Jennifer Marlon

Holocene fire-histories have been reconstructed from charcoal accumulation rates (CHAR) in lakes, bogs, and forest soils. "Peaks" in the CHAR data represent discrete fire events or intervals with frequent fires, while slowly varying trends represent "background" changes in regional burning, vegetation (biomass), and/or depositional processes. Background CHAR (BCHAR) data were explored in 15 high-resolution macroscopic charcoal records from the northwestern

Particulate charcoal preserved in lake sediments has become an important tool for examining the long-term role of fire as an ecosystem process. The record of microscopic charcoal (100 micron diameter or less) offers information on regional burning patterns, whereas macroscopic particles travel less far and are used to infer local fire history. Reconstruction of past fire activity is based on

DISCCRS: Dissertations Initiative for the Advancement of Climate Change Research; Mesa, Arizona, 13-20 March 2010; Each year, the Dissertations Initiative for the Advancement of Climate Change Research (DISCCRS; http://disccrs.org) brings together a select group of 34 recent Ph.D. graduates to facilitate peer networking and professional development and to encourage interdisciplinary research related to climate change. This year, the invited scholars

Climate change is complex and thus requires interdisciplinary research, and new scholars are rising to that challenge. The Dissertations Initiative for the Advancement of Climate Change Research (DISCCRS (pronounced “discourse”); see http://www.disccrs.org) brings together select groups of recent PhD graduates to encourage interdisciplinary work on climate change. The DISCCRS Symposium VII held just outside of Colorado Springs, Colo., brought together

Holocene fire-histories have been reconstructed from charcoal accumulation rates (CHAR) in lakes, bogs, and forest soils. "Peaks" in the CHAR data represent discrete fire events or intervals with frequent fires, while slowly varying trends represent "background" changes in regional burning, vegetation (biomass), and/or depositional processes. Background CHAR (BCHAR) data were explored in 15 high-resolution macroscopic charcoal records from the northwestern

During the last 20 kyr, fire-history records from the western U.S. and Patagonia display similar patterns and timing despite differences in the large-scale controls of climate between the two hemispheres. In summer-dry areas of northwestern North America, charcoal levels rise after 12 ka and the distribution of charcoal peaks indicates higher-than-present fire frequency until ca. 5-7 ka. High fire occurrence

Particulate charcoal preserved in lake sediments has become an important tool for examining the long-term role of fire as an ecosystem process. The record of microscopic charcoal (100 micron diameter or less) offers information on regional burning patterns, whereas macroscopic particles travel less far and are used to infer local fire history. Reconstruction of past fire activity is based on

Hundreds of late-Quaternary fire-history records have been developed over the past few decades based on charcoal that accumulated in lakes, bogs, and soils, and together provide a coarse-grained, but global depiction of fire since the Last Glacial Maximum (LGM). An international collaborative effort sponsored by the International Geosphere-Biosphere Programme (IGBP) Fast Track Initiative on Fire (FTI) was organized to synthesize

Sedimentary charcoal and pollen records were used to test the hypothesis that an extraterrestrial impact at the beginning of the Younger Dryas Chonozone (YDC, 12.9 to 11.7 ka) caused widespread biomass burning in North America. Comet-theory proponents argue that continental-scale wildfires were triggered by the ET impact and are evidenced by carbon spherules, charcoal and soot found at archaeological sites

Interdisciplinary research is crucial to understanding complex and urgent environmental problems, particularly climate change. Universities are increasingly hosting trans-, multi-, and inter-disciplinary workshops and conferences and developing innovative interdisciplinary training programs (e.g., NSF's IGERT program) to foster such research. Yet, much doctoral training remains highly disciplinary with very little evidence of graduate training producing transformative research that bridges the natural/social-science

ABSTRACT The global charcoal database (GCD) assembled by the Global Palaeofire Working Group (GPWG) over the past several years provides over 800 sedimentary charcoal records of biomass burning that allows wildfire to be examined on a range of spatial and temporal scales. These data, and other analyses of sedimentary charcoal records show that: (1) The data-analytical aspects of sedimentary charcoal have matured to the extent that we can show that biomass burning is well represented by these records, that charcoal influx is a general indicator of area or biomass burning, and that peaks of charcoal influx in records with annual-to-decadal resolution provide evidence of individual fires. (2) The spatial coverage of the records is extensive enough to represent much of the global climate space, although coverage of Africa, Siberia, and grassland and desert ecosystems in general could be improved. (3) The temporal coverage is sufficient to resolve millennial-scale environmental changes over the past glacial cycle, and hemispheric and regional variations in biomass burning from the LGM to present. (4) Global biomass burning was very low at the LGM, and increases in biomass burning into the Holocene tracked hemispheric and regional climate changes. (5) Abrupt climate changes during deglaciation caused specific responses in the charcoal records; these responses are replicated during the abrupt warming and cooling episodes accompanying D-O cycles. (6) During the Holocene, biomass burning reflects regional climate changes and does not support the early anthropocene hypothesis. (7) Over the last millennium, biomass burning also tracks regional climate changes, and shows an unambiguous human influence only over the past 250 years. (8) The variations in global biomass burning on multiple time scales described by the sedimentary charcoal record are supported by the emerging ice core records of biomass burning. (9) Increases in biomass burning are strongly linked to temperature increases on all time scales, and are generally higher at intermediate levels of effective moisture, reflecting a tradeoff between fuel (vegetation productivity) and fire-conducive weather and climate; drought becomes an important control only on decadal and shorter time scales. (10) Human activity is neither necessary nor sufficient for explaining the large-scale, long-term variations in biomass burning.

ABSTRACT Transient simulations of past climate covering several millenia provide an exciting opportunity to study past climate by moving away from the traditional snap-shot approach to paleoclimate modeling. The transient nature of the results requires datasets for comparisons, which can demonstrate changes in past environments over long time periods, and at spatial scales compatible with the grid size of most General Circulation Models (GCMs). The growth of continental, and now global, databases of past environmental sensors (e.g. pollen, plant macrofossils, charcoal) has led to the development of a number of such datasets. These cover a range of different aspects of past terrestrial environments, spatial regions and time periods. We review here existing datasets that are suitable for comparison with the transient experiments, and present some results from a first-order comparison of simulated and reconstructed climate over Northern Hemisphere mid-to-high latitudes for the last 15 000 years. We discuss some issues of data-model comparison in the space and time domain, and outline future directions for this work.