1.36 million years of Mediterranean forest refugium dynamics in response to glacial–interglacial cycle strength

The sediment record from Lake Ohrid (Southwestern Balkans) represents the longest continuous lake archive in Europe, extending back to 1.36 Ma. We reconstruct the vegetation history based on pollen analysis of the DEEP core to reveal changes in vegetation cover and forest diversity during glacial–interglacial (G–IG) cycles and early basin development. The earliest lake phase saw a significantly different composition rich in relict tree taxa and few herbs. Subsequent establishment of a permanent steppic herb association around 1.2 Ma implies a threshold response to changes in moisture availability and temperature and gradual adjustment of the basin morphology. A change in the character of G–IG cycles during the Early–Middle Pleistocene Transition is reflected in the record by reorganization of the vegetation from obliquity- to eccentricity-paced cycles. Based on a quantitative analysis of tree taxa richness, the first large-scale decline in tree diversity occurred around 0.94 Ma. Subsequent variations in tree richness were largely driven by the amplitude and duration of G–IG cycles. Significant tree richness declines occurred in periods with abundant dry herb associations, pointing to aridity affecting tree population survival. Assessment of long-term legacy effects between global climate and regional vegetation change reveals a significant influence of cool interglacial conditions on subsequent glacial vegetation composition and diversity. This effect is contrary to observations at high latitudes, where glacial intensity is known to control subsequent interglacial vegetation, and the evidence demonstrates that the Lake Ohrid catchment functioned as a refugium for both thermophilous and temperate tree species.

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Complexity revealed in the greening of the Arctic

10.32942/osf.io/mzyjk ◽

2019 ◽

Cited By ~ 5

Author(s):

Isla Heather Myers-Smith ◽

Jeffrey T. Kerby ◽

Gareth K. Phoenix ◽

Jarle Werner Bjerke ◽

Howard E. Epstein ◽

...

Keyword(s):

Global Climate Change ◽

Large Scale ◽

Vegetation Change ◽

Global Climate ◽

The Arctic ◽

Future Research ◽

Arctic Vegetation ◽

In Situ Data ◽

Underlying Causes

As the Arctic warms, vegetation is responding and satellite measures indicate widespread greening at high latitudes. This ‘greening of the Arctic’ is among the world’s most significant large-scale ecological responses to global climate change. However, a consensus is emerging that the underlying causes and future dynamics of so-called Arctic greening and browning trends are more complex, variable, and inherently scale dependent than previously thought. Here, we summarize the complexities of observing and interpreting high-latitude greening to identify key priorities for future research. Incorporating satellite and proximal remote sensing with in-situ data, while accounting for uncertainties and scale issues will advance the study of past, present, and future Arctic vegetation change.

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Estimating CO2 Emissions from Large Scale Coal-Fired Power Plants Using OCO-2 Observations and Emission Inventories

Atmosphere ◽

10.3390/atmos12070811 ◽

2021 ◽

Vol 12 (7) ◽

pp. 811

Author(s):

Yaqin Hu ◽

Yusheng Shi

Keyword(s):

