Articles | Volume 18, issue 8
https://doi.org/10.5194/tc-18-3591-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/tc-18-3591-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Arctic glacier snowline altitudes rise 150 m over the last 4 decades
Laura J. Larocca
CORRESPONDING AUTHOR
School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
Cooperative Programs for the Advancement of Earth System Science, University Corporation for Atmospheric Research, Boulder, CO 80307, USA
School of Ocean Futures, Arizona State University, Tempe, AZ 85281, USA
James M. Lea
Department of Geography and Planning, University of Liverpool, Liverpool, UK
Michael P. Erb
School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
Nicholas P. McKay
School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
Megan Phillips
School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
Kara A. Lamantia
Byrd Polar and Climate Research Center, Ohio State University, Columbus, OH 43210, USA
School of Earth Sciences, Ohio State University, Columbus, OH 43210, USA
Darrell S. Kaufman
School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
Related authors
Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark
The Cryosphere, 18, 4633–4644, https://doi.org/10.5194/tc-18-4633-2024, https://doi.org/10.5194/tc-18-4633-2024, 2024
Short summary
Short summary
Glaciers that exist within tropical regions are vital water resources and excellent indicators of a changing climate. We use satellite imagery analysis to detect the boundary between snow and ice on the Quelccaya Ice Cap (QIC), Peru, which indicates the ice cap's overall health. These results are analyzed with other variables, such as temperature, precipitation, and sea surface temperature anomalies, to better understand the factors and timelines driving the ice retreat.
Christopher L. Hancock, Michael P. Erb, Nicholas P. McKay, Sylvia G. Dee, and Ruza F. Ivanovic
Clim. Past, 20, 2663–2684, https://doi.org/10.5194/cp-20-2663-2024, https://doi.org/10.5194/cp-20-2663-2024, 2024
Short summary
Short summary
We reconstruct global hydroclimate anomalies for the past 21 000 years using a data assimilation methodology blending observations recorded in lake sediments with the climate dynamics simulated by climate models. The reconstruction resolves data–model disagreement in east Africa and North America, and we find that changing global temperatures and associated circulation patterns, as well as orbital forcing, are the dominant controls on global precipitation over this interval.
Darrell Kaufman and Valérie Masson-Delmotte
Clim. Past, 20, 2587–2594, https://doi.org/10.5194/cp-20-2587-2024, https://doi.org/10.5194/cp-20-2587-2024, 2024
Short summary
Short summary
Rather than reverting to a dedicated paleoclimate chapter, knowledge about pre-industrial climate should be further integrated with other lines of evidence throughout the next assessment reports by the Intergovernmental Panel on Climate Change.
Kara A. Lamantia, Laura J. Larocca, Lonnie G. Thompson, and Bryan G. Mark
The Cryosphere, 18, 4633–4644, https://doi.org/10.5194/tc-18-4633-2024, https://doi.org/10.5194/tc-18-4633-2024, 2024
Short summary
Short summary
Glaciers that exist within tropical regions are vital water resources and excellent indicators of a changing climate. We use satellite imagery analysis to detect the boundary between snow and ice on the Quelccaya Ice Cap (QIC), Peru, which indicates the ice cap's overall health. These results are analyzed with other variables, such as temperature, precipitation, and sea surface temperature anomalies, to better understand the factors and timelines driving the ice retreat.
Gabriel West, Darrell S. Kaufman, Martin Jakobsson, and Matt O'Regan
Geochronology, 5, 285–299, https://doi.org/10.5194/gchron-5-285-2023, https://doi.org/10.5194/gchron-5-285-2023, 2023
Short summary
Short summary
We report aspartic and glutamic acid racemization analyses on Neogloboquadrina pachyderma and Cibicidoides wuellerstorfi from the Arctic Ocean (AO). The rates of racemization in the species are compared. Calibrating the rate of racemization in C. wuellerstorfi for the past 400 ka allows the estimation of sample ages from the central AO. Estimated ages are older than existing age assignments (as previously observed for N. pachyderma), confirming that differences are not due to taxonomic effects.
Michael P. Erb, Nicholas P. McKay, Nathan Steiger, Sylvia Dee, Chris Hancock, Ruza F. Ivanovic, Lauren J. Gregoire, and Paul Valdes
Clim. Past, 18, 2599–2629, https://doi.org/10.5194/cp-18-2599-2022, https://doi.org/10.5194/cp-18-2599-2022, 2022
Short summary
Short summary
To look at climate over the past 12 000 years, we reconstruct spatial temperature using natural climate archives and information from model simulations. Our results show mild global mean warmth around 6000 years ago, which differs somewhat from past reconstructions. Undiagnosed seasonal biases in the data could explain some of the observed temperature change, but this still would not explain the large difference between many reconstructions and climate models over this period.
Sophie Goliber, Taryn Black, Ginny Catania, James M. Lea, Helene Olsen, Daniel Cheng, Suzanne Bevan, Anders Bjørk, Charlie Bunce, Stephen Brough, J. Rachel Carr, Tom Cowton, Alex Gardner, Dominik Fahrner, Emily Hill, Ian Joughin, Niels J. Korsgaard, Adrian Luckman, Twila Moon, Tavi Murray, Andrew Sole, Michael Wood, and Enze Zhang
The Cryosphere, 16, 3215–3233, https://doi.org/10.5194/tc-16-3215-2022, https://doi.org/10.5194/tc-16-3215-2022, 2022
Short summary
Short summary
Terminus traces have been used to understand how Greenland's glaciers have changed over time; however, manual digitization is time-intensive, and a lack of coordination leads to duplication of efforts. We have compiled a dataset of over 39 000 terminus traces for 278 glaciers for scientific and machine learning applications. We also provide an overview of an updated version of the Google Earth Engine Digitization Tool (GEEDiT), which has been developed specifically for the Greenland Ice Sheet.
Darrell S. Kaufman and Nicholas P. McKay
Clim. Past, 18, 911–917, https://doi.org/10.5194/cp-18-911-2022, https://doi.org/10.5194/cp-18-911-2022, 2022
Short summary
Short summary
Global mean surface temperatures are rising to levels unprecedented in over 100 000 years. This conclusion takes into account both recent global warming and likely future warming, which thereby enables a direct comparison with paleotemperature reconstructions on multi-century timescales.
