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Event Details 
Science Pop-Up Talks - Dinosaurs to Milankovitch Cycles: Earth’s Climate the Past 250 Million Years
By Dr. Compton Tucker, NASA During the Age of Reptiles, from 250 million years to 66 million years ago, our planet was dominated by the dinosaurs, there was no permanent ice anywhere on the planet, global average air temperatures were 20° F/11° C warmer than today, and the atmospheric CO2 concentration was between 1,000 to 1,500 parts per million. At the same time as the collision of the India plate with the Asia plate starting ~50 million years ago, silicate weathering reduced the atmospheric CO2 concentration from 1,000 to 1,500 ppm to 280 ppm by 2.6 million years ago. At this time, the Milankovitch Cycles, initiated by Earth’s orbital dynamics and enhanced by feedback processes, caused the ice ages with glacial maxima and warmer interglacial periods lasting about 100,000 years and 15,000 years respectively. Human activities have now increased the atmospheric CO2 concentration beyond 410 ppm, where Earth’s orbital dynamics are over-ridden by greenhouse gas forcing. Compton Tucker received his B.S. degree in biological science in 1969, his M.S. degree in 1973, and his Ph.D. degree in 1975, all from Colorado State. As a postdoctoral fellow at NASA/Goddard in 1975-1976, Tucker consolidated two near-infrared bands and adding a second short-wave infrared band to the thematic mapper instruments on Landsat-4 and -5. He was also responsible for making the first and second bands on the Advanced Very High Resolution Radiometer imager discrete, enabling “Normalized difference vegetation index” (NDVI) measurements from polar-orbiting meteorological satellites starting in July of 1981 with NOAA-7. Since becoming a NASA employee in 1977, he has used satellite data for famine early warning, desert locust control, terrestrial primary production, deforestation & land cover mapping, predicting ecologically-coupled disease outbreaks, mapping glacier extent, and mapping climatic effects on global vegetation. From 2002-2012 he was active in NASA’s Space Archaeology Program, leading a NASA team assisting archaeologists mapping ancient sites with ground penetrating radar and magnetometers in Turkey at the sites of Troy, in the Granicus River Valley, and at Gordion, the home of King Midas. Tucker has authored or coauthored more than 190 journal articles that have been cited 60,000 times by Google Scholar, is an adjunct professor at the University of Maryland and a consulting scholar at the University of Pennsylvania’s Museum of Archaeology and Anthropology. He is a Fellow of the American Geophysical Union and the American Association for the Advancement of Science. He has been awarded NASA’s Exceptional Scientific Achievement Medal, the U.S. Geological Survey’s Pecora Award, the National Air and Space Museum Trophy, the Missouri Botanical Garden’s Henry Shaw Medal, the Royal Danish Geographical Society’s Galathea Medal, the Swedish Society of Anthropology and Geography’s Vega Medal, the Mongolian Friendship Medal, and received a Presidential Award for Meritorious Senior Professional Service.
Event Type : Study Groups      
Category : Science Pop-Up Talks -- series 2
Date(s) : 04/22/2021
Day of Week : Thursday
Time : 1:00-2:30
Location : Online
Fee : $10.00
Event Status : COMPLETED