A seasonality trigger for carbon injection at the Paleocene-Eocene thermal maximum

Abstract. The Paleocene-Eocene thermal maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean-atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation reconstructions for the PETM, based on bioclimatic analysis of terrestrially-derived spore and pollen assemblages preserved in an expanded section from the Central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

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A seasonality trigger for carbon injection at the Paleocene–Eocene Thermal Maximum

Climate of the Past ◽

10.5194/cp-10-759-2014 ◽

2014 ◽

Vol 10 (2) ◽

pp. 759-769 ◽

Cited By ~ 36

Author(s):

J. S. Eldrett ◽

D. R. Greenwood ◽

M. Polling ◽

H. Brinkhuis ◽

A. Sluijs

Keyword(s):

Deep Ocean ◽

Mean Annual Temperature ◽

Ecological Change ◽

Broadleaf Forest ◽

Temperature Changes ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

Carbon Injection ◽

Summer Temperatures ◽

Central North Sea

Abstract. The Paleocene–Eocene Thermal Maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean–atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation and paleoclimate reconstructions for the PETM, based on nearest living relative analysis of terrestrially derived spore and pollen assemblages preserved in an expanded section from the central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes, and a shift to a summer-wet seasonality. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

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Deciphering the Palaeocene–Eocene thermal maximum by Granger causality test

10.21203/rs.3.rs-789514/v1 ◽

2021 ◽

Author(s):

Zeyang Liu ◽

Xiehua Ji ◽

Wenyan Luo ◽

Yujie Hu ◽

Haoran Liu

Keyword(s):

Global Warming ◽

Carbon Emission ◽

Causality Test ◽

Environmental Perturbations ◽

Causal Direction ◽

Carbon Isotope Excursion ◽

Initial Carbon ◽

Thermal Maximum ◽

Carbon Injection ◽

Permafrost Thawing

Abstract The Palaeocene–Eocene thermal maximum is a global warming period (~ 56 Ma), which is marked by a sharp negative carbon isotope excursion (CIE) that caused by the injection of massive isotopically-light carbon into the ocean-atmosphere. It is often considered that the carbon injection caused global warming. However, several studies have suggested that warming and environmental perturbations precede the onset of the CIE. Here we present Granger test to investigate the detailed mechanisms of this event. We show a shift from climate-warming driving carbon-emission scenario to a scheme in which carbon-injection causing global-warming during the CIE. The initial carbon emission might be from methane hydrates dissociation and/or permafrost thawing, possibly linked with astronomical paced warming. This change of causal direction may result from the warming feedback of the emitted carbon and additional carbon from other sources, such as volcanism, bolide impact, oxidation of marine organic matter, and wildfires burning peatlands.

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Calcium isotope composition of Morozovella over the late Paleocene–early Eocene

Geology ◽

10.1130/g48619.1 ◽

2021 ◽

Author(s):

Gabriella D. Kitch ◽

Andrew D. Jacobson ◽

Dustin T. Harper ◽

Matthew T. Hurtgen ◽

Bradley B. Sageman ◽

...

Keyword(s):

Isotope Composition ◽

Calcium Isotope ◽

Ocean Drilling Program ◽

Ocean Drilling ◽

Carbonate Ion ◽

Kinetic Isotope ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

Igneous Province ◽

North Atlantic Igneous Province

Ocean acidification (OA) during the Paleocene-Eocene thermal maximum (PETM) likely caused a biocalcification crisis. The calcium isotope composition (δ44/40Ca) of primary carbonate producers may be sensitive to OA. To test this hypothesis, we constructed the first high-resolution, high-precision planktic foraminiferal δ44/40Ca records before and across the PETM. The records employ specimens of Morozovella spp. collected from Ocean Drilling Program Sites 1209 (Shatsky Rise, Pacific Ocean) and 1263 (Walvis Ridge, Atlantic Ocean). At Site 1209, δ44/40Ca values start at –1.33‰ during the Upper Paleocene and increase to a peak of –1.15‰ immediately before the negative carbon isotope excursion (CIE) that marks the PETM onset. Values remain elevated through the PETM interval and decrease into the earliest Eocene. A shorter-term record for Site 1263 shows a similar trend, although δ44/40Ca values are on average 0.22‰ lower and decrease shortly after the CIE onset. The trends support neither diagenetic overprinting, authigenic carbonate additions, nor changes in the δ44/40Ca value of seawater. Rather, they are consistent with a kinetic isotope effect, whereby calcite δ44/40Ca values inversely correlate with precipitation rate. Geologically rapid Ca isotope shifts appear to reflect the response of Morozovella to globally forced changes in the local carbonate geochemistry of seawater. All data combined suggest that the PETM-OA event occurred near the peak of a gradual reduction in seawater carbonate ion concentrations during a time of elevated atmospheric pCO2, potentially driven by North Atlantic igneous province emplacement.

