10,000 years of melt history of the 2015 Renland ice core, EastGreenland

Abstract. An ice core drilled in 2015 on the Renland ice cap at the eastern margin of Greenland has been inspected with regard to its melt content. The thickness of a melt layer reflects the temperature level at the time of melt generation. Hence the melt layers are an indicator of past regional summer temperatures in East Greenland, a region where paleoclimate records are sparse. Melt layers have been identified almost along the whole core, resulting in a melt record reaching back 10,000 years. By gathering additional information about melt rates as well as high-resolution densities in two shallow cores, we developed an approach to correct the annual melt content for the ice volume that gets lost by the thinning process. The result is a melt record with decadal- to centennial- scale resolution for the last two millennia, and the most accurate Holocene climate record for Eastern Greenland so far. The observed changes of annual melt rates show a warm early Holocene, with melt rates higher than in the recent past century, and minimum melting during the Little Ice Age. Current melt rates show a strong increase for the early 20th century as well as for the time since the end of the past century, with the recent 2012 extreme melting of the Greenland Ice Sheet being the strongest melt event in the past 500 years.

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Climatic history of the northeastern United States during the past 3000 years

Climate of the Past ◽

10.5194/cp-13-1355-2017 ◽

2017 ◽

Vol 13 (10) ◽

pp. 1355-1379 ◽

Cited By ~ 18

Author(s):

Jennifer R. Marlon ◽

Neil Pederson ◽

Connor Nolan ◽

Simon Goring ◽

Bryan Shuman ◽

...

Keyword(s):

Ecosystem Dynamics ◽

Ice Age ◽

Extreme Weather Events ◽

Past Century ◽

Vegetation Growth ◽

The Past ◽

Weather Events ◽

Dry Conditions ◽

History Of ◽

Paleoclimate Records

Abstract. Many ecosystem processes that influence Earth system feedbacks – vegetation growth, water and nutrient cycling, disturbance regimes – are strongly influenced by multidecadal- to millennial-scale climate variations that cannot be directly observed. Paleoclimate records provide information about these variations, forming the basis of our understanding and modeling of them. Fossil pollen records are abundant in the NE US, but cannot simultaneously provide information about paleoclimate and past vegetation in a modeling context because this leads to circular logic. If pollen data are used to constrain past vegetation changes, then the remaining paleoclimate archives in the northeastern US (NE US) are quite limited. Nonetheless, a growing number of diverse reconstructions have been developed but have not yet been examined together. Here we conduct a systematic review, assessment, and comparison of paleotemperature and paleohydrological proxies from the NE US for the last 3000 years. Regional temperature reconstructions (primarily summer) show a long-term cooling trend (1000 BCE–1700 CE) consistent with hemispheric-scale reconstructions, while hydroclimate data show gradually wetter conditions through the present day. Multiple proxies suggest that a prolonged, widespread drought occurred between 550 and 750 CE. Dry conditions are also evident during the Medieval Climate Anomaly, which was warmer and drier than the Little Ice Age and drier than today. There is some evidence for an acceleration of the longer-term wetting trend in the NE US during the past century; coupled with an abrupt shift from decreasing to increasing temperatures in the past century, these changes could have wide-ranging implications for species distributions, ecosystem dynamics, and extreme weather events. More work is needed to gather paleoclimate data in the NE US to make inter-proxy comparisons and to improve estimates of uncertainty in reconstructions.

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Changes in Eurasian glaciation during the past century: glacier mass balance and ice-core evidence

Annals of Glaciology ◽

10.3189/s0260305500012313 ◽

1997 ◽

Vol 24 ◽

pp. 283-287 ◽

Cited By ~ 2

Author(s):

Vladimir N. Mikhalenko

Keyword(s):

Mass Balance ◽

Ice Core ◽

Climatic Conditions ◽

Tien Shan ◽

The Arctic ◽

Past Century ◽

Glacier Mass Balance ◽

The Past ◽

Ice Cap ◽

Glacier Ice

Glaciers of both the Arctic and mid-latitude mountain systems within Eurasia have retreated intensively during the past century. Measured and reconstructed glacier mass balances show that glacier retreat began around the 1880s. The mean annual mass-balance value for 1880–1990 was −480 mm a−1 for glaciers with maritime climatic conditions, and −140 mm a−1 for continental glaciers. It can be concluded that warming in the Caucasus occurred during at least the last 60 years, according to the distribution of crystal sizes in an ice core from the Dzhantugan firn plateau. Temperatures measured in 1962 at 20 m on the Gregoriev ice cap, Tien Shan, were −4.2°C while in 1990 they were −2°C, a warming of 2.2°C over 28 years. Changes in the isotopic composition of glacier ice during the 20th century indicate recent and continuing warming in different regions of Eurasia. The δ18O records reveal an enrichment at the Gregoriev ice cap during the last 50 years, while surface temperatures at the Tien Shan meteorological station have increased 0.5°C since 1930.

