A5001132908- Geology and Paleoclimatology Research
- Tree-ring climate responses
- Fire effects on ecosystems
- Climate variability and models
- Species Distribution and Climate Change
- Pleistocene-Era Hominins and Archaeology
- Isotope Analysis in Ecology
- Ecology and Vegetation Dynamics Studies
- Atmospheric and Environmental Gas Dynamics
- Landslides and related hazards
- Climate change and permafrost
- Archaeology and ancient environmental studies
- Cryospheric studies and observations
- Geological formations and processes
- Rangeland and Wildlife Management
- Plant Water Relations and Carbon Dynamics
- Botany, Ecology, and Taxonomy Studies
- Marine and environmental studies
- Hydrology and Watershed Management Studies
- Methane Hydrates and Related Phenomena
- Aeolian processes and effects
- Meteorological Phenomena and Simulations
- Botany and Plant Ecology Studies
- Geological Studies and Exploration
- Peatlands and Wetlands Ecology
University of Oregon
2015-2025
Queensland University of Technology
2024
Rutgers Sexual and Reproductive Health and Rights
2017-2019
New York Proton Center
2018
University of Washington
2008
University of Utah
2008
University of Alaska Fairbanks
1995
Uppsala University
1991
Durham University
1989
Brown University
1984
Subfossil pollen and plant macrofossil data derived from 14C-dated sediment profiles can provide quantitative information on glacial interglacial climates. The allow climate variables related to growing-season warmth, winter cold, plant-available moisture be reconstructed. Continental-scale reconstructions have been made for the mid-Holocene (MH, around 6 ka) Last Glacial Maximum (LGM, 21 ka), allowing comparison with palaeoclimate simulations currently being carried out as part of fifth...
Deciphering the evolution of global climate from end Last Glacial Maximum approximately 19 ka to early Holocene 11 presents an outstanding opportunity for understanding transient response Earth's system external and internal forcings. During this interval warming, decay ice sheets caused mean sea level rise by 80 m; terrestrial marine ecosystems experienced large disturbances range shifts; perturbations carbon cycle resulted in a net release greenhouse gases CO(2) CH(4) atmosphere; changes...
Understanding the causes and consequences of wildfires in forests western United States requires integrated information about fire, climate changes, human activity on multiple temporal scales. We use sedimentary charcoal accumulation rates to construct long-term variations fire during past 3,000 y American West compare this record independent fire-history data from historical records scars. There has been a slight decline burning over y, with lowest levels attained 20th century Little Ice...
This paper integrates recent efforts to map the distribution of biomes for late Quaternary with detailed evidence that plant species have responded individualistically climate change at millennial timescales. Using a fossil‐pollen data set over 700 sites, we review late‐Quaternary vegetation history in northern and eastern North America across levels ecological organization from individual taxa biomes, apply insights gained this critically examine biome maps generated pollen data....
Large variations in the composition, structure, and function of Arctic ecosystems are determined by climatic gradients, especially growing‐season warmth, soil moisture, snow cover. A unified circumpolar classification recognizing five types tundra was developed. The geographic distributions vegetation north 55°N, including position forest limit types, could be predicted from climatology using a small set plant functional embedded biogeochemistry‐biogeography model BIOME4. Several...
Research during the last 20 years has led to a major expansion in knowledge about long-term climatic variability and dynamics. Two developments particular have advanced theoretical understanding of environmental changes that induce continuous ecosystems. The first development was recognition alternation glacial interglacial climates been paced by variations solar radiation generated periodic Earth's orbit. second involved an increased hierarchical controls regional variations. Studies marine...
Maya and Climate has affected the vitality of many different societies in past, as shown by numerous records across globe throughout human history. One most obvious spectacular examples this is from Classic civilization, whose advanced culture left highly detailed all aspects their existence between 300 1000 C.E. Kennett et al. (p. 788 ; see cover) present a climate record derived stalagmite collected cave Belize, midst settlement. The fine resolution precise dating allows changes...
Amplification of the northern hemisphere seasonal cycle insolation during mid‐Holocene causes a northward shift main regions monsoon precipitation over Africa and India in all 18 simulations conducted for Paleoclimate Modeling Intercomparison Project (PMIP). Differences among are related to differences model formulation. Despite qualitative agreement with paleoecological estimates biome shifts, magnitude increases underestimated by models.
Response surfaces describing the empirical dependence of surface pollen percentages 13 taxa on three standard climatic variables (mean July temperature, mean January and annual precipitation) in eastern North America were used to infer past climates from palynological data. Inferred at 3000—yr intervals 18 000 years ago present, based six (spruce, birch, northern pines, oak, southern prairie forbs), generate time series simulated isopoll maps for these seven others (hickory, fir, beech,...
Climate change is predicted to be one of the greatest drivers ecological in coming century. Increases temperature over last century have clearly been linked shifts species distributions. Given magnitude projected future climatic changes, we can expect even larger range These changes will, turn, alter communities and functioning ecosystems. Despite seriousness climate change, uncertainty climate-change projections makes it difficult for conservation managers planners proactively respond...
It is widely accepted, based on data from the last few decades and model simulations, that anthropogenic climate change will cause increased fire activity. However, less attention has been paid to relationship between abrupt changes heightened activity in paleorecord. We use 35 charcoal pollen records assess how regimes North America changed during glacial–interglacial transition (15 10 ka), a time of large rapid changes. also test hypothesis comet impact initiated continental-scale...
High-resolution analysis of macroscopic charcoal in sediment cores from Little Lake was used to reconstruct the fire history last 9000 years. Variations magnetism were examined detect changes allochthonous sedimentation associated with past occurrence. Fire intervals ca. 6850 calendar years BP averaged 110 ± 20 years, when climate warmer and drier than today xerophytic vegetation dominated. From 2750 mean interval lengthened 160 conjunction onset cool humid conditions. Fire-sensitive...
Climate is an important control on biomass burning, but the sensitivity of fire to changes in temperature and moisture balance has not been quantified. We analyze sedimentary charcoal records show that regime over past 21,000 yrs are predictable from regional climates. Analyses paleo‐ data increases monotonically with peaks at intermediate levels, quantitatively most driver burning yrs. Given a similar relationship between climate drivers emerges analyses interannual variability shown by...
Percentages of beech (Fagus L.) pollen in net- implies that the continental-scale patterns works surface samples from Europe and eastern North abundance are equilibrium with modern climatic pat- America reflect present distribution landscape terns on both continents irrespective differences trees continents. migrational history, competitive interactions degree Response surfaces constructed by a locally-weighted human impact. The physiological characteristics determin- averaging technique...