Distinguished Professor Seminar Series: Professor Gifford Miller
Å·ÃÀ¿Ú±¬ÊÓƵ the Event
An Arctic Perspective on Contemporary WarmingÌý
 Giff Miller on the Barnes Ice Cap* |
Join us forÌýourÌýDistinguished Faculty series presentationÌýfeaturing theÌýdistinguished professor of Geological Sciences and Associate Director of the Institute of Arctic and Alpine Research,ÌýGifford Miller, PhD.Ìý
Earth is warming, but the Arctic is warming 2 to 3 times faster than the planetary average. As a result, Arctic land ice is receding, sea ice is decreasing in all seasons, and permafrost is thawing. However, the extent to which recent Arctic warming has been anomalous with respect to long-term natural climate variability remains uncertain. We capitalize on the link between glacier size and summer air temperature to derive a millennial perspective on summer warming. Many ice caps in the Canadian Arctic are frozen to their bed, so instead of eroding, they are ideal preservation agents, and as they recede under warming summers, they expose tundra plants that have been entombed for hundreds to thousands of years. The radiocarbon ages of ice-entombed plants tell us when summers were as warm as present at each site.Ìý
Radiocarbon dates on rooted tundra plants revealed by receding cold-based ice caps in the eastern Canadian Arctic show that 5000 years of natural summertime cooling tied to regular variations in Earth’s orbit has been reversed by anthropogenic increases in greenhouse gases. Arctic summer temperatures of the last 100 years are higher than any century in more than 50 thousand years, including the peak warmth of the early Holocene when orbital variations resulted in high-latitude summer insolation 9% greater than present. Although few people live in the Arctic, the consequences of a warming Arctic have direct consequences on mid-latitudes where most of the world lives.
Å·ÃÀ¿Ú±¬ÊÓƵ the Speaker
Gifford Miller, PhD, distinguished professor of geological sciences and associate director of the Institute of Arctic and Alpine Research.
Professor Miller studies the recent history of Earth to understand the coupled ocean/atmosphere/ice climate systems. He is an internationally renownedÌýauthority on the earth during the Quaternary, the period that began approximately 2.6 million years ago. Specifically, he has tackled important questions regarding paleoclimate in the period and his work has transformed our understanding of why significant flora and fauna changes occurred during the period. A member of the Å·ÃÀ¿Ú±¬ÊÓƵ Boulder faculty since 1980, Miller has a golden touch for finding and choosing important problems to study and is equally legendary for solving problems using unconventional approaches.
In recent years he has focused on providing a millennial perspective on modern warming, especially across the Arctic.
Two important questions he has answered in his fieldwork are: During the Quaternary period, how big was the Arctic ice sheet? And how fast did it change? These issues, as well as several other investigations involving megafauna extinctions, have had major practical implications for his field.
*Gilbert, A., Flowers, G. E., Gifford H. Miller, Refsnider, K. A., Young, N. E., Radic, V. 2017: The projected demise of Barnes Ice Cap: Evidence of an unusually warm 21st century Arctic. Geophysical Research Letters, 44(6): 2810-2816. DOI: 10.1002/2016GL072394
Ìý
Additional Resources
Å·ÃÀ¿Ú±¬ÊÓƵ the Series
The Å·ÃÀ¿Ú±¬ÊÓƵ Boulder Retired Faculty Association (UCBRFA) presents the distinguished professors of the University of Å·ÃÀ¿Ú±¬ÊÓƵ, aÌýlecture and presentation series featuring some of our finest professors andÌýtheir extraordinary research and scholarly work.