Power Plant ◽

Co2 Emissions ◽

Atmospheric Carbon Dioxide ◽

Power Plants ◽

Large Scale ◽

Global Climate ◽

Gaussian Model ◽

Point Sources ◽

Emission Inventories ◽

Bottom Up

The concentration of atmospheric carbon dioxide (CO2) has increased rapidly worldwide, aggravating the global greenhouse effect, and coal-fired power plants are one of the biggest contributors of greenhouse gas emissions in China. However, efficient methods that can quantify CO2 emissions from individual coal-fired power plants with high accuracy are needed. In this study, we estimated the CO2 emissions of large-scale coal-fired power plants using Orbiting Carbon Observatory-2 (OCO-2) satellite data based on remote sensing inversions and bottom-up methods. First, we mapped the distribution of coal-fired power plants, displaying the total installed capacity, and identified two appropriate targets, the Waigaoqiao and Qinbei power plants in Shanghai and Henan, respectively. Then, an improved Gaussian plume model method was applied for CO2 emission estimations, with input parameters including the geographic coordinates of point sources, wind vectors from the atmospheric reanalysis of the global climate, and OCO-2 observations. The application of the Gaussian model was improved by using wind data with higher temporal and spatial resolutions, employing the physically based unit conversion method, and interpolating OCO-2 observations into different resolutions. Consequently, CO2 emissions were estimated to be 23.06 ± 2.82 (95% CI) Mt/yr using the Gaussian model and 16.28 Mt/yr using the bottom-up method for the Waigaoqiao Power Plant, and 14.58 ± 3.37 (95% CI) and 14.08 Mt/yr for the Qinbei Power Plant, respectively. These estimates were compared with three standard databases for validation: the Carbon Monitoring for Action database, the China coal-fired Power Plant Emissions Database, and the Carbon Brief database. The comparison found that previous emission inventories spanning different time frames might have overestimated the CO2 emissions of one of two Chinese power plants on the two days that the measurements were made. Our study contributes to quantifying CO2 emissions from point sources and helps in advancing satellite-based monitoring techniques of emission sources in the future; this helps in reducing errors due to human intervention in bottom-up statistical methods.

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Dynamic variations in salinity and potassium grade of a potassium-rich brine deposit in Lop Nor basin, China

Scientific Reports ◽

10.1038/s41598-021-82958-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Lichun Ma ◽

Kai Wang ◽

Yu Zhang ◽

Qingfeng Tang ◽

Hui Yan

Keyword(s):

Large Scale ◽

Sustainable Use ◽

Potassium Sulfate ◽

Middle Pleistocene ◽

Underground Brine ◽

Average Decrease ◽

Rational Development ◽

Mining History ◽

Before And After ◽

Lop Nor

AbstractThe Quaternary Lop Nor playa is the largest production base of potassium sulfate in the world. It has a mining history of more than 10 years, and its share in the Chinese potassium sulfate market is about 50% to-date. In this basin, the high-salinity potassium-rich brines are mainly contained in Middle Pleistocene–Holocene glauberite strata. Based on the monitoring of the underground brine table and geochemical analysis, this study reveals variations in the underground brine table and potassium-bearing grade before and after large-scale mining in the Lop Nor potash deposit. The results showed that the underground brine table and potassium sulfate grade decreased by varying degrees over sub-mineral areas after large-scale mining. The underground brine table declined by 8.5 m, on average, in the Luobei depression, by 6.4 m in the Tenglong platform and by 1.9 m in the Xinqing platform. However, the potassium-bearing grade showed the different trend. The Tenglong platform had the largest decline with average decreases in layers W1, W2 and W3 of 18.2%, 13.0% and 24.8%, respectively. In the Xinqing platform, the average decrease in layersW2 and W3 were 17.4% and 16.0% respectively. The Luobei depression decreases were relatively small (W1, W2 and W3 decreased 4.3%, 4.2% and 3.1%, respectively). This research provides a theoretical basis for the rational development and sustainable use of the potassium-rich brines in the Lop Nor basin.

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Global climatology and trends in convective environments from ERA5 and rawinsonde data

npj Climate and Atmospheric Science ◽

10.1038/s41612-021-00190-x ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Mateusz Taszarek ◽

John T. Allen ◽

Mattia Marchio ◽

Harold E. Brooks

Keyword(s):