Lauren J. Davies, Britta J. L. Jensen, and Darrell S. Kaufman
Geochronology, 4, 121–141, https://doi.org/10.5194/gchron-4-121-2022, https://doi.org/10.5194/gchron-4-121-2022, 2022
Short summary
Short summary
Subarctic and Arctic lake sediments provide key data to understand natural climate variability and future climate change. However, they can be difficult to date accurately and of limited use without a robust chronology. We use volcanic ash deposits from the last ~4000 BP to identify anomalously old radiocarbon ages at Cascade Lake, Alaska. A provisional ~15 000-year Bayesian age model is produced for the lake, and a new location for ash from five Late Holocene eruptions is reported.
David W. Ashmore, Douglas W. F. Mair, Jonathan E. Higham, Stephen Brough, James M. Lea, and Isabel J. Nias
The Cryosphere, 16, 219–236, https://doi.org/10.5194/tc-16-219-2022, https://doi.org/10.5194/tc-16-219-2022, 2022
Short summary
Short summary
In this paper we explore the use of a transferrable and flexible statistical technique to try and untangle the multiple influences on marine-terminating glacier dynamics, as measured from space. We decompose a satellite-derived ice velocity record into ranked sets of static maps and temporal coefficients. We present evidence that the approach can identify velocity variability mainly driven by changes in terminus position and velocity variation mainly driven by subglacial hydrological processes.
Peter A. Tuckett, Jeremy C. Ely, Andrew J. Sole, James M. Lea, Stephen J. Livingstone, Julie M. Jones, and J. Melchior van Wessem
The Cryosphere, 15, 5785–5804, https://doi.org/10.5194/tc-15-5785-2021, https://doi.org/10.5194/tc-15-5785-2021, 2021
Short summary
Short summary
Lakes form on the surface of the Antarctic Ice Sheet during the summer. These lakes can generate further melt, break up floating ice shelves and alter ice dynamics. Here, we describe a new automated method for mapping surface lakes and apply our technique to the Amery Ice Shelf between 2005 and 2020. Lake area is highly variable between years, driven by large-scale climate patterns. This technique will help us understand the role of Antarctic surface lakes in our warming world.
Douglas P. Steen, Joseph S. Stoner, Jason P. Briner, and Darrell S. Kaufman
Geochronology Discuss., https://doi.org/10.5194/gchron-2021-19, https://doi.org/10.5194/gchron-2021-19, 2021
Publication in GChron not foreseen
Short summary
Short summary
Paleomagnetic data from Cascade Lake (Brooks Range, Alaska) extend the radiometric-based age model of the sedimentary sequence extending back 21 kyr. Correlated ages based on prominent features in paleomagnetic secular variations (PSV) diverge from the radiometric ages in the upper 1.6 m, by up to about 2000 years at around 4 ka. Four late Holocene cryptotephra in this section support the PSV chronology and suggest the influence of hard water or aged organic material.
Cody C. Routson, Darrell S. Kaufman, Nicholas P. McKay, Michael P. Erb, Stéphanie H. Arcusa, Kendrick J. Brown, Matthew E. Kirby, Jeremiah P. Marsicek, R. Scott Anderson, Gonzalo Jiménez-Moreno, Jessica R. Rodysill, Matthew S. Lachniet, Sherilyn C. Fritz, Joseph R. Bennett, Michelle F. Goman, Sarah E. Metcalfe, Jennifer M. Galloway, Gerrit Schoups, David B. Wahl, Jesse L. Morris, Francisca Staines-Urías, Andria Dawson, Bryan N. Shuman, Daniel G. Gavin, Jeffrey S. Munroe, and Brian F. Cumming
Earth Syst. Sci. Data, 13, 1613–1632, https://doi.org/10.5194/essd-13-1613-2021, https://doi.org/10.5194/essd-13-1613-2021, 2021
Short summary
Short summary
We present a curated database of western North American Holocene paleoclimate records, which have been screened on length, resolution, and geochronology. The database gathers paleoclimate time series that reflect temperature, hydroclimate, or circulation features from terrestrial and marine sites, spanning a region from Mexico to Alaska. This publicly accessible collection will facilitate a broad range of paleoclimate inquiry.
Chris M. Brierley, Anni Zhao, Sandy P. Harrison, Pascale Braconnot, Charles J. R. Williams, David J. R. Thornalley, Xiaoxu Shi, Jean-Yves Peterschmitt, Rumi Ohgaito, Darrell S. Kaufman, Masa Kageyama, Julia C. Hargreaves, Michael P. Erb, Julien Emile-Geay, Roberta D'Agostino, Deepak Chandan, Matthieu Carré, Partrick J. Bartlein, Weipeng Zheng, Zhongshi Zhang, Qiong Zhang, Hu Yang, Evgeny M. Volodin, Robert A. Tomas, Cody Routson, W. Richard Peltier, Bette Otto-Bliesner, Polina A. Morozova, Nicholas P. McKay, Gerrit Lohmann, Allegra N. Legrande, Chuncheng Guo, Jian Cao, Esther Brady, James D. Annan, and Ayako Abe-Ouchi
Clim. Past, 16, 1847–1872, https://doi.org/10.5194/cp-16-1847-2020, https://doi.org/10.5194/cp-16-1847-2020, 2020
Short summary
Short summary
This paper provides an initial exploration and comparison to climate reconstructions of the new climate model simulations of the mid-Holocene (6000 years ago). These use state-of-the-art models developed for CMIP6 and apply the same experimental set-up. The models capture several key aspects of the climate, but some persistent issues remain.
