HR: 15:20h
AN: B33F-07    [Abstracts]
TI: The Role of Deforestation in the Collapse of Classic Maya Civilization: Lessons for the Current Land Use Management in Northern Mesoamerica
AU: * Ray, D K
EM: deepak.ray@nsstc.uah.edu
AF: Department of Atmospheric Sciences, University of Alabama, Huntsville, 320 Sparkman Drive, NSSTC, Huntsville, AL 35805 United States
AU: Nair, U S
EM: nair@nsstc.uah.edu
AF: Department of Atmospheric Sciences, University of Alabama, Huntsville, 320 Sparkman Drive, NSSTC, Huntsville, AL 35805 United States
AU: Welch, R M
EM: welch@nsstc.uah.edu
AF: Department of Atmospheric Sciences, University of Alabama, Huntsville, 320 Sparkman Drive, NSSTC, Huntsville, AL 35805 United States
AU: Lawton, R O
EM: lawtonr@email.uah.edu
AF: Department of Biological Sciences, University of Alabama, Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 United States
AU: Oglesby, R J
EM: Robert.J.Oglesby@nasa.gov
AF: Department of Atmospheric Sciences, University of Alabama, Huntsville, 320 Sparkman Drive, NSSTC, Huntsville, AL 35805 United States
AU: Pielke, R A
EM: pielke@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, Fort Collins, CO 80523-1371 United States
AU: Sever, T A
EM: tom.sever@msfc.nasa.gov
AF: NASA/NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 United States
AU: Irwin, D
EM: daniel.irwin@nasa.gov
AF: NASA/NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 United States
AB: The classic Maya civilization produced thriving cities that attained population densities comparable to modern day cities during the zenith of its growth approximately around 750 A.D. The Mayan civilization then experienced a catastrophic collapse between 750-950 A.D. Among the various hypothesis forwarded to explain the sudden collapse, one that has recently attracted attention, is the role of deforestation and decreases of regional rainfall that could have affected the day-to-day lives of the ancient Mayas. Deep-rooted rainforest vegetation has access to water stored in deep soil layers, and this deep water is made available to the hydrological cycle through transpiration. Removal of rainforests for agricultural purposes, which is accompanied by soil compaction and reduction in the organic material at the surface, leads to increased runoff and decreased soil water storage. Shallow-rooted vegetation that replaces the deep-rooted rainforests cannot efficiently access the moisture in the deep soil layers, reducing flux of water vapor to the atmosphere. In this study the Colorado State University Regional Atmospheric Modeling System (CSU RAMS) is utilized to examine differences in precipitation between current and forested conditions and between current and deforested conditions similar to those that archaeologists believe were prevalent prior to the collapse. Moreover, current deforestation rates in this region is converting the landscape into one that is similar to those prior to the Maya collapse. The simulated rainfall is compared against climatological rain gauge rainfall values. The statistical scores such as probability of detection, false alarm ratio, and the threat scores all compare favorably with those reported in the literature. Our results suggest that with the removal of forests the rainfall can be expected to decrease by 10 to 100mm in the Maya lowlands. Averaged over the entire Maya lowlands region, dry season rainfall for the forested conditions is 143.3mm compared to 142.7 mm for current conditions (a negligible decrease of 0.4% over the forested scenario). However, domain averaged dry season rainfall in the Maya lowlands decreases to 128.9mm for the deforested scenario, a decrease in 9.7% over current conditions. The model simulations suggest that to-date deforestation has played an insignificant role in creating drier conditions in the Mayan lowlands, except in the regions in northern Guatemala and adjacent Mexico. However, continued deforestation that would be representative of those prior to the collapse of the Maya civilization in the region can be expected to lead to additional decreases in dry season precipitation throughout the entire region by about 10mm to 100mm. Improper land use management in this region could lead to futures catastrophes for the modern humans similar
DE: 1610 Atmosphere (0315, 0325)
DE: 1833 Hydroclimatology
DE: 1834 Human impacts
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
SC: Biogeosciences [B]
MN: Fall Meeting 2005