Large Scale ◽

Climate Models ◽

Global Climate ◽

Convective Available Potential Energy ◽

Global Climate Models ◽

Convective Precipitation ◽

The Past ◽

The Tropics ◽

Rawinsonde Data

AbstractGlobally, thunderstorms are responsible for a significant fraction of rainfall, and in the mid-latitudes often produce extreme weather, including large hail, tornadoes and damaging winds. Despite this importance, how the global frequency of thunderstorms and their accompanying hazards has changed over the past 4 decades remains unclear. Large-scale diagnostics applied to global climate models have suggested that the frequency of thunderstorms and their intensity is likely to increase in the future. Here, we show that according to ERA5 convective available potential energy (CAPE) and convective precipitation (CP) have decreased over the tropics and subtropics with simultaneous increases in 0–6 km wind shear (BS06). Conversely, rawinsonde observations paint a different picture across the mid-latitudes with increasing CAPE and significant decreases to BS06. Differing trends and disagreement between ERA5 and rawinsondes observed over some regions suggest that results should be interpreted with caution, especially for CAPE and CP across tropics where uncertainty is the highest and reliable long-term rawinsonde observations are missing.

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On the geophysical processes impacting palaeo-sea-level observations

Geoscience Letters ◽

10.1186/s40562-021-00184-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Yusuke Yokoyama ◽

Anthony Purcell

Keyword(s):

Sea Level ◽

Large Scale ◽

Global Climate ◽

Sea Level Change ◽

Sea Level Changes ◽

Factors Affecting ◽

Ice Volume ◽

Level Change ◽

Recent Developments ◽

Geophysical Processes

AbstractPast sea-level change represents the large-scale state of global climate, reflecting the waxing and waning of global ice sheets and the corresponding effect on ocean volume. Recent developments in sampling and analytical methods enable us to more precisely reconstruct past sea-level changes using geological indicators dated by radiometric methods. However, ice-volume changes alone cannot wholly account for these observations of local, relative sea-level change because of various geophysical factors including glacio-hydro-isostatic adjustments (GIA). The mechanisms behind GIA cannot be ignored when reconstructing global ice volume, yet they remain poorly understood within the general sea-level community. In this paper, various geophysical factors affecting sea-level observations are discussed and the details and impacts of these processes on estimates of past ice volumes are introduced.

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Joint Impacts of Drought and Habitat Fragmentation on Native Bee Assemblages in a California Biodiversity Hotspot

Insects ◽

10.3390/insects12020135 ◽

2021 ◽

Vol 12 (2) ◽

pp. 135

Author(s):

Keng-Lou James Hung ◽

Sara S. Sandoval ◽

John S. Ascher ◽

David A. Holway

Keyword(s):

Habitat Fragmentation ◽

Large Scale ◽

Global Climate ◽

Relative Magnitude ◽

Urban Environments ◽

Floral Resources ◽

Severe Drought ◽

Drought Event ◽

Fragmented Habitat ◽

Native Bee

Global climate change is causing more frequent and severe droughts, which could have serious repercussions for the maintenance of biodiversity. Here, we compare native bee assemblages collected via bowl traps before and after a severe drought event in 2014 in San Diego, California, and examine the relative magnitude of impacts from drought in fragmented habitat patches versus unfragmented natural reserves. Bee richness and diversity were higher in assemblages surveyed before the drought compared to those surveyed after the drought. However, bees belonging to the Lasioglossum subgenus Dialictus increased in abundance after the drought, driving increased representation by small-bodied, primitively eusocial, and generalist bees in post-drought assemblages. Conversely, among non-Dialictus bees, post-drought years were associated with decreased abundance and reduced representation by eusocial species. Drought effects were consistently greater in reserves, which supported more bee species, than in fragments, suggesting that fragmentation either had redundant impacts with drought, or ameliorated effects of drought by enhancing bees’ access to floral resources in irrigated urban environments. Shifts in assemblage composition associated with drought were three times greater compared to those associated with habitat fragmentation, highlighting the importance of understanding the impacts of large-scale climatic events relative to those associated with land use change.

