A5009414216- Geology and Paleoclimatology Research
- Climate variability and models
- Paleontology and Stratigraphy of Fossils
- Atmospheric and Environmental Gas Dynamics
- Hydrocarbon exploration and reservoir analysis
- Geological and Geophysical Studies
- Evolution and Paleontology Studies
- Methane Hydrates and Related Phenomena
- Geochemistry and Elemental Analysis
- Species Distribution and Climate Change
- Isotope Analysis in Ecology
- Marine and coastal ecosystems
- Geological Studies and Exploration
- Geological and Geochemical Analysis
- Arctic and Antarctic ice dynamics
- Geological formations and processes
- Oceanographic and Atmospheric Processes
- Plant Water Relations and Carbon Dynamics
- Geochemistry and Geologic Mapping
- Atmospheric chemistry and aerosols
- Science and Climate Studies
- Ionosphere and magnetosphere dynamics
- Greenhouse Technology and Climate Control
- Rangeland Management and Livestock Ecology
- Scientific Research and Discoveries
University of Bristol
2019-2024
GEOMAR Helmholtz Centre for Ocean Research Kiel
2018-2024
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2022
Bjerknes Centre for Climate Research
2022
Abstract. Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required estimate the sensitivity system CO2 forcing through Earth's history. Previous GMST for latest Paleocene early Eocene (∼57 48 million years ago) span a wide range (∼9 23 °C higher than pre-industrial) prevent an accurate assessment during this extreme greenhouse interval. Using most recent data compilations, we employ multi-method experimental framework...
Abstract. We present results from an ensemble of eight climate models, each which has carried out simulations the early Eocene optimum (EECO, ∼ 50 million years ago). These have been in framework Deep-Time Model Intercomparison Project (DeepMIP; http://www.deepmip.org, last access: 10 January 2021); thus, all models configured with same paleogeographic and vegetation boundary conditions. The indicate that these non-CO2 conditions contribute between 3 5 ∘C to warmth. Compared previous...
Abstract The Weissert Event ~133 million years ago marked a profound global cooling that punctuated the Early Cretaceous greenhouse. We present modelling, high-resolution bulk organic carbon isotopes and chronostratigraphically calibrated sea surface temperature (SSTs) based on an paleothermometer (the TEX 86 proxy), which capture in semi-enclosed Weddell Sea basin, offshore Antarctica (paleolatitude ~54 °S; paleowater depth ~500 meters). document ~3–4 °C drop SST coinciding with cold end,...
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...
Abstract The paleoclimate record provides a test-bed in which climate models can be evaluated under conditions of substantial CO 2 change; however, these data are typically under-used the process model development and evaluation. Here, we use set metrics based on proxy observations to evaluate three past time periods. We find that latest CMIP6/PMIP4 ensemble mean does remarkably good job simulating global surface air temperatures periods, is improved CMIP5/PMIP3, implying modern sensitivity...
Abstract Here, we compare the ocean overturning circulation of early Eocene (47–56 Ma) in eight coupled climate model simulations from Deep‐Time Model Intercomparison Project (DeepMIP) and investigate causes observed inter‐model spread. The most common global meridional (MOC) feature these is anticlockwise bottom cell, fed by sinking Southern Ocean. In North Pacific, one (GFDL) displays strong deepwater formation (CESM) shows weak formation, while Atlantic two models show signs intermediate...
Abstract During the early to middle Eocene, a mid‐to‐high latitudinal position and enhanced hydrological cycle in Australia would have contributed wetter “greener” Australian continent where today arid semi‐arid climates dominate. Here, we revisit 12 southern plant megafossil sites from Eocene generate temperature, precipitation, seasonality paleoclimate estimates, net primary productivity (NPP), vegetation type, based on paleobotanical proxies compare them global climate models. Temperature...
Abstract The simulation of Sahel rainfall and its onset during the West African Monsoon (WAM) remains a challenge for current state-of-the-art climate models due to their persistent biases, especially in tropical Atlantic region. Here we show that improved representation Cold Tongue (ACT) development is essential more realistic seasonal evolution WAM, which further inland migration precipitation maximum. observed marked relationship between ACT only can be reproduced by model, Kiel Climate...