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Trends and features of climatic changes in the past 5000 years recorded by the Dunde ice core

Annals of Glaciology ◽

10.3189/1992aog16-1-21-24 ◽

1992 ◽

Vol 16 ◽

pp. 21-24 ◽

Cited By ~ 19

Author(s):

Yao Tandong ◽

L. G. Thompson

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Climatic Changes ◽

Ice Age ◽

The Tibetan Plateau ◽

Temperature Relation ◽

The Core ◽

The Past ◽

Ice Cap ◽

The Qilian Mountains

Α δ18O record from Dunde Ice Cap, located in the Qilian mountains on the northeastern margin of the Tibetan Plateau, has been analyzed and interpreted. With an ice temperature of –7.3°C at a depth of 10 m and –4.7°C at the bottom of the ice cap, and an accumulation rate of 400 mm a−1, the Dunde core has provided interesting results. The upper part of this core, core D-l, can be easily dated by a combination of δ18O, microparticle concentration and conductivity. It can also be dated as far back as 4550 BP by counting dust layers in ice. Based on the time scale established by the above methods and on the δ18O–temperature relation, the δ18O fluctuations in the upper 120 m of the core can be interpreted as mainly due to climatic changes during the past ~ 5000 years. The warmest periods in the past ~ 5000 years in the core were found to be centered on the present, 3000, and 4100 BP, and the colder periods center around 500, 1200, 4000, and 4500 BP. It is clear from the ice-core record that the Little Ice Age was only one of many cold periods in the past, although it was the coldest period in the past 500 years.

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Fabric and texture at Siple Dome, Antarctica

Journal of Glaciology ◽

10.3189/172756505781829359 ◽

2005 ◽

Vol 51 (173) ◽

pp. 281-290 ◽

Cited By ~ 32

Author(s):

C.L. Diprinzio ◽

L.A. Wilen ◽

R.B. Alley ◽

J.J. Fitzpatrick ◽

M.K. Spencer ◽

...

Keyword(s):

Ice Core ◽

Ice Age ◽

West Antarctica ◽

Ice Flow ◽

Thin Sections ◽

Fine Grained ◽

Additional Information ◽

Siple Dome ◽

History Of ◽

Last Ice Age

AbstractPreferred c-axis orientations are present in the firn at Siple Dome, West Antarctica, and recrystallization begins as shallow as 200 m depth in ice below –20°C, based on digital analysis of c-axis fabrics, grain-sizes and other characteristics of 52 vertical thin sections prepared in the field from the kilometer-long Siple Dome ice core. The shallowest section analyzed, from 22 m, shows clustering of c axes toward the vertical. By 200 m depth, girdle fabric and other features of recrystallized ice are evident in layers (or regions), separated by layers (regions) of typically finer-grained ice lacking evidence of recrystallization. Ice from about 700–780m depth, which was deposited during the last ice age, is especially fine-grained, with strongly vertical c axes, but deeper ice shows much larger crystals and strong evidence of recrystallization. Azimuthal asymmetry of some c-axis fabrics, trends in grain-size, and other indicators reveal additional information on processes and history of ice flow at Siple Dome.

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High Arctic Holocene temperature record from the Agassiz ice cap and Greenland ice sheet evolution

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1616287114 ◽

2017 ◽

Vol 114 (23) ◽

pp. 5952-5957 ◽

Cited By ~ 63

Author(s):

Benoit S. Lecavalier ◽

David A. Fisher ◽

Glenn A. Milne ◽

Bo M. Vinther ◽

Lev Tarasov ◽

...

Keyword(s):

Air Temperature ◽

Ice Core ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Temperature Reconstruction ◽

High Arctic ◽

Early Holocene ◽

Temperature Record ◽

The Past ◽

Ice Cap

We present a revised and extended high Arctic air temperature reconstruction from a single proxy that spans the past ∼12,000 y (up to 2009 CE). Our reconstruction from the Agassiz ice cap (Ellesmere Island, Canada) indicates an earlier and warmer Holocene thermal maximum with early Holocene temperatures that are 4–5 °C warmer compared with a previous reconstruction, and regularly exceed contemporary values for a period of ∼3,000 y. Our results show that air temperatures in this region are now at their warmest in the past 6,800–7,800 y, and that the recent rate of temperature change is unprecedented over the entire Holocene. The warmer early Holocene inferred from the Agassiz ice core leads to an estimated ∼1 km of ice thinning in northwest Greenland during the early Holocene using the Camp Century ice core. Ice modeling results show that this large thinning is consistent with our air temperature reconstruction. The modeling results also demonstrate the broader significance of the enhanced warming, with a retreat of the northern ice margin behind its present position in the mid Holocene and a ∼25% increase in total Greenland ice sheet mass loss (∼1.4 m sea-level equivalent) during the last deglaciation, both of which have implications for interpreting geodetic measurements of land uplift and gravity changes in northern Greenland.