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A new world natural vegetation map for global change studies

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652008000200017 ◽

2008 ◽

Vol 80 (2) ◽

pp. 397-408 ◽

Cited By ~ 31

Author(s):

David M. Lapola ◽

Marcos D. Oyama ◽

Carlos A. Nobre ◽

Gilvan Sampaio

Keyword(s):

Large Scale ◽

New World ◽

Climate Models ◽

Global Climate ◽

Horizontal Resolution ◽

Vegetation Classification ◽

Natural Vegetation ◽

Global Climate Models ◽

Vegetation Map ◽

Vegetation Maps

We developed a new world natural vegetation map at 1 degree horizontal resolution for use in global climate models. We used the Dorman and Sellers vegetation classification with inclusion of a new biome: tropical seasonal forest, which refers to both deciduous and semi-deciduous tropical forests. SSiB biogeophysical parameters values for this new biome type are presented. Under this new vegetation classification we obtained a consensus map between two global natural vegetation maps widely used in climate studies. We found that these two maps assign different biomes in ca. 1/3 of the continental grid points. To obtain a new global natural vegetation map, non-consensus areas were filled according to regional consensus based on more than 100 regional maps available on the internet. To minimize the risk of using poor quality information, the regional maps were obtained from reliable internet sources, and the filling procedure was based on the consensus among several regional maps obtained from independent sources. The new map was designed to reproduce accurately both the large-scale distribution of the main vegetation types (as it builds on two reliable global natural vegetation maps) and the regional details (as it is based on the consensus of regional maps).

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A trait-based approach to assess climate change sensitivity of freshwater invertebrates across Swedish ecoregions

Current Zoology ◽

10.1093/czoolo/60.2.221 ◽

2014 ◽

Vol 60 (2) ◽

pp. 221-232 ◽

Cited By ~ 11

Author(s):

Leonard Sandin ◽

Astrid Schmidt-Kloiber ◽

Jens-Christian Svenning ◽

Erik Jeppesen ◽

Nikolai Friberg

Keyword(s):

Climate Change ◽

Global Climate Change ◽

Large Scale ◽

Global Climate ◽

Species Traits ◽

Freshwater Ecosystems ◽

Biological Data ◽

Conservation Strategies ◽

Measured Temperature ◽

Buffer Strips

Abstract Freshwater habitats and organisms are among the most threatened on Earth, and freshwater ecosystems have been subject to large biodiversity losses. We developed a Climate Change Sensitivity (CCS) indicator based on trait information for a selection of stream- and lake-dwelling Ephemeroptera, Plecoptera and Trichoptera taxa. We calculated the CCS scores based on ten species traits identified as sensitive to global climate change. We then assessed climate change sensitivity between the six main ecoregions of Sweden as well as the three Swedish regions based on Illies. This was done using biological data from 1, 382 stream and lake sites where we compared large-scale (ecoregional) patterns in climate change sensitivity with potential future exposure of these ecosystems to increased temperatures using ensemble-modelled future changes in air temperature. Current (1961~1990) measured temperature and ensemble-modelled future (2100) temperature showed an increase from the northernmost towards the southern ecoregions, whereas the predicted temperature change increased from south to north. The CCS indicator scores were highest in the two northernmost boreal ecoregions where we also can expect the largest global climate change-induced increase in temperature, indicating an unfortunate congruence of exposure and sensitivity to climate change. These results are of vital importance when planning and implementing management and conservation strategies in freshwater ecosystems, e.g., to mitigate increased temperatures using riparian buffer strips. We conclude that traits information on taxa specialization, e.g., in terms of feeding specialism or taxa having a preference for high altitudes as well as sensitivity to changes in temperature are important when assessing the risk from future global climate change to freshwater ecosystems.

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Climate SPHINX: evaluating the impact of resolution and stochastic physics parameterisations in the EC-Earth global climate model

Geoscientific Model Development ◽

10.5194/gmd-10-1383-2017 ◽

2017 ◽

Vol 10 (3) ◽

pp. 1383-1402 ◽

Cited By ~ 35

Author(s):

Paolo Davini ◽

Jost von Hardenberg ◽

Susanna Corti ◽

Hannah M. Christensen ◽

Stephan Juricke ◽

...

