Glaciation: A Very Short Introduction

2018 ◽  
Author(s):  
David J. A. Evans
Keyword(s):  
Sea Level ◽  
Fresh Water ◽  
Ice Sheets ◽  
Earth System ◽  
Short Introduction ◽  
Depositional Processes ◽  
The Earth ◽  
Global Sea Level

Vast, majestic, and often stunningly beautiful, glaciers lock up some 10 per cent of the world’s fresh water. These great bodies of ice play an important part in the Earth system, carving landscapes and influencing climate on regional and hemispheric scales, as well as having a significant impact on global sea level. Glaciation: A Very Short Introduction offers an overview of glaciers and ice sheets as systems, considering the role of geomorphology and sedimentology in studying them, and their impacts on our planet in terms of erosional and depositional processes. Looking at our glaciers today, and their ongoing processes, it considers the extent to which we can use this knowledge in reconstructing and interpreting ancient glacial landscapes.

scholarly journals Icy Interactions

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Jeremy Fyke ◽  
Olga Sergienko ◽  
Marcus L�fverstr�m ◽  
Stephen Price ◽  
Jan Lenaerts
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheets ◽  
Earth System ◽  
Complex Interactions ◽  
The Earth

Complex interactions between ice sheets and other components of the Earth system determine how ice sheets contribute to sea level rise.

scholarly journals Reviews and syntheses: Flying the satellite into your model: on the role of observation operators in constraining models of the Earth system and the carbon cycle

2017 ◽  
Vol 14 (9) ◽  
pp. 2343-2357 ◽  
Author(s):  
Thomas Kaminski ◽  
Pierre-Philippe Mathieu
Keyword(s):  
Data Assimilation ◽  
Carbon Cycle ◽  
Automatic Differentiation ◽  
Satellite Observations ◽  
Spectral Radiance ◽  
Special Focus ◽  
Earth System ◽  
The Earth ◽  
Retrieval Scheme

Abstract. The vehicles that fly the satellite into a model of the Earth system are observation operators. They provide the link between the quantities simulated by the model and the quantities observed from space, either directly (spectral radiance) or indirectly estimated through a retrieval scheme (biogeophysical variables). By doing so, observation operators enable modellers to properly compare, evaluate, and constrain their models with the model analogue of the satellite observations. This paper provides the formalism and a few examples of how observation operators can be used in combination with data assimilation techniques to better ingest satellite products in a manner consistent with the dynamics of the Earth system expressed by models. It describes commonalities and potential synergies between assimilation and classical retrievals. This paper explains how the combination of observation operators and their derivatives (linearizations) form powerful research tools. It introduces a technique called automatic differentiation that greatly simplifies both the development and the maintenance of code for the evaluation of derivatives. Throughout this paper, a special focus lies on applications to the carbon cycle.

The role of the Microbial Conveyor Belt on Earth´s system resilience

2021 ◽  
Author(s):  
Mireia Mestre ◽  
Juan Höfer
Keyword(s):  
Human Impacts ◽  
Conveyor Belt ◽  
Earth System ◽  
Planetary Scale ◽  
Microbial Biogeography ◽  
The Earth ◽  
System Resilience ◽  
Global Biogeochemical Cycles

<p>Despite being major players on the global biogeochemical cycles, microorganisms are generally not included in holistic views of Earth’s system. The Microbial Conveyor Belt is a conceptual framework that represents a recurrent and cyclical flux of microorganisms across the globe, connecting distant ecosystems and Earth compartments. This long-range dispersion of microorganisms directly influences the microbial biogeography, the global cycling of inorganic and organic matter, and thus the Earth system’s functioning and long-term resilience. Planetary-scale human impacts disrupting the natural flux of microorganisms pose a major threat to the Microbial Conveyor Belt, thus compromising microbial ecosystem services. Perturbations that modify the natural dispersion of microorganisms are, for example, the modification of the intensity/direction of air fluxes and ocean currents due to climate change, the vanishing of certain dispersion vectors (e.g., species extinction or drying rivers) or the introduction of new ones (e.g., microplastics, wildfires). Transdisciplinary approaches are needed to disentangle the Microbial Conveyor Belt, its major threats and their consequences for Earth´s system resilience.</p>

Trends and projections in ice sheet mass balance

2020 ◽  
Author(s):  
Andrew Shepherd ◽  
Keyword(s):  
Mass Balance ◽  
Sea Level Rise ◽  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Sea Levels ◽  
Global Sea Level

<p>In recent decades, the Antarctic and Greenland Ice Sheets have been major contributors to global sea-level rise and are expected to be so in the future. Although increases in glacier flow and surface melting have been driven by oceanic and atmospheric warming, the degree and trajectory of today’s imbalance remain uncertain. Here we compare and combine 26 individual satellite records of changes in polar ice sheet volume, flow and gravitational potential to produce a reconciled estimate of their mass balance. <strong>Since the early 1990’s, ice losses from Antarctica and Greenland have caused global sea-levels to rise by 18.4 millimetres, on average, and there has been a sixfold increase in the volume of ice loss over time. Of this total, 41 % (7.6 millimetres) originates from Antarctica and 59 % (10.8 millimetres) is from Greenland. In this presentation, we compare our reconciled estimates of Antarctic and Greenland ice sheet mass change to IPCC projection of sea level rise to assess the model skill in predicting changes in ice dynamics and surface mass balance.  </strong>Cumulative ice losses from both ice sheets have been close to the IPCC’s predicted rates for their high-end climate warming scenario, which forecast an additional 170 millimetres of global sea-level rise by 2100 when compared to their central estimate.</p>

scholarly journals Shrinking Ice Sheets Lifted Global Sea Level 14 Millimeters

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Tim Hornyak
Keyword(s):  
Sea Level ◽  
Satellite Data ◽  
Ice Sheets ◽  
Global Sea Level

Researchers measure both grounded and floating ice sheets using satellite data spanning a 16-year period.

scholarly journals Antarctic climate and ice sheet configuration during a peak-warmth Early Pliocene interglacial

2016 ◽  
Author(s):  
Nicholas R. Golledge ◽  
Zoë A. Thomas ◽  
Richard H. Levy ◽  
Edward G. W. Gasson ◽  
Timothy R. Naish ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Co2 Concentration ◽  
Geological Evidence ◽  
Early Pliocene ◽  
Air Temperatures ◽  
Climate Envelope ◽  
Global Sea Level ◽  
Antarctic Ice Sheets

Abstract. The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investigate how Antarctica evolved under orbital and greenhouse gas conditions representative of a peak warmth interglacial in the early Pliocene at 4.23 Ma. Using offline-coupled climate and ice-sheet models, together with palaeoenvironmental proxy data to define a likely climate envelope, we simulate a range of ice-sheet geometries and calculate their likely contribution to sea level. In addition, we use these simulations to investigate the processes by which the West and East Antarctic ice sheets respond to environmental forcings and the timescales over which these behaviours manifest. We conclude that the Antarctic ice sheet contributed approximately 8.5 m to global sea level at this time, under an atmospheric CO2 concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points.

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