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Effect of Climate Change on Soil Erosion in a Mountainous Mediterranean Catchment (Central Pindus, Greece)

Water ◽

10.3390/w10101469 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1469 ◽

Cited By ~ 7

Author(s):

Stefanos Stefanidis ◽

Dimitrios Stathis

Keyword(s):

Climate Change ◽

Soil Erosion ◽

Potential Model ◽

Climate Model ◽

Regional Climate ◽

Baseline Period ◽

Mean Annual Temperature ◽

Temperature Changes ◽

Mountainous Catchment ◽

Precipitation And Temperature

The aim of this study was to assess soil erosion changes in the mountainous catchment of the Portaikos torrent (Central Greece) under climate change. To this end, precipitation and temperature data were derived from a high-resolution (25 × 25 km) RegCM3 regional climate model for the baseline period 1974–2000 and future period 2074–2100. Additionally, three GIS layers were generated regarding land cover, geology, and slopes in the study area, whereas erosion state was recognized after field observations. Subsequently, the erosion potential model (EPM) was applied to quantify the effects of precipitation and temperature changes on soil erosion. The results showed a decrease (−21.2%) in annual precipitation (mm) and increase (+3.6 °C) in mean annual temperature until the end of the 21st century, and the above changes are likely to lead to a small decrease (−4.9%) in soil erosion potential.

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Fast Warming Has Accelerated Snow Cover Loss during Spring and Summer across the Northern Hemisphere over the Past 52 Years (1967–2018)

Atmosphere ◽

10.3390/atmos11070728 ◽

2020 ◽

Vol 11 (7) ◽

pp. 728

Author(s):

Xuejiao Wu ◽

Yongping Shen ◽

Wei Zhang ◽

Yinping Long

Keyword(s):

Snow Cover ◽

Northern Hemisphere ◽

Spatial Scales ◽

Summer Precipitation ◽

Temperature Changes ◽

The Past ◽

Four Seasons ◽

Snow Cover Extent ◽

Summer Temperatures ◽

Substantial Decline

With snow cover changing worldwide in several worrisome ways, it is imperative to determine both the variability in snow cover in greater detail and its relationship with ongoing climate change. Here, we used the satellite-based snow cover extent (SCE) dataset of National Oceanic and Atmospheric Administration (NOAA) to detect SCE variability and its linkages to climate over the 1967–2018 periods across the Northern Hemisphere (NH). Interannually, the time series of SCE across the NH reveal a substantial decline in both spring and summer (−0.54 and −0.71 million km2/decade, respectively), and this decreasing trend corresponded with rising spring and summer temperatures over high-latitude NH regions. Among the four seasons, the temperature rise over the NH was the highest in winter (0.39 °C/decade, p < 0.01). More precipitation in winter was closely related to an increase of winter SCE in mid-latitude areas of NH. Summer precipitation over the NH increased at a significant rate (1.1 mm/decade, p < 0.01), which likely contribute to the accelerated reduction of summer’s SCE across the NH. However, seasonal sensitivity of SCE to temperature changes differed between the Eurasian and North American continents. Thus, this study provides a better understanding of seasonal SCE variability and climatic changes that occurred at regional and hemispheric spatial scales in the past 52 years.

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Late Paleocene event chronology; unconformities, not diachrony

BSGF - Earth Sciences Bulletin ◽

10.2113/171.3.367 ◽

2000 ◽

Vol 171 (3) ◽

pp. 367-378 ◽

Cited By ~ 24

Author(s):

Marie-Pierre Aubry ◽

Benjamin S. Cramer ◽

Kenneth G. Miller ◽

James D. Wright ◽

Dennis V. Kent ◽

...

