Global warming in the pipeline

Oxford Open Climate Change, Journal Year: 2023, Volume and Issue: 3(1)

Published: Jan. 1, 2023

Abstract Improved knowledge of glacial-to-interglacial global temperature change yields Charney (fast-feedback) equilibrium climate sensitivity 1.2 ± 0.3°C (2σ) per W/m2, which is 4.8°C 1.2°C for doubled CO2. Consistent analysis over the full Cenozoic era—including ‘slow’ feedbacks by ice sheets and trace gases—supports this implies that CO2 was 300–350 ppm in Pliocene about 450 at transition to a nearly ice-free planet, exposing unrealistic lethargy sheet models. Equilibrium warming today’s GHG amount 10°C, reduced 8°C human-made aerosols. not ‘committed’ warming; rapid phaseout emissions would prevent most from occurring. However, decline aerosol since 2010 should increase 1970–2010 rate 0.18°C decade post-2010 least 0.27°C decade. Thus, under present geopolitical approach emissions, will exceed 1.5°C 2020s 2°C before 2050. Impacts on people nature accelerate as increases hydrologic (weather) extremes. The enormity consequences demands return Holocene-level temperature. Required actions include: (1) increasing price accompanied development abundant, affordable, dispatchable clean energy, (2) East-West cooperation way accommodates developing world needs, (3) intervention with Earth’s radiation imbalance phase down massive ‘geo-transformation’ climate. Current political crises an opportunity reset, especially if young can grasp their situation.

Language: Английский

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Toward a Cenozoic history of atmospheric CO ₂

Science, Journal Year: 2023, Volume and Issue: 382(6675)

Published: Dec. 7, 2023

The geological record encodes the relationship between climate and atmospheric carbon dioxide (CO 2 ) over long short timescales, as well potential drivers of evolutionary transitions. However, reconstructing CO beyond direct measurements requires use paleoproxies herein lies challenge, proxies differ in their assumptions, degree understanding, even reconstructed values. In this study, we critically evaluated, categorized, integrated available to create a high-fidelity transparently constructed spanning past 66 million years. This newly provides clearer evidence for higher Earth system sensitivity role thresholds biological cryosphere evolution.

Language: Английский

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A 485-million-year history of Earth’s surface temperature

Science, Journal Year: 2024, Volume and Issue: 385(6715)

Published: Sept. 19, 2024

A long-term record of global mean surface temperature (GMST) provides critical insight into the dynamical limits Earth's climate and complex feedbacks between broader Earth system. Here, we present PhanDA, a reconstruction GMST over past 485 million years, generated by statistically integrating proxy data with model simulations. PhanDA exhibits large range GMST, spanning 11° to 36°C. Partitioning states indicates that more time was spent in warmer rather than colder climates reveals consistent latitudinal gradients within each state. There is strong correlation atmospheric carbon dioxide (CO

Language: Английский

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Global and Zonal‐Mean Hydrological Response to Early Eocene Warmth

Paleoceanography and Paleoclimatology, Journal Year: 2023, Volume and Issue: 38(6)

Published: June 1, 2023

Abstract Earth's hydrological cycle is expected to intensify in response global warming, with a “wet‐gets‐wetter, dry‐gets‐drier” anticipated over the ocean. Subtropical regions (∼15°–30°N/S) are predicted become drier, yet proxy evidence from past warm climates suggests these may be characterized by wetter conditions. Here we use an integrated data‐modeling approach reconstruct and zonal‐mean rainfall patterns during early Eocene (∼56–48 million years ago). The Deep‐Time Model Intercomparison Project (DeepMIP) model ensemble indicates that mid‐ (30°–60°N/S) high‐latitudes (>60°N/S) thermodynamically dominated warming overall tropical band (0°–15°N/S) also conditions, several DeepMIP models simulating narrowing of Inter‐Tropical Convergence Zone. However, latter not evident data. subtropics negative precipitation‐evaporation anomalies (i.e., drier conditions) models, but there surprisingly large inter‐model variability mean annual precipitation (MAP). Intriguingly, find weaker meridional temperature gradients (e.g., CESM, GFDL) reduction subtropical moisture divergence, leading increase MAP. These simulations agree more closely our new proxy‐derived reconstructions other key climate metrics imply was reduced divergence. If gradient even than suggested those circulation‐induced changes have outcompeted thermodynamic changes, subtropics. This highlights importance accurately reconstructing zonal when patterns.