Abstract Estimates of global mean near‐surface air temperature (global SAT) for the Cenozoic era rely largely on paleo‐proxy data deep‐sea (DST), with assumption that changes in SAT covary DST) and sea‐surface SST). We tested validity this by analyzing relationship between SST, SAT, DST using 25 different model simulations from Deep‐Time Model Intercomparison Project simulating early Eocene Climatic Optimum (EECO) varying CO 2 levels. Similar to modern situation, we find limited spatial...
Abstract The timing and causative factors underlying the Asian summer monsoon initiation remain contentious as recent proxy data modeling studies suggested existence of a wet-dry monsoon-like climate from Cretaceous period. Leveraging an ensemble deep-time simulations focused on early Eocene (DeepMIP-Eocene), we show that wet season was notably weaker shorter than present-day in absence elevated heat source like Tibetan Plateau. deficient upper-tropospheric meridional temperature gradient...
Abstract. We present results from an ensemble of seven climate models, each which has carried out simulations the early Eocene optimum (EECO, ~ 50 million years ago). These have been in framework DeepMIP (www.deepmip.org), and as such all models configured with identical paleogeographic vegetation boundary conditions. The indicate that these non-CO2 conditions contribute between 3 5 °C to warmth. Compared previous studies, show reduced spread global mean surface temperature response across...
Abstract Inconsistencies in the Eocene climates of East Asia have been revealed both geological studies and simulations. Several earlier reconstructions showed an arid zonal band mid‐latitude China, but others a humid climate same region. Moreover, previous modeling demonstrated that models can simulate scenarios China. Therefore, it is essential to investigate cause this model spread. We conducted series experiments using Norwegian Earth System Model 1‐F examined impact mountains Southern...
Abstract. Extensive black shale deposits formed in the Early Cretaceous South Atlantic, supporting notion that this emerging ocean basin was a globally important site of organic carbon burial. The magnitude burial marine basins is known to be controlled by various tectonic, oceanographic, hydrological, and climatic processes acting on different temporal spatial scales, nature relative importance which are poorly understood for young Atlantic. Here we present new bulk molecular geochemical...
The early Eocene (∼56-48 Myr ago) is characterized by high CO
Abstract The total meridional heat transport (MHT) is relatively stable across different climates. Nevertheless, the strength of individual processes contributing to are not stable. Here we investigate MHT and its main components especially in atmosphere, five coupled climate model simulations from Deep‐Time Model Intercomparison Project (DeepMIP). These target early Eocene climatic optimum, a geological time period with high CO 2 concentrations, analog upper range end‐of‐century...
ABSTRACT Upper Devonian and Lower–Middle Mississippian strata of the North American midcontinent are ubiquitously fine-grained silt-rich, comprising both so-called shale as well argillaceous limestone (or calcareous siltstone) that accumulated in Laurentian epeiric sea. Although long recognized recording marine deposition, origin transport siliciclastic material these units remains enigmatic because they do not connect to any proximal deltaic feeder systems. Here, we present new data on...
Abstract. Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required estimate the sensitivity system CO2 forcing during geological record. GMST from latest Paleocene early Eocene (~ 57 48 million years ago) span a wide range 9 23 °C higher than pre-industrial) prevent an accurate assessment this extreme greenhouse interval. Here, we develop multi-method experimental framework calculate three target intervals: 1) Ma), 2)...
Earth's hydrological cycle is expected to intensify in response global warming, with a 'wet-gets-wetter, dry-gets-drier' anticipated. The subtropics (~15-30°N/S) are predicted become drier, yet proxy evidence from past warm climates suggests these regions may be characterised by wetter conditions. Here we use an integrated data-modelling approach reconstruct global- and regional-scale rainfall patterns during the early Eocene (~48-56 million years ago), emphasis on subtropics. Model-derived...
Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required estimate the sensitivity system CO2 forcing during geological record. GMST from latest Paleocene early Eocene (~57 48 million years ago) span a wide range (~9 23°C higher than pre-industrial) prevent an accurate assessment this extreme greenhouse interval. Here, we develop multi-method experimental framework calculate three target intervals: 1) Ma), 2)...