Keyword(s):

Planktonic Foraminifera ◽

Calcareous Nannoplankton ◽

Lower Eocene ◽

Late Paleocene ◽

Relative Chronology ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

Unequivocal Identification ◽

Upper Paleocene ◽

Reference Section

Abstract The chronology of the events associated with the late Paleocene thermal maximum (LPTM, Chron C24r) has been established through the construction of a composite reference section that involved chemomagnetobiostratigraphic correlations and assumed minimum diachrony of biostratigraphic events. On this basis, discrepancies between correlations in different sections were explained by inferred unconformities. However, diachrony between distant sections cannot be ruled out. We report here on two geographically close sections drilled onshore New Jersey that yield different records of chemomagnetobiostratigraphic correlations in the interval representing Chron C24r. Because of their proximity ( approximately 40 km apart), diachrony of biostratigraphic events between the two sections can be ruled out. In contrast, the marked lithologic disconformities in the sections explain well the different records of events. We thus conclude that the current relative chronology for Chron C24r is firmly based and that the upper Paleocene-lower Eocene stratigraphic record yields multiple unconformities, with Subzone NP9b rarely sampled. We examine the implications that undeciphered unconformities may have on the identification of proxies for paleoceanographic reconstruction, in particular with regard to the identification of the carbon isotope excursion (CIE) that reflects a dramatic latest Paleocene disturbance of the carbon cycle. We propose biostratigraphic means (short-lived calcareous nannoplankton and planktonic foraminifera taxa) that permit the unequivocal identification of the CIE not only in the oceanic realm but also in neritic settings.

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Stratigraphic and sedimentological aspects of the worldwide distribution of Apectodinium in Paleocene/Eocene Thermal Maximum deposits

Geological Society London Special Publications ◽

10.1144/sp511-2020-46 ◽

2021 ◽

pp. SP511-2020-46

Author(s):

Christopher N. Denison

Keyword(s):

Global Warming ◽

Sea Level ◽

Environmental Changes ◽

Calcareous Nannofossil ◽

Shallow Marine ◽

Worldwide Distribution ◽

Carbon Isotope Excursion ◽

Thermal Maximum ◽

Taxonomic Changes ◽

Data Gap

AbstractThe Paleocene/Eocene Thermal Maximum (PETM) is characterized by pronounced global warming and associated environmental changes. In the more-or-less two decades since prior regional syntheses of Apectodinium distribution at the PETM, extensive biological and geochemical datasets have elucidated the effect of rising world temperatures on climate and the biome. A Carbon Isotope Excursion (CIE) that marks the Paleocene/Eocene Boundary (PEB) is associated with an acme of marine dinocysts of the genus Apectodinium in many locations. Distinctive foraminiferal and calcareous nannofossil populations may also be present.For this up-dated, dinocyst-oriented view of the PETM, data from worldwide locations have been evaluated with an emphasis on stratigraphic and sedimentological context. What has emerged is that a change in lithology is common, often to a distinctive siltstone or claystone unit, which contrasts with underlying and overlying lithotypes. This change, present in shallow marine/coastal settings and in deepwater turbidite deposits, is attributed to radical modifications of precipitation and erosional processes. An abrupt boundary carries the implication that some time (of unknowable duration) is potentially missing, which then requires caution in the interpretation of the pacing of events in relation to that boundary. In most instances an ‘abrupt’ or ‘rapid’ CIE onset can be attributed to a data gap at a hiatus, particularly in shallow shelf settings where transgression resulted from sea-level rise associated with the PETM. Truly gradational lower boundaries of the PETM interval are quite unusual, and if present, are poorly known so far. Gradational upper boundaries are more common, but erosional upper boundaries have been reported.Taxonomic changes have been made to clarify identification issues that have adversely impacted some biostratigraphic interpretations. Apectodinium hyperacanthum has been retained in Wetzeliella, its original genus. The majority of specimens previously assigned to Apectodinium hyperacanthum or Wetzeliella (Apectodinium) hyperacanthum have been re-assigned to an informal species, Apectodinium sp. 1. Dracodinium astra has been retained in its original genus as Wetzeliella astra, and is emended.