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Changes in Eurasian glaciation during the past century: glacier mass balance and ice-core evidence

Annals of Glaciology ◽

10.1017/s0260305500012313 ◽

1997 ◽

Vol 24 ◽

pp. 283-287 ◽

Cited By ~ 6

Author(s):

Vladimir N. Mikhalenko

Keyword(s):

Mass Balance ◽

Ice Core ◽

Climatic Conditions ◽

Tien Shan ◽

The Arctic ◽

Past Century ◽

Glacier Mass Balance ◽

The Past ◽

Ice Cap ◽

Glacier Ice

Glaciers of both the Arctic and mid-latitude mountain systems within Eurasia have retreated intensively during the past century. Measured and reconstructed glacier mass balances show that glacier retreat began around the 1880s. The mean annual mass-balance value for 1880–1990 was −480 mm a−1 for glaciers with maritime climatic conditions, and −140 mm a−1 for continental glaciers. It can be concluded that warming in the Caucasus occurred during at least the last 60 years, according to the distribution of crystal sizes in an ice core from the Dzhantugan firn plateau. Temperatures measured in 1962 at 20 m on the Gregoriev ice cap, Tien Shan, were −4.2°C while in 1990 they were −2°C, a warming of 2.2°C over 28 years. Changes in the isotopic composition of glacier ice during the 20th century indicate recent and continuing warming in different regions of Eurasia. The δ 18O records reveal an enrichment at the Gregoriev ice cap during the last 50 years, while surface temperatures at the Tien Shan meteorological station have increased 0.5°C since 1930.

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Trends and features of climatic changes in the past 5000 years recorded by the Dunde ice core

Annals of Glaciology ◽

10.1017/s0260305500004766 ◽

1992 ◽

Vol 16 ◽

pp. 21-24 ◽

Cited By ~ 77

Author(s):

Yao Tandong ◽

L. G. Thompson

Keyword(s):

Accumulation Rate ◽

Ice Core ◽

Climatic Changes ◽

Ice Age ◽

The Tibetan Plateau ◽

Temperature Relation ◽

The Core ◽

The Past ◽

Ice Cap ◽

The Qilian Mountains

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Volcanic eruptions recorded in an ice core from Collins Ice Cap, King George Island, Antarctica

Annals of Glaciology ◽

10.3189/172756499781821139 ◽

1999 ◽

Vol 29 ◽

pp. 121-125 ◽

Cited By ~ 5

Author(s):

Han Jiankan ◽

Xie Zichu ◽

Dai Fengnian ◽

Zhang Wanchang

Keyword(s):

Volcanic Activity ◽

Ice Core ◽

Volcanic Eruptions ◽

South Shetland Islands ◽

Past Century ◽

King George Island ◽

The Core ◽

The Past ◽

Ice Cap ◽

Eruptive Cycles

AbstractCareful mineral and structural analyses have revealed the characteristics of volcanic ash in the nine horizons of an 80.2 m ice core from Collins Ice Cap, King George Island, Antarctica.Under the assumption of steady state, the Dansgaard-Johnsen flow model was employed to date the core. The volcanic eruptive sequence established for the South Shetland Islands region since AD 1650 shows seven volcanic eruptive cycles during the past 340 years covered by the ice core. It seems that during the period 1875-1925 there was frequent volcanic activity, with perhaps many eruptions at Deception Island. The years 1650-1800 appear to have been a quiet period, followed by a more turbulent century. The past century is basically a tranquil era except for two turbulent epochs at the beginning of the century and in the 1950s-70s.Many of the volcanic eruptions in the ice-core sequence are found in the previously reported records for this region. The few that are not in the records should be further investigated. The absence of any 1967-70 eruption trace in the core suggests that this period may represent a minimum in volcanic activity.

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Improved estimates of preindustrial biomass burning reduce the magnitude of aerosol climate forcing in the Southern Hemisphere

Science Advances ◽

10.1126/sciadv.abc1379 ◽

2021 ◽

Vol 7 (22) ◽

pp. eabc1379

Author(s):

Pengfei Liu ◽

Jed O. Kaplan ◽

Loretta J. Mickley ◽

Yang Li ◽

Nathan J. Chellman ◽

...

Keyword(s):

Southern Hemisphere ◽

Radiative Forcing ◽

Ice Core ◽

Ice Cores ◽

Terrestrial Ecosystems ◽

Rapid Expansion ◽

Past Century ◽

Fire Emissions ◽

The Past ◽

Fire Activity

Fire plays a pivotal role in shaping terrestrial ecosystems and the chemical composition of the atmosphere and thus influences Earth’s climate. The trend and magnitude of fire activity over the past few centuries are controversial, which hinders understanding of preindustrial to present-day aerosol radiative forcing. Here, we present evidence from records of 14 Antarctic ice cores and 1 central Andean ice core, suggesting that historical fire activity in the Southern Hemisphere (SH) exceeded present-day levels. To understand this observation, we use a global fire model to show that overall SH fire emissions could have declined by 30% over the 20th century, possibly because of the rapid expansion of land use for agriculture and animal production in middle to high latitudes. Radiative forcing calculations suggest that the decreasing trend in SH fire emissions over the past century largely compensates for the cooling effect of increasing aerosols from fossil fuel and biofuel sources.

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