1. Greening of retreating glaciers: storage versus export of autochthonous organic matter
2. Automated biogeochemical sensing of icy ecosystems
3. Biogenic production of climatic amplifiers under ice
4. Impact of iceberg sediment release to the Southern Ocean to CO2 drawdown
5. Direct measurement and sampling of Subglacial Lake Ellsworth: a multidisciplinary investigation of life in extreme environments and ice sheet history
6. Cryo-Egg: enabling wireless communications for a deep subglacial application
7. Antarctic ice mass fluxes from satellite observations
8. Understanding contemporary change in the West Antarctic ice sheet
9. National Centre for Earth Observation (NCEO) climate and cryosphere themes
10. Joint Climate Research Programme (JCRP)
12. Estimating and reducing the uncertainty in the future behaviour of the Greenland Ice Sheet
Glaciers are vast reservoirs of biological cells and other debris. Melting of the ice surface promotes increased levels of microbial activity via the creation of unique life-habitats (e.g. cryoconite holes). Colonisation of these niches subsequently leads to further darkening of the ice surface. The result is enhanced absorption of solar radiation, promoting further melt and providing yet more water for microorganisms, which are then dispersed to other parts of the ice surface. This dispersal also transfers the microbes, organic matter and debris to adjacent ecosystems, including the glacier forefields, the glacier bed and shallow marine environments. We hypothesise that glaciers become increasingly biological as they decay, and that glacier wastage is, in part, a biologically-mediated process that initiates ecological succession long before the ice has disappeared.
This project aims to quantify these biological effects on glacier mass wastage by examining the surfaces of retreating Arctic valley glaciers, and to determine fluxes and quality of organic matter (OM) exported to downstream environments. In particular, we aim to determine the importance of positive net primary production (i.e. autochthonously produced organic carbon) in promoting organic matter (OM) accumulation (demonstrated under our previous NERC grant NE/D007321/1), ice surface darkening and OM export downstream. We will also quantify allochthonous carbon deposition and melt out, and consider its interaction with the autochthonous carbon during biological (respiration) and physical (fluvial) processes of removal. In doing so, we aim to produce the first quantification and characterisation of bio-physical effects on ice mass wastage during deglaciation.
Ice-bound ecosystems remain the least explored sector of the cold biosphere, yet are now known to be a viable habitat for extremophile microbial life. They represent the closest earthly analogue for life on other icy planetary bodies, and were potential refugia for life during past global glaciations. In comparison to the deep oceans, for which remotely operated vehicles and specialist instrumentation have been developed, almost no specialized chemical/biosensors exist for use in icy ecosystems. In such physically remote settings, extreme cold, desiccation, high radiation, high pressure and physical abrasion by meltwater/ice are common environmental stresses. As a consequence, most biogeochemical investigations to date have relied on manual sampling of meltwaters, giving a small number of temporally discrete measurements. Such sampling methods yield limited information and are inappropriate for investigating more remote sub-surface environments, such as subglacial lakes. Significant innovation in the field of chemical/biosensor development is essential for temporal/spatial variability in microbial activity in the cryosphere to be understood, and in order to engage fully in the future exploration of Antarctic subglacial lakes and sub-ice water bodies on other planets (e.g. Mars, Jovian moons).
This project aims to develop the first generation of chemical/biosensors for high resolution monitoring of the liquid water component of the cryosphere. This will enable quantum leaps in our understanding of life and life habitats in these extreme cold environments and will contribute to the sensor developmental component for the Lake Ellsworth Programme. The sensor testing site is a glacier, Engabreen (Norway), where environmental stresses common to a range of icy ecosystems are present. A unique aspect of this site is the exploitation of the Svartisen Subglacial Laboratory, which enables relatively straight-forward emplacement of sensors in the high stress sub-surface environment. This work will provide a platform for the future development of a larger research group focused on biogeochemical sensing of the cryosphere and the acquisition of further funding from a variety of sources.
Funder - NERC
Value - £445,342
Dates - October 2007 to October 2010
This project aims to address a significant gap in our understanding of the Earth's global carbon cycle, namely carbon cycling in subglacial habitats. Ice covers between 11 to 18% of the Earth's surface during Quaternary glacial cycles and may have been even more widespread in ancient periods of the Earth's history such as the Neoproterozoic. In contrast to other parts of the Earth's biosphere, cycling of carbon compounds beneath glaciers and ice sheets is poorly understood, since these environments were believed to be devoid of life. Significant populations of microbes (107/ml) have recently been found in subglacial settings. Evidence shows that, as in other aqueous sedimentary environments, subglacial microbes are able to process inorganic and organic carbon forms over a spectrum of redox conditions, producing climatic amplifiers CO2 and CH4. Almost nothing is known about 1) the range of carbon compounds available to subglacial microbes, 2) the degree to which they can be microbially degraded and 3) the rates of degradation and the full spectrum of reaction products. This information is critical to understanding the global carbon cycle on Earth. The fate of some ~330 Pg of organic carbon during the advance of the Quaternary ice sheets over the boreal forest, for example, is unknown and is likely to depend fundamentally on microbial processes in subglacial environments.
Current models of Earth's global carbon cycle assume this carbon is "lost" from the Earth's system. The possibility that it is degraded by subglacial microbes to CO2 and CH4 has not been considered, despite there being potential to explain the millennial to century scale increases in atmospheric methane during Quaternary warm periods. Subglacial environments lacking a modern carbon supply may represent ideal model systems for Snowball Earth and icy life-habitats on other terrestrial planets (e.g. Mars and Jupiter moons, and may be used to propose life viability and biogeochemical processes in these more extreme systems.
Our overall aim is to produce a quantitative estimate of the importance oficebergs in modifying CO2 