. In a new ice core record atmospheric methane ultrahigh temporal resolution, we find increases within stadials 1, 2, 4, 5 that, uniquely, have no counterparts in Greenland temperature proxies. Using...
The most recent glacial to interglacial transition constitutes a remarkable natural experiment for learning how Earth's climate responds various forcings, including rise in atmospheric CO2 This has left direct thermal remnant the polar ice sheets, where exceptional purity and continual accumulation of permit analyses not possible other settings. For Antarctica, deglacial warming previously been constrained only by water isotopic composition cores, without an absolute thermometric assessment...
An understanding of the mechanisms that control CO2 change during glacial-interglacial cycles remains elusive. Here we help to constrain changing sources with a high-precision, high-resolution deglacial record stable isotopic composition carbon in CO2(δ(13)C-CO2) air extracted from ice samples Taylor Glacier, Antarctica. During initial rise atmospheric 17.6 15.5 ka, these data demarcate decrease δ(13)C-CO2, likely due weakened oceanic biological pump. From 11.5 continued 40 ppm is associated...
The analysis of air bubbles from ice cores has yielded a precise record atmospheric greenhouse gas concentrations, but the timing changes in these gases with respect to temperature is not accurately known because uncertainty age-ice age difference. We have measured isotopic composition argon Vostok core during Termination III (approximately 240,000 years before present). This most likely reflects and accumulation change, although mechanism remains unclear. sequence events suggests that CO2...
Photosynthesis and respiration occur widely on Earth's surface, the 18O/16O ratio of oxygen produced consumed varies with climatic conditions. As a consequence, history climate is reflected in deviation air (delta18Oatm) from seawater delta18O (known as Dole effect). We report variations delta18Oatm over past 60,000 years related to Heinrich Dansgaard-Oeschger events, two modes abrupt change observed during last ice age. Correlations cave records support hypothesis that effect primarily...
Abstract. The recovery of a 1.5 million yr long ice core from Antarctica represents keystone our understanding Quaternary climate, the progression glaciation over this time period and role greenhouse gas cycles in progression. Here we tackle question where such may still be found Antarctic sheet. We can show that old is most likely to exist plateau area East sheet (EAIS) without stratigraphic disturbance should able recovered after careful pre-site selection studies. Based on simple heat...
Abstract. Air was sampled from the porous firn layer at NEEM site in Northern Greenland. We use an ensemble of ten reference tracers known atmospheric history to characterise transport properties site. By analysing uncertainties both data and gas histories, we can objectively assign weights each gases used for depth-diffusivity reconstruction. define objective root mean square criterion that is minimised model tuning procedure. Each tracer constrains profile differently through its unique...
[1] Greenland recently incurred record high temperatures and ice loss by melting, adding to concerns that anthropogenic warming is impacting the Greenland sheet in turn accelerating global sea-level rise. Yet, it remains imprecisely known for how much caused increasing atmospheric greenhouse gases versus natural variability. To address this need, we reconstruct surface snow temperature variability over past 4000 years at GISP2 site (near Summit of sheet; hereafter referred as temperature)...