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Seismic ocean thermometry

Science ◽

10.1126/science.abb9519 ◽

2020 ◽

Vol 369 (6510) ◽

pp. 1510-1515 ◽

Cited By ~ 1

Author(s):

Wenbo Wu ◽

Zhongwen Zhan ◽

Shirui Peng ◽

Sidao Ni ◽

Jörn Callies

Keyword(s):

Deep Ocean ◽

Warming Trend ◽

Sound Waves ◽

Temperature Changes ◽

East Indian ◽

Repeating Earthquakes ◽

Basin Scale ◽

Sampling Problem ◽

Ocean Monitoring ◽

East Indian Ocean

More than 90% of the energy trapped on Earth by increasingly abundant greenhouse gases is absorbed by the ocean. Monitoring the resulting ocean warming remains a challenging sampling problem. To complement existing point measurements, we introduce a method that infers basin-scale deep-ocean temperature changes from the travel times of sound waves that are generated by repeating earthquakes. A first implementation of this seismic ocean thermometry constrains temperature anomalies averaged across a 3000-kilometer-long section in the equatorial East Indian Ocean with a standard error of 0.0060 kelvin. Between 2005 and 2016, we find temperature fluctuations on time scales of 12 months, 6 months, and ~10 days, and we infer a decadal warming trend that substantially exceeds previous estimates.

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Reduced carbon cycle resilience across the Palaeocene–Eocene Thermal Maximum

Climate of the Past ◽

10.5194/cp-14-1515-2018 ◽

2018 ◽

Vol 14 (10) ◽

pp. 1515-1527 ◽

Cited By ~ 2

Author(s):

David I. Armstrong McKay ◽

Timothy M. Lenton

Keyword(s):

Organic Carbon ◽

Carbon Cycle ◽

Deep Ocean ◽

Tipping Point ◽

Tipping Points ◽

Carbon Burial ◽

Thermal Maximum ◽

Organic Carbon Burial ◽

Carbon Release ◽

Hyperthermal Events

Abstract. Several past episodes of rapid carbon cycle and climate change are hypothesised to be the result of the Earth system reaching a tipping point beyond which an abrupt transition to a new state occurs. At the Palaeocene–Eocene Thermal Maximum (PETM) at ∼56 Ma and at subsequent hyperthermal events, hypothesised tipping points involve the abrupt transfer of carbon from surface reservoirs to the atmosphere. Theory suggests that tipping points in complex dynamical systems should be preceded by critical slowing down of their dynamics, including increasing temporal autocorrelation and variability. However, reliably detecting these indicators in palaeorecords is challenging, with issues of data quality, false positives, and parameter selection potentially affecting reliability. Here we show that in a sufficiently long, high-resolution palaeorecord there is consistent evidence of destabilisation of the carbon cycle in the ∼1.5 Myr prior to the PETM, elevated carbon cycle and climate instability following both the PETM and Eocene Thermal Maximum 2 (ETM2), and different drivers of carbon cycle dynamics preceding the PETM and ETM2 events. Our results indicate a loss of “resilience” (weakened stabilising negative feedbacks and greater sensitivity to small shocks) in the carbon cycle before the PETM and in the carbon–climate system following it. This pre-PETM carbon cycle destabilisation may reflect gradual forcing by the contemporaneous North Atlantic Volcanic Province eruptions, with volcanism-driven warming potentially weakening the organic carbon burial feedback. Our results are consistent with but cannot prove the existence of a tipping point for abrupt carbon release, e.g. from methane hydrate or terrestrial organic carbon reservoirs, whereas we find no support for a tipping point in deep ocean temperature.

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Rapid carbon injection and transient global warming during the Paleocene-Eocene thermal maximum

Netherlands Journal of Geosciences – Geologie en Mijnbouw ◽

10.1017/s0016774600023271 ◽

2008 ◽

Vol 87 (3) ◽

pp. 201-206 ◽

Cited By ~ 3

Author(s):

A. Stuijs ◽

H. Brinkhuis

Keyword(s):

Global Warming ◽

High Latitude ◽

Elevated Temperatures ◽

Hydrological Cycle ◽

Warming Trend ◽

Early Eocene ◽

Biotic Response ◽

Thermal Maximum ◽

Carbon Injection

The Paleocene-Eocene Thermal Maximum (PETM), ~55.5 Myr ago, was a geologically brief (~170 kyr) episode of globally elevated temperatures, which occurred superimposed on the long-term late Paleocene and early Eocene warming trend (Fig. 1). It was marked by a 5 – 8° C warming in both low and high-latitude regions, a perturbation of the hydrological cycle and major biotic response on land and in the oceans, including radiations, extinctions and migrations (see overviews in Bowen et al., 2006; Sluijs et al., 2007a).

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