Bronwen L. Konecky, Nicholas P. McKay, Olga V. Churakova (Sidorova), Laia Comas-Bru, Emilie P. Dassié, Kristine L. DeLong, Georgina M. Falster, Matt J. Fischer, Matthew D. Jones, Lukas Jonkers, Darrell S. Kaufman, Guillaume Leduc, Shreyas R. Managave, Belen Martrat, Thomas Opel, Anais J. Orsi, Judson W. Partin, Hussein R. Sayani, Elizabeth K. Thomas, Diane M. Thompson, Jonathan J. Tyler, Nerilie J. Abram, Alyssa R. Atwood, Olivier Cartapanis, Jessica L. Conroy, Mark A. Curran, Sylvia G. Dee, Michael Deininger, Dmitry V. Divine, Zoltán Kern, Trevor J. Porter, Samantha L. Stevenson, Lucien von Gunten, and Iso2k Project Members
Earth Syst. Sci. Data, 12, 2261–2288, https://doi.org/10.5194/essd-12-2261-2020, https://doi.org/10.5194/essd-12-2261-2020, 2020
Paul D. Zander, Sönke Szidat, Darrell S. Kaufman, Maurycy Żarczyński, Anna I. Poraj-Górska, Petra Boltshauser-Kaltenrieder, and Martin Grosjean
Geochronology, 2, 63–79, https://doi.org/10.5194/gchron-2-63-2020, https://doi.org/10.5194/gchron-2-63-2020, 2020
Short summary
Short summary
Recent technological advances allow researchers to obtain radiocarbon ages from smaller samples than previously possible. We investigate the reliability and precision of radiocarbon ages obtained from miniature (11–150 μg C) samples of terrestrial plant fragments taken from sediment cores from Lake Żabińskie, Poland. We further investigate how sampling density (the number of ages per 1000 years) and sample mass (which is related to age precision) influence the performance of age–depth models.
Ellie Broadman, Lorna L. Thurston, Erik Schiefer, Nicholas P. McKay, David Fortin, Jason Geck, Michael G. Loso, Matt Nolan, Stéphanie H. Arcusa, Christopher W. Benson, Rebecca A. Ellerbroek, Michael P. Erb, Cody C. Routson, Charlotte Wiman, A. Jade Wong, and Darrell S. Kaufman
Earth Syst. Sci. Data, 11, 1957–1970, https://doi.org/10.5194/essd-11-1957-2019, https://doi.org/10.5194/essd-11-1957-2019, 2019
Short summary
Short summary
Rapid climate warming is impacting physical processes in Arctic environments. Glacier–fed lakes are influenced by many of these processes, and they are impacted by the changing behavior of weather, glaciers, and rivers. We present data from weather stations, river gauging stations, lake moorings, and more, following 4 years of environmental monitoring in the watershed of Lake Peters, a glacier–fed lake in Arctic Alaska. These data can help us study the changing dynamics of this remote setting.
Gabriel West, Darrell S. Kaufman, Francesco Muschitiello, Matthias Forwick, Jens Matthiessen, Jutta Wollenburg, and Matt O'Regan
Geochronology, 1, 53–67, https://doi.org/10.5194/gchron-1-53-2019, https://doi.org/10.5194/gchron-1-53-2019, 2019
Short summary
Short summary
We report amino acid racemization analyses of foraminifera from well-dated sediment cores from the Yermak Plateau, Arctic Ocean. Sample ages are compared with model predictions, revealing that the rates of racemization generally conform to a global compilation of racemization rates at deep-sea sites. These results highlight the need for further studies to test and explain the origin of the purportedly high rate of racemization indicated by previous analyses of central Arctic sediments.
Robert Tardif, Gregory J. Hakim, Walter A. Perkins, Kaleb A. Horlick, Michael P. Erb, Julien Emile-Geay, David M. Anderson, Eric J. Steig, and David Noone
Clim. Past, 15, 1251–1273, https://doi.org/10.5194/cp-15-1251-2019, https://doi.org/10.5194/cp-15-1251-2019, 2019
Short summary
Short summary
An updated Last Millennium Reanalysis is presented, using an expanded multi-proxy database, and proxy models representing the seasonal characteristics of proxy records, in addition to the dual sensitivity to temperature and moisture of tree-ring-width chronologies. We show enhanced skill in spatial reconstructions of key climate variables in the updated reanalysis, compared to an earlier version, resulting from the combined influences of the enhanced proxy network and improved proxy modeling.
Chris S. M. Turney, Helen V. McGregor, Pierre Francus, Nerilie Abram, Michael N. Evans, Hugues Goosse, Lucien von Gunten, Darrell Kaufman, Hans Linderholm, Marie-France Loutre, and Raphael Neukom
Clim. Past, 15, 611–615, https://doi.org/10.5194/cp-15-611-2019, https://doi.org/10.5194/cp-15-611-2019, 2019
Short summary
Short summary
This PAGES (Past Global Changes) 2k (climate of the past 2000 years working group) special issue of Climate of the Past brings together the latest understanding of regional change and impacts from PAGES 2k groups across a range of proxies and regions. The special issue has emerged from a need to determine the magnitude and rate of change of regional and global climate beyond the timescales accessible within the observational record.
Richard H. Levy, Gavin B. Dunbar, Marcus J. Vandergoes, Jamie D. Howarth, Tony Kingan, Alex R. Pyne, Grant Brotherston, Michael Clarke, Bob Dagg, Matthew Hill, Evan Kenton, Steve Little, Darcy Mandeno, Chris Moy, Philip Muldoon, Patrick Doyle, Conrad Raines, Peter Rutland, Delia Strong, Marianna Terezow, Leise Cochrane, Remo Cossu, Sean Fitzsimons, Fabio Florindo, Alexander L. Forrest, Andrew R. Gorman, Darrell S. Kaufman, Min Kyung Lee, Xun Li, Pontus Lurcock, Nicholas McKay, Faye Nelson, Jennifer Purdie, Heidi A. Roop, S. Geoffrey Schladow, Abha Sood, Phaedra Upton, Sharon L. Walker, and Gary S. Wilson
Sci. Dril., 24, 41–50, https://doi.org/10.5194/sd-24-41-2018, https://doi.org/10.5194/sd-24-41-2018, 2018
Short summary
Short summary
A new annually resolvable sedimentary record of southern hemisphere climate has been recovered from Lake Ohau, South Island, New Zealand. The Lake Ohau Climate History (LOCH) Project acquired cores from two sites that preserve an 80 m thick sequence of laminated mud that accumulated since the lake formed ~ 17 000 years ago. Cores were recovered using a purpose-built barge and drilling system designed to recover soft sediment from relatively thick sedimentary sequences at water depths up to 100 m.