Language: Английский

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The terrestrial end-Permian mass extinction in the paleotropics postdates the marine extinction

Science Advances, Journal Year: 2024, Volume and Issue: 10(5)

Published: Jan. 31, 2024

The end-Permian mass extinction was the most severe ecological event during Phanerozoic and has long been presumed contemporaneous across terrestrial marine realms with global environmental deterioration triggered by Siberian Traps Large Igneous Province. We present high-precision zircon U-Pb geochronology chemical abrasion-isotope dilution-thermal ionization spectrometry technique on tuffs from to transitional coastal settings in Southwest China, which reveals a protracted collapse of Cathaysian rainforest beginning after onset extinction. Integrated high-resolution coeval successions, our results suggest that occurred diachronously latitude, at high latitudes late Changhsingian progressing tropics early Induan, spanning duration nearly 1 million years. This latitudinal age gradient may have related variations surface warming more degraded conditions higher contributing rates.

Language: Английский

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Oxygen rise in the tropical upper ocean during the Paleocene-Eocene Thermal Maximum

Science, Journal Year: 2024, Volume and Issue: 383(6684), P. 727 - 731

Published: Feb. 15, 2024

The global ocean's oxygen inventory is declining in response to warming, but the future of low-oxygen tropics uncertain. We report new evidence for tropical oxygenation during Paleocene-Eocene Thermal Maximum (PETM), a warming event that serves as geologic analog anthropogenic warming. Foraminifera-bound nitrogen isotopes indicate North Pacific oxygen-deficient zone contracted PETM. A concomitant increase foraminifera size implies availability rose shallow subsurface throughout Pacific. These changes are consistent with ocean model simulations which decline biological productivity allows rise even declines. may have helped avoid mass extinction

Language: Английский

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Paleoclimate data assimilation: Principles and prospects

Science China Earth Sciences, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 9, 2025

Language: Английский

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Polar amplification of orbital-scale climate variability in the early Eocene greenhouse world

Climate of the past, Journal Year: 2024, Volume and Issue: 20(6), P. 1303 - 1325

Published: June 12, 2024

Abstract. Climate variability is typically amplified towards polar regions. The underlying causes, notably albedo and humidity changes, are challenging to accurately quantify with observations or models, thus hampering projections of future amplification. Polar amplification reconstructions from the ice-free early Eocene (∼56–48 Ma) can exclude ice effects, but required tropical temperature records for resolving timescales shorter than multi-million years lacking. Here, we reconstruct sea surface by presenting an up ∼4 kyr resolution biomarker-based record Ocean Drilling Program (ODP) Site 959, located in Atlantic Ocean. This shows warming across multiple orbitally paced carbon cycle perturbations, coeval high-latitude-derived deep-ocean bottom waters, showing that these events represent transient global (hyperthermals). implies orbital forcing caused through feedbacks. Importantly, was a factor 1.7–2.3 compared ocean, corroborating available long-term estimates. fast atmospheric feedback processes controlled meridional gradients on year, as well orbital, during Eocene. Our combined have several other implications. First, our somewhat larger same metric fully coupled simulations (1.1–1.3), suggesting models slightly underestimate non-ice-related – hydrological feedbacks cause climate change. Second, even outside hyperthermals, find synchronous eccentricity-forced tropics deep ocean mean 0.7 °C, which requires significant pCO2. We hypothesize responsible independent ice, snow, frost-related might play important role Phanerozoic orbital-scale throughout geological time, including Pleistocene glacial–interglacial variability.

Language: Английский

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Spatial and Temporal Patterns in Petrogenic Organic Carbon Mobilization During the Paleocene‐Eocene Thermal Maximum

Paleoceanography and Paleoclimatology, Journal Year: 2024, Volume and Issue: 39(2)

Published: Jan. 31, 2024

Abstract The Paleocene‐Eocene Thermal Maximum (PETM) was a transient global warming event and is recognized in the geologic record by prolonged negative carbon isotope excursion (CIE). onset of CIE due to rapid influx 13 C‐depleted into ocean‐atmosphere system. However, mechanisms required sustain remains unclear. Enhanced mobilization oxidation petrogenic organic (OC petro ) has been invoked explain elevated atmospheric dioxide concentrations after CIE. existing evidence limited mid‐latitudes subtropics. Here, we determine whether: (a) enhanced subsequent burial OC marine sediments phenomenon; (b) whether it occurred throughout PETM. To achieve this, utilize lipid biomarker approach trace quantify compilation PETM‐aged shallow sites ( n = 7, including five new sites). Our results confirm that mass accumulation rates (MARs) increased within subtropics during PETM, consistent with higher physical erosion intense episodic rainfall events. High‐latitude do not exhibit drastic changes source PETM MARs increase slightly or remain stable, perhaps more stable hydrological regime. Crucially, also demonstrate remained recovery phase Although likely an important positive feedback mechanism show this both spatially temporally variable.

Language: Английский

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Orbital modulation of an intensified hydrological cycle during the Paleocene-Eocene Thermal Maximum

Earth and Planetary Science Letters, Journal Year: 2024, Volume and Issue: 635, P. 118693 - 118693

Published: April 4, 2024

Language: Английский

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