Keyword(s):

High Resolution ◽

Large Scale ◽

Climate Model ◽

Global Climate ◽

Rainfall Variability ◽

Global Climate Model ◽

Small Scale ◽

Low Resolution ◽

The Impact ◽

Stochastic Physics

Abstract. The Climate SPHINX (Stochastic Physics HIgh resolutioN eXperiments) project is a comprehensive set of ensemble simulations aimed at evaluating the sensitivity of present and future climate to model resolution and stochastic parameterisation. The EC-Earth Earth system model is used to explore the impact of stochastic physics in a large ensemble of 30-year climate integrations at five different atmospheric horizontal resolutions (from 125 up to 16 km). The project includes more than 120 simulations in both a historical scenario (1979–2008) and a climate change projection (2039–2068), together with coupled transient runs (1850–2100). A total of 20.4 million core hours have been used, made available from a single year grant from PRACE (the Partnership for Advanced Computing in Europe), and close to 1.5 PB of output data have been produced on SuperMUC IBM Petascale System at the Leibniz Supercomputing Centre (LRZ) in Garching, Germany. About 140 TB of post-processed data are stored on the CINECA supercomputing centre archives and are freely accessible to the community thanks to an EUDAT data pilot project. This paper presents the technical and scientific set-up of the experiments, including the details on the forcing used for the simulations performed, defining the SPHINX v1.0 protocol. In addition, an overview of preliminary results is given. An improvement in the simulation of Euro-Atlantic atmospheric blocking following resolution increase is observed. It is also shown that including stochastic parameterisation in the low-resolution runs helps to improve some aspects of the tropical climate – specifically the Madden–Julian Oscillation and the tropical rainfall variability. These findings show the importance of representing the impact of small-scale processes on the large-scale climate variability either explicitly (with high-resolution simulations) or stochastically (in low-resolution simulations).

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Grassland fire ecology has roots in the late Miocene

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1809758115 ◽

2018 ◽

Vol 115 (48) ◽

pp. 12130-12135 ◽

Cited By ~ 15

Author(s):

Allison T. Karp ◽

Anna K. Behrensmeyer ◽

Katherine H. Freeman

Keyword(s):

Late Miocene ◽

Fire Ecology ◽

Vegetation Change ◽

Global Climate ◽

Indian Subcontinent ◽

Strong Association ◽

Feedback System ◽

Terrestrial Vegetation ◽

Precipitation Seasonality ◽

Seasonal Extremes

That fire facilitated the late Miocene C4grassland expansion is widely suspected but poorly documented. Fire potentially tied global climate to this profound biosphere transition by serving as a regional-to-local driver of vegetation change. In modern environments, seasonal extremes in moisture amplify the occurrence of fire, disturbing forest ecosystems to create niche space for flammable grasses, which in turn provide fuel for frequent fires. On the Indian subcontinent, C4expansion was accompanied by increased seasonal extremes in rainfall (evidenced by δ18Ocarbonate), which set the stage for fuel accumulation and fire-linked clearance during wet-to-dry seasonal transitions. Here, we test the role of fire directly by examining the abundance and distribution patterns of fire-derived polycyclic aromatic hydrocarbons (PAHs) and terrestrial vegetation signatures inn-alkane carbon isotopes from paleosol samples of the Siwalik Group (Pakistan). Two million years before the C4grassland transition, fire-derived PAH concentrations increased as conifer vegetation declined, as indicated by a decrease in retene. This early increase in molecular fire signatures suggests a transition to more fire-prone vegetation such as a C3grassland and/or dry deciduous woodland. Between 8.0 and 6.0 million years ago, fire, precipitation seasonality, and C4-grass dominance increased simultaneously (within resolution) as marked by sharp increases in fire-derived PAHs, δ18Ocarbonate, and13C enrichment inn-alkanes diagnostic of C4grasses. The strong association of evidence for fire occurrence, vegetation change, and landscape opening indicates that a dynamic fire–grassland feedback system was both a necessary precondition and a driver for grassland ecology during the first emergence of C4grasslands.

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