James M. Lea
Earth Surf. Dynam., 6, 551–561, https://doi.org/10.5194/esurf-6-551-2018, https://doi.org/10.5194/esurf-6-551-2018, 2018
Short summary
Short summary
The new, free and easy-to-use tools in this paper (GEEDiT, GEEDiT-Reviewer and MaQiT) allow users to visualise, map and review margins from full satellite records of Landsat 4–8 and Sentinel 1–2 in addition to quantifying these margin changes with unprecedented speed. This allows previously prohibitive volumes of remote-sensing data to be analysed easily, flexibly and rapidly. These tools have potential applications across the geosciences for the exploration and analysis of satellite imagery.
Bryan N. Shuman, Cody Routson, Nicholas McKay, Sherilyn Fritz, Darrell Kaufman, Matthew E. Kirby, Connor Nolan, Gregory T. Pederson, and Jeannine-Marie St-Jacques
Clim. Past, 14, 665–686, https://doi.org/10.5194/cp-14-665-2018, https://doi.org/10.5194/cp-14-665-2018, 2018
Short summary
Short summary
A synthesis of 93 published records reveals that moisture availability increased over large portions of North America over the past 2000 years, the Common Era (CE). In many records, the second millennium CE tended to be wetter than the first millennium CE. The long-term changes formed the background for annual to multi-decade variations, such as "mega-droughts", and also provide a context for amplified rates of hydrologic change today.
Darrell S. Kaufman and PAGES 2k special-issue editorial team
Clim. Past, 14, 593–600, https://doi.org/10.5194/cp-14-593-2018, https://doi.org/10.5194/cp-14-593-2018, 2018
Short summary
Short summary
We explain the procedure used to attain a high and consistent level of data stewardship across a special issue of the journal Climate of the Past. We discuss the challenges related to (1) determining which data are essential for public archival, (2) using data generated by others, and (3) understanding data citations. We anticipate that open-data sharing in paleo sciences will accelerate as the advantages become more evident and as practices that reduce data loss become the accepted convention.
H. S. Sundqvist, D. S. Kaufman, N. P. McKay, N. L. Balascio, J. P. Briner, L. C. Cwynar, H. P. Sejrup, H. Seppä, D. A. Subetto, J. T. Andrews, Y. Axford, J. Bakke, H. J. B. Birks, S. J. Brooks, A. de Vernal, A. E. Jennings, F. C. Ljungqvist, K. M. Rühland, C. Saenger, J. P. Smol, and A. E. Viau
Clim. Past, 10, 1605–1631, https://doi.org/10.5194/cp-10-1605-2014, https://doi.org/10.5194/cp-10-1605-2014, 2014
Related subject area
Discipline: Glaciers | Subject: Climate Interactions
Unravelling the sources of uncertainty in glacier runoff projections in the Patagonian Andes (40–56° S)
Triggers of the 2022 Larsen B multi-year landfast sea ice breakout and initial glacier response
Climatic control of the surface mass balance of the Patagonian Icefields
On the attribution of industrial-era glacier mass loss to anthropogenic climate change
Distributed summer air temperatures across mountain glaciers in the south-east Tibetan Plateau: temperature sensitivity and comparison with existing glacier datasets
Glacier runoff variations since 1955 in the Maipo River basin, in the semiarid Andes of central Chile
Impact of warming shelf waters on ice mélange and terminus retreat at a large SE Greenland glacier
A long-term dataset of climatic mass balance, snow conditions, and runoff in Svalbard (1957–2018)
Rodrigo Aguayo, Fabien Maussion, Lilian Schuster, Marius Schaefer, Alexis Caro, Patrick Schmitt, Jonathan Mackay, Lizz Ultee, Jorge Leon-Muñoz, and Mauricio Aguayo
The Cryosphere, 18, 5383–5406, https://doi.org/10.5194/tc-18-5383-2024, https://doi.org/10.5194/tc-18-5383-2024, 2024
Short summary
Short summary
Predicting how much water will come from glaciers in the future is a complex task, and there are many factors that make it uncertain. Using a glacier model, we explored 1920 scenarios for each glacier in the Patagonian Andes. We found that the choice of the historical climate data was the most important factor, while other factors such as different data sources, climate models and emission scenarios played a smaller role.
Naomi E. Ochwat, Ted A. Scambos, Alison F. Banwell, Robert S. Anderson, Michelle L. Maclennan, Ghislain Picard, Julia A. Shates, Sebastian Marinsek, Liliana Margonari, Martin Truffer, and Erin C. Pettit
The Cryosphere, 18, 1709–1731, https://doi.org/10.5194/tc-18-1709-2024, https://doi.org/10.5194/tc-18-1709-2024, 2024
Short summary
Short summary
On the Antarctic Peninsula, there is a small bay that had sea ice fastened to the shoreline (
fast ice) for over a decade. The fast ice stabilized the glaciers that fed into the ocean. In January 2022, the fast ice broke away. Using satellite data we found that this was because of low sea ice concentrations and a high long-period ocean wave swell. We find that the glaciers have responded to this event by thinning, speeding up, and retreating by breaking off lots of icebergs at remarkable rates.
Tomás Carrasco-Escaff, Maisa Rojas, René Darío Garreaud, Deniz Bozkurt, and Marius Schaefer
The Cryosphere, 17, 1127–1149, https://doi.org/10.5194/tc-17-1127-2023, https://doi.org/10.5194/tc-17-1127-2023, 2023
Short summary
Short summary
In this study, we investigate the interplay between climate and the Patagonian Icefields. By modeling the glacioclimatic conditions of the southern Andes, we found that the annual variations in net surface mass change experienced by these icefields are mainly controlled by annual variations in the air pressure field observed near the Drake Passage. Little dependence on main modes of variability was found, suggesting the Drake Passage as a key region for understanding the Patagonian Icefields.
Gerard H. Roe, John Erich Christian, and Ben Marzeion
The Cryosphere, 15, 1889–1905, https://doi.org/10.5194/tc-15-1889-2021, https://doi.org/10.5194/tc-15-1889-2021, 2021
Short summary
Short summary
The worldwide retreat of mountain glaciers and consequent loss of ice mass is one of the most obvious signs of a changing climate and has significant implications for the hydrology and natural hazards in mountain landscapes. Consistent with our understanding of the human role in temperature change, we demonstrate that the central estimate of the size of the human-caused mass loss is essentially 100 % of the observed loss. This assessment resolves some important inconsistencies in the literature.
Thomas E. Shaw, Wei Yang, Álvaro Ayala, Claudio Bravo, Chuanxi Zhao, and Francesca Pellicciotti
The Cryosphere, 15, 595–614, https://doi.org/10.5194/tc-15-595-2021, https://doi.org/10.5194/tc-15-595-2021, 2021
Short summary
Short summary
Near surface air temperature (Ta) is important for simulating the melting of glaciers, though its variability in space and time on mountain glaciers is still poorly understood. We combine new Ta observations on glacier in Tibet with several glacier datasets around the world to explore the applicability of an existing method to estimate glacier Ta based upon glacier flow distance. We make a first step at generalising a method and highlight the remaining unknowns for this field of research.
Álvaro Ayala, David Farías-Barahona, Matthias Huss, Francesca Pellicciotti, James McPhee, and Daniel Farinotti
The Cryosphere, 14, 2005–2027, https://doi.org/10.5194/tc-14-2005-2020, https://doi.org/10.5194/tc-14-2005-2020, 2020
Short summary
Short summary
We reconstruct past glacier changes (1955–2016) and estimate the committed ice loss in the Maipo River basin (semi-arid Andes of Chile), with a focus on glacier runoff. We found that glacier volume has decreased by one-fifth since 1955 and that glacier runoff shows a sequence of decreasing maxima starting in a severe drought in 1968. As meltwater originating from the Andes plays a key role in this dry region, our results can be useful for developing adaptation or mitigation strategies.
Suzanne L. Bevan, Adrian J. Luckman, Douglas I. Benn, Tom Cowton, and Joe Todd
The Cryosphere, 13, 2303–2315, https://doi.org/10.5194/tc-13-2303-2019, https://doi.org/10.5194/tc-13-2303-2019, 2019
Short summary
Short summary
Kangerlussuaq Glacier in Greenland retreated significantly in the early 2000s and typified the response of calving glaciers to climate change. Satellite images show that it has recently retreated even further. The current retreat follows the appearance of extremely warm surface waters on the continental shelf during the summer of 2016, which likely entered the fjord and caused the rigid mass of sea ice and icebergs, which normally inhibits calving, to melt and break up.
Ward van Pelt, Veijo Pohjola, Rickard Pettersson, Sergey Marchenko, Jack Kohler, Bartłomiej Luks, Jon Ove Hagen, Thomas V. Schuler, Thorben Dunse, Brice Noël, and Carleen Reijmer
The Cryosphere, 13, 2259–2280, https://doi.org/10.5194/tc-13-2259-2019, https://doi.org/10.5194/tc-13-2259-2019, 2019
Short summary
Short summary
The climate in Svalbard is undergoing amplified change compared to the global mean, which has a strong impact on the climatic mass balance of glaciers and the state of seasonal snow in land areas. In this study we analyze a coupled energy balance–subsurface model dataset, which provides detailed information on distributed climatic mass balance, snow conditions, and runoff across Svalbard between 1957 and 2018.
Cited articles
Anderson, B., Mackintosh, A., Stumm, D., George, L., Kerr, T., Winter–Billington, A., and Fitzsimons, S.: Climate sensitivity of a high–precipitation glacier in New Zealand, J. Glaciol., 56, 114–128, 2010.
Bauder, A., Funk, M., and Huss, M.: Ice-volume changes of selected glaciers in the Swiss Alps since the end of the 19th century, Ann. Glaciol., 46, 145–149, 2007.
Bindschadler, R., Dowdeswell, J., Hall, D., and Winther, J. G.: Glaciological applications with Landsat–7 imagery: early assessments, Remote Sens. Environ., 78, 163–179, 2001.
Bintanja, R. and Andry, O.: Towards a rain–dominated Arctic, Nat. Clim. Change, 7, 263–267, 2017.
Bjørk, A. A., Kjær, K. H., Korsgaard, N. J., Khan, S. A., Kjeldsen, K. K., Andresen, C. S., Box, J. E., Larsen, N. K., and Funder, S.: An aerial view of 80 years of climate–related glacier fluctuations in southeast Greenland, Nat. Geosci., 5, 427–432, 2012.
Bjørk, A. A., Aagaard, S., Lütt, A., Khan, S. A., Box, J. E., Kjeldsen, K. K., Larsen, N. K., Korsgaard, N. J., Cappelen, J., Colgan, W. T., and Machguth, H.: Changes in Greenland's peripheral glaciers linked to the North Atlantic Oscillation, Nat. Clim. Change, 8, 48–52, 2018.
Bolibar, J., Rabatel, A., Gouttevin, I., Galiez, C., Condom, T., and Sauquet, E.: Deep learning applied to glacier evolution modelling, The Cryosphere, 14, 565–584, https://doi.org/10.5194/tc-14-565-2020, 2020.
Bolibar, J., Rabatel, A., Gouttevin, I., Zekollari, H., and Galiez, C.: Nonlinear sensitivity of glacier mass balance to future climate change unveiled by deep learning, Nat. Commun., 13, 409, https://doi.org/10.1038/s41467-022-28033-0, 2022.
Braithwaite, R. J.: Can the mass balance of a glacier be estimated from its equilibrium–line altitude?, J. Glaciol., 30, 364–368, 1984.
Braithwaite, R. J. and Müller, F.: On the parameterization of glacier equilibrium line altitude, IAHS Publ, 126, 263–271, 1980.
Braithwaite, R. J. and Zhang, Y.: Sensitivity of mass balance of five Swiss glaciers to temperature changes assessed by tuning a degree–day model, J. Glaciol., 46, 7–14, 2000.
Braithwaite, R. J., Zhang, Y., and Raper, S. C. B.: Temperature sensitivity of the mass balance of mountain glaciers and ice caps as a climatological characteristic, Zeitschrift fur Gletscherkunde und Glazialgeologie, 38, 35–61, 2002.
Brooks, J. P., Larocca, L. J., and Axford, Y. L.: Little Ice Age climate in southernmost Greenland inferred from quantitative geospatial analyses of alpine glacier reconstructions, Quaternary Sci. Rev., 293, 107701, https://doi.org/10.1016/j.quascirev.2022.107701, 2022.
Caidong, C. and Sorteberg, A.: Modelled mass balance of Xibu glacier, Tibetan Plateau: sensitivity to climate change, J. Glaciol., 56, 235–248, 2010.
Carrivick, J. L., Andreassen, L. M., Nesje, A., and Yde, J. C.: A reconstruction of Jostedalsbreen during the Little Ice Age and geometric changes to outlet glaciers since then, Quaternary Sci. Rev., 284, 107501, https://doi.org/10.1016/j.quascirev.2022.107501, 2022.
Carrivick, J. L., Boston, C. M., Sutherland, J. L., Pearce, D., Armstrong, H., Bjørk, A., Kjeldsen, K. K., Abermann, J., Oien, R. P., Grimes, M., and James, W.H.: Mass loss of glaciers and ice caps across Greenland since the Little Ice Age, Geophys. Res. Lett., 50, e2023GL103950, https://doi.org/10.1029/2023GL103950, 2023.
Cogley, J. G., Arendt, A. A., Bauder, A., Braithwaite, R. J., Hock, R., Jansson, P., Kaser, G., Moller, M., Nicholson, L., Rasmussen, L. A., and Zemp, M.: Glossary of glacier mass balance terms and related terms (IHP–VII Technical Documents in Hydrology No. 86, IACS Contribution No. 2), UNESCO–International Hydrological Programme, Paris, 2011.
Curley, A. N., Kochtitzky, W. H., Edwards, B. R., and Copland, L.: Glacier changes over the past 144 years at Alexandra Fiord, Ellesmere Island, Canada, J. Glaciol., 67, 511–522, 2021.
Davaze, L., Rabatel, A., Dufour, A., Hugonnet, R., and Arnaud, Y.: Region–wide annual glacier surface mass balance for the European Alps from 2000 to 2016, Front. Earth Sci., 8, 149, https://doi.org/10.3389/feart.2020.00149, 2020.
DeBeer, C. M. and Sharp, M. J.: Topographic influences on recent changes of very small glaciers in the Monashee Mountains, British Columbia, Canada, J. Glaciol., 55, 691–700, 2009.
Denton, G. H., Alley, R. B., Comer, G. C., and Broecker, W. S.: The role of seasonality in abrupt climate change, Quaternary Sci. Rev., 24, 1159–1182, 2005.
Dowdeswell, J. A., Hagen, J. O., Björnsson, H., Glazovsky, A. F., Harrison, W. D., Holmlund, P., Jania, J., Koerner, R. M., Lefauconnier, B., Ommanney, C. S. L., and Thomas, R. H.: The mass balance of circum-Arctic glaciers and recent climate change, Quaternary Res., 48, 1–14, 1997.
Gerbaux, M., Genthon, C., Etchevers, P., Vincent, C., and Dedieu, J. P.: Surface mass balance of glaciers in the French Alps: distributed modeling and sensitivity to climate change, J. Glaciol., 51, 561–572, 2005.
Gesch, D., Oimoen, M., Danielson, J., and Meyer, D.: Validation of the ASTER global digital elevation model version 3 over the conterminous United States, The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 41, 143–148, 2016.
Geyman, E. C., van Pelt, J. J. W., Maloof, A. C., Aas, H. F., and Kohler, J.: Historical glacier change on Svalbard predicts doubling of mass loss by 2100, Nature, 601, 374–379, 2022.
Gomis-Cebolla, J., Rattayova, V., Salazar–Galán, S., and Francés, F.: Evaluation of ERA5 and ERA5–Land reanalysis precipitation datasets over Spain (1951–2020), Atmospheric Res., 284, 106606, https://doi.org/10.1016/j.atmosres.2023.106606, 2023.
Guo, Z., Geng, L., Shen, B., Wu, Y., Chen, A., and Wang, N.: Spatiotemporal variability in the glacier snowline altitude across high mountain asia and potential driving factors, Remote Sens., 13, 425, https://doi.org/10.3390/rs13030425, 2021.
Hamm, A., Arndt, A., Kolbe, C., Wang, X., Thies, B., Boyko, O., Reggiani, P., Scherer, D., Bendix, J., and Schneider, C.: Intercomparison of gridded precipitation datasets over a sub–region of the Central Himalaya and the Southwestern Tibetan Plateau, Water, 12, 3271, https://doi.org/10.3390/w12113271, 2020.
Hock, R., Rasul, G., Adler, C., Cáceres, B., Gruber, S., Hirabayashi, Y., Jackson, M., Kääb, A., Kang, S., Kutuzov, S., Milner, Al., Molau, U., Morin, S., Orlove, B., and Steltzer, H.: High Mountain Areas, in: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, edited by: Pörtner, H.-O., Roberts, D. C., Masson-Delmotte, V., Zhai, P., Tignor, M., Poloczanska, E., Mintenbeck, K., Alegría, A., Nicolai, M., Okem, A., Petzold, J., Rama, B., and Weyer, N. M., Cambridge University Press, Cambridge, UK and New York, NY, USA, 131–202, https://doi.org/10.1017/9781009157964.004, 2019.
Hugonnet, R., McNabb, R., Berthier, E., Menounos, B., Nuth, C., Girod, L., Farinotti, D., Huss, M., Dussaillant, I., Brun, F., and Kääb, A.: Accelerated global glacier mass loss in the early twenty–first century, Nature, 592, 726–731, 2021.
Huss, M. and Fischer, M.: Sensitivity of very small glaciers in the Swiss Alps to future climate change, Front. Earth Sci., 4, 34, https://doi.org/10.3389/feart.2016.00034, 2016.
Joerin, U. E., Nicolussi, K., Fischer, A., Stocker, T. F., and Schlüchter, C.: Holocene optimum events inferred from subglacial sediments at Tschierva Glacier, Eastern Swiss Alps, Quaternary Sci. Rev., 27, 337–350, 2008.
Khan, S. A., Bjørk, A. A., Bamber, J. L., Morlighem, M., Bevis, M., Kjær, K. H., Mouginot, J., Løkkegaard, A., Holland, D. M., Aschwanden, A., and Zhang, B.: Centennial response of Greenland's three largest outlet glaciers, Nat. Commun., 11, 5718, https://doi.org/10.1038/s41467-020-19580-5, 2020.
Larocca, L.: Snowline altitudes and shapefiles for 269 glaciers, Pan-Arctic, 1984–2022, Arctic Data Center [data set], https://doi.org/10.18739/A2ZS2KF5T, 2024.
Larocca, L. J. and Axford, Y.: Arctic glaciers and ice caps through the Holocene:a circumpolar synthesis of lake-based reconstructions, Clim. Past, 18, 579–606, https://doi.org/10.5194/cp-18-579-2022, 2022.
Larocca, L. J., Axford, Y., Bjørk, A. A., Lasher, G. E., and Brooks, J. P.: Local glaciers record delayed peak Holocene warmth in south Greenland, Quaternary Sci. Rev., 241, 106421, https://doi.org/10.1016/j.quascirev.2020.106421, 2020a.
Larocca, L. J., Axford, Y., Woodroffe, S. A., Lasher, G. E., and Gawin, B.: Holocene glacier and ice cap fluctuations in southwest Greenland inferred from two lake records, Quaternary Sci. Rev., 246, 106529, https://doi.org/10.1016/j.quascirev.2020.106529, 2020b.
Larocca, L. J., Twining-Ward, M., Axford, Y., Schweinsberg, A. D., Larsen, S. H., Westergaard-Nielsen, A., Luetzenburg, G., Briner, J. P., Kjeldsen, K. K., and Bjørk, A. A.: Greenland–wide accelerated retreat of peripheral glaciers in the twenty-first century, Nat. Clim. Change, 13, 1324–1328, 2023.
Lea, J. M.: The Google Earth Engine Digitisation Tool (GEEDiT) and the Margin change Quantification Tool (MaQiT) – simple tools for the rapid mapping and quantification of changing Earth surface margins, Earth Surf. Dynam., 6, 551–561, https://doi.org/10.5194/esurf-6-551-2018, 2018.
Li, X., Wang, N., and Wu, Y.: Automated Glacier Snow Line Altitude Calculation Method Using Landsat Series Images in the Google Earth Engine Platform, Remote Sens., 14, 2377, https://doi.org/10.3390/rs14102377, 2022.
Lorrey, A. M., Vargo, L., Purdie, H., Anderson, B., Cullen, N. J., Sirguey, P., Mackintosh, A., Willsman, A., Macara, G., and Chinn, W.: Southern Alps equilibrium line altitudes: four decades of observations show coherent glacier–climate responses and a rising snowline trend, J. Glaciol., 68, 1127–1140, 2022.
Marzeion, B., Hock, R., Anderson, B., Bliss, A., Champollion, N., Fujita, K., Huss, M., Immerzeel, W. W., Kraaijenbrink, P., Malles, J. H., and Maussion, F.: Partitioning the uncertainty of ensemble projections of global glacier mass change, Earth's Future, 8, e2019EF001470, https://doi.org/10.1029/2019EF001470, 2020.
McGrath, D., Sass, L., O'Neel, S., Arendt, A., and Kienholz, C.: Hypsometric control on glacier mass balance sensitivity in Alaska and northwest Canada, Earth's Future, 5, 324–336, 2017.
Meier, M. F.: Proposed definitions for glacier mass budget terms, J. Glaciol., 4, 252–263, 1962.
Mernild, S. H., Knudsen, N. T., Lipscomb, W. H., Yde, J. C., Malmros, J. K., Hasholt, B., and Jakobsen, B. H.: Increasing mass loss from Greenland's Mittivakkat Gletscher, The Cryosphere, 5, 341–348, https://doi.org/10.5194/tc-5-341-2011, 2011.
Mernild, S. H., Pelto, M., Malmros, J. K., Yde, J. C., Knudsen, N. T., and Hanna, E.: Identification of snow ablation rate, ELA, AAR and net mass balance using transient snowline variations on two Arctic glaciers, J. Glaciol., 59, 649–659, 2013.
Muñoz-Sabater, J.: ERA5-Land hourly data from 1950 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.e2161bac, 2019a.
Muñoz-Sabater, J.: ERA5–Land monthly averaged data from 1950 to present, Copernicus Climate Change Service (C3S) Climate Data Store (CDS) [data set], https://doi.org/10.24381/cds.68d2bb30, 2019b.
NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team: ASTER Global Digital Elevation Model V003, NASA EOSDIS Land Processes Distributed Active Archive Center [data set], https://doi.org/10.5067/ASTER/ASTGTM.003, 2019.
Oerlemans, J.: Climate sensitivity of glaciers in southern Norway: application of an energy–balance model to Nigardsbreen, Hellstugubreen and Alfotbreen, J. Glaciol., 38, 223–232, 1992.
Oerlemans, J.: Glaciers and climate change, A. A. Balkema Publishers, Rotterdam, 2001.
Oerlemans, J.: Extracting a climate signal from 169 glacier records, Science, 308, 675–677, 2005.
Oerlemans, J. and Hoogendoorn, N. C.: Mass–balance gradients and climatic change, J. Glaciol., 35, 399–405, 1989.
Ohmura, A. and Boettcher, M.: On the Shift of Glacier Equilibrium Line Altitude (ELA) under the Changing Climate, Water, 14, 2821, https://doi.org/10.3390/w14182821, 2022.
Ohmura, A., Kasser, P., and Funk, M.: Climate at the equilibrium line of glaciers, J. Glaciol., 38, 397–411, 1992.
Olson, M. and Rupper, S.: Impacts of topographic shading on direct solar radiation for valley glaciers in complex topography, The Cryosphere, 13, 29–40, https://doi.org/10.5194/tc-13-29-2019, 2019.
Papasodoro, C., Berthier, E., Royer, A., Zdanowicz, C., and Langlois, A.: Area, elevation and mass changes of the two southernmost ice caps of the Canadian Arctic Archipelago between 1952 and 2014, The Cryosphere, 9, 1535–1550, https://doi.org/10.5194/tc-9-1535-2015, 2015.
Pelto, M.: Utility of late summer transient snowline migration rate on Taku Glacier, Alaska, The Cryosphere, 5, 1127–1133, https://doi.org/10.5194/tc-5-1127-2011, 2011.
Pfeffer, W. T., Arendt, A. A., Bliss, A., Bolch, T., Cogley, J. G., Gardner, A. S., Hagen, J. O., Hock, R., Kaser, G., Kienholz, C., and Miles, E. S.: The Randolph Glacier Inventory: a globally complete inventory of glaciers, J. Glaciol., 60, 537–552, 2014.
Prantl, H., Nicholson, L., Sailer, R., Hanzer, F., Juen, I. F., and Rastner, P.: Glacier snowline determination from terrestrial laser scanning intensity data, Geosciences, 7, 60, https://doi.org/10.3390/geosciences7030060, 2017.
Rabatel, A., Dedieu, J. P., and Vincent, C.: Using remote-sensing data to determine equilibrium–line altitude and mass–balance time series: validation on three French glaciers, 1994–2002, J. Glaciol., 51, 539–546, 2005.
Rabatel, A., Bermejo, A., Loarte, E., Soruco, A., Gomez, J., Leonardini, G., Vincent, C., and Sicart, J. E.: Can the snowline be used as an indicator of the equilibrium line and mass balance for glaciers in the outer tropics?, J. Glaciol., 58, 1027–1036, 2012.
Rabatel, A., Letréguilly, A., Dedieu, J.-P., and Eckert, N.: Changes in glacier equilibrium-line altitude in the western Alps from 1984 to 2010: evaluation by remote sensing and modeling of the morpho-topographic and climate controls, The Cryosphere, 7, 1455–1471, https://doi.org/10.5194/tc-7-1455-2013, 2013.
Racoviteanu, A. E., Rittger, K., and Armstrong, R.: An automated approach for estimating snowline altitudes in the Karakoram and eastern Himalaya from remote sensing, Front. Earth Sci., 7, 220, https://doi.org/10.3389/feart.2019.00220, 2019.
Rantanen, M., Karpechko, A. Y., Lipponen, A., Nordling, K., Hyvärinen, O., Ruosteenoja, K., Vihma, T., and Laaksonen, A.: The Arctic has warmed nearly four times faster than the globe since 1979, Commun. Earth Environ., 3, 168, https://doi.org/10.1038/s43247-022-00498-3, 2022.
Rastner, P., Prinz, R., Notarnicola, C., Nicholson, L., Sailer, R., Schwaizer, G., and Paul, F.: On the automated mapping of snow cover on glaciers and calculation of snow line altitudes from multi–temporal landsat data, Remote Sens., 11, 1410, https://doi.org/10.3390/rs11121410, 2019.
Réveillet, M., Six, D., Vincent, C., Rabatel, A., Dumont, M., Lafaysse, M., Morin, S., Vionnet, V., and Litt, M.: Relative performance of empirical and physical models in assessing the seasonal and annual glacier surface mass balance of Saint-Sorlin Glacier (French Alps), The Cryosphere, 12, 1367–1386, https://doi.org/10.5194/tc-12-1367-2018, 2018.
RGI Consortium: Randolph Glacier Inventory – A Dataset of Global Glacier Outlines, Version 6, Boulder, Colorado USA, National Snow and Ice Data Center [data set], https://doi.org/10.7265/4m1f-gd79, 2017.
Rounce, D. R., Hock, R., Maussion, F., Hugonnet, R., Kochtitzky, W., Huss, M., Berthier, E., Brinkerhoff, D., Compagno, L., Copland, L., and Farinotti, D.: Global glacier change in the 21st century: Every increase in temperature matters, Science, 379, 78–83, 2023.
Rupper, S. and Roe, G.: Glacier changes and regional climate: a mass and energy balance approach, J. Climate, 21, 5384–5401, 2008.
Sagredo, E. A., Rupper, S., and Lowell, T. V.: Sensitivities of the equilibrium line altitude to temperature and precipitation changes along the Andes, Quaternary Res., 81, 355–366, 2014.
Sikorski, J. J., Kaufman, D. S., Manley, W. F., and Nolan, M.: Glacial–geologic evidence for decreased precipitation during the Little Ice Age in the Brooks Range, Alaska, Arct. Antarct. Alp. Res., 41, 138–150, 2009.
Six, D. and Vincent, C.: Sensitivity of mass balance and equilibrium–line altitude to climate change in the French Alps, J. Glaciol., 60, 867–878, 2014.
Vincent, C.: Influence of climate change over the 20th century on four French glacier mass balances, J. Geophys. Res.-Atmos., 107, ACL-4, https://doi.org/10.1029/2001JD000832, 2002.
Wallinga, J. and Van De Wal, R. S.: Sensitivity of Rhonegletscher, Switzerland, to climate change: experiments with a one-dimensional flowline model, J. Glaciol., 44, 383–393, 1998.
Way, R. G., Bell, T., and Barrand, N. E.: An inventory and topographic analysis of glaciers in the Torngat Mountains, northern Labrador, Canada, J. Glaciol., 60, 945–956, 2014.
WGMS: Global Glacier Change Bulletin No. 4 (2018–2019), edited by: Zemp, M., Nussbaumer, S. U., GärtnerRoer, I., Bannwart, J., Paul, F., and Hoelzle, M., ISC(WDS)/IUGG(IACS)/UNEP/UNESCO/WMO, World Glacier Monitoring Service, Zurich, Switzerland, 278 pp., publication based on database version: https://doi.org/10.5904/wgms-fog-2021-05, 2021.
Woodward, J., Sharp, M., and Arendt, A.: The influence of superimposed–ice formation on the sensitivity of glacier mass balance to climate change, Ann. Glaciol., 24, 186–190, 1997.
Yue, X., Li, Z., Zhao, J., Li, H., Wang, P., and Wang, L.: Changes in the end-of-summer snow line altitude of summer-accumulation-type glaciers in the Eastern Tien Shan Mountains from 1994 to 2016, Remote Sens., 13, 1080, https://doi.org/10.3390/rs13061080, 2021.
Short summary
Here we present summer snowline altitude (SLA) time series for 269 Arctic glaciers. Between 1984 and 2022, SLAs rose ∼ 150 m, equating to a ∼ 127 m shift per 1 °C of summer warming. SLA is most strongly correlated with annual temperature variables, highlighting their dual effect on ablation and accumulation processes. We show that SLAs are rising fastest on low-elevation glaciers and that > 50 % of the studied glaciers could have SLAs that exceed the maximum ice elevation by 2100.
Here we present summer snowline altitude (SLA) time series for 269 Arctic glaciers. Between 1984...