NSF Org:	OPP Office of Polar Programs (OPP)
Recipient:	THE REGENTS OF THE UNIVERSITY OF COLORADO
Initial Amendment Date:	June 21, 2021
Latest Amendment Date:	March 6, 2025
Award Number:	2100381
Award Instrument:	Standard Grant
Program Manager:	Marc Stieglitz mstiegli@nsf.gov  (703)292-4354 OPP  Office of Polar Programs (OPP) GEO  Directorate for Geosciences
Start Date:	July 15, 2021
End Date:	June 30, 2026 (Estimated)
Total Intended Award Amount:	$62,715.00
Total Awarded Amount to Date:	$75,163.00
Funds Obligated to Date:	FY 2021 = $62,715.00 FY 2025 = $12,448.00
History of Investigator:	Gifford Miller (Principal Investigator) gmiller@colorado.edu
Recipient Sponsored Research Office:	University of Colorado at Boulder 3100 MARINE ST Boulder CO  US  80309-0001 (303)492-6221
Sponsor Congressional District:	02
Primary Place of Performance:	University of Colorado at Boulder 3100 Marine Street, Room 481 572 Boulder CO  US  80301-1058
Primary Place of Performance Congressional District:	02
Unique Entity Identifier (UEI):	SPVKK1RC2MZ3
Parent UEI:
NSF Program(s):	ANS-Arctic Natural Sciences
Primary Program Source:	0100XXXXDB NSF RESEARCH & RELATED ACTIVIT 0100CYXXDB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):	5294, 1079
Program Element Code(s):	528000
Award Agency Code:	4900
Fund Agency Code:	4900
Assistance Listing Number(s):	47.078

ABSTRACT

Miller/Kaufman: Toward placing contemporary Arctic summer warming in a millennial perspective with a pan- Arctic record of Neoglacial crysophere expansion

Non-technical summary. Glacier dimensions in the Arctic are set by summer temperature, but changes in the dimensions of Alaskan glaciers since the end of the ice age are poorly constrained. In response to recent Arctic warming, glaciers in the Brooks Range, Alaska are receding rapidly, and in special settings, on gentle slopes where the ice is thin, glaciers act as preservation agents, rather than erosive agents, preserving intact tiny tundra plants living before the ice expanded over that site in the distant past. The goal of this project is to visit the most likely sites in the Brooks Range where glaciers preserved, rather than eroded the landscape, where we expect tundra plants are being re-exposed as ice recedes. The radiocarbon ages of these plants document when past summers grew colder, allowing ice to expand across these sites, and provide the most reliable
evidence of when in the past Arctic summers cooled enough to allow glaciers to grow.
Broader Impacts. Comparing the ages of ice-entombed Alaska plants to ages of plants exposed in other Arctic regions will allow us to better understand large-scale climate change on a hemispheric scale. These results serve as tests for climate models that are used to predict future climate. The same models used for future projections can be run in reverse to predict climate evolution in the past. If the models predict similar patterns of past climate change as documented by the ages of ice-entombed plants across the Arctic, our confidence in the ability of climate models to reliably predict future climate is increased. If the models fail to predict patterns similar to the plant ages, then it is likely the models have underestimated certain aspects of the climate system.

Technical summary. Changes in the dimensions of Brooks Range glaciers through the Holocene, a primary proxy for changes in summer temperature, are poorly constrained. Where glaciers are cold-based and on gently sloping terrain, they often do not erode, but act as exceptional preservation agents, preserving tiny tundra plants killed by expanding ice. Rapid ice recession across the Brooks Range is now exposing landscapes likely to preserve in situ tundra plants killed by late Holocene ice expansion, with their radiocarbon ages defining episodes of consistently cold summers. This project will visit the most promising sites to look for iceentombed plants emerging as the ice margins recede, and take advantage of the new NSF-supported accelerator mass spectrometer at Northern Arizona University for dating. We expect the resultant composite probability density functions of dated plants to produce age clusters reflecting episodes of ice expansion/cold summers, which can be compared with results from the North Atlantic Arctic, and collectively serve as targets for Common Era climate modeling now underway with CMIP-6.
Broader Impacts. Communicating climate change with the wider public is more important than ever as climate change accelerates and climate literacy lags. Although it's widely understood that glaciers in Alaska (and elsewhere) are rapidly receding, there is less understanding of how unusual this recession really is. This study will place glacier recession in a millennial perspective, likely illustrating that current warming is unprecedented over thousands of years, a concept easily grasped by the general public. To advance public outreach, we will support an experienced graphic designer to translate our science to a form that is accessible to the citizens of Alaska and the broader US community.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Please report errors in award information by writing to: awardsearch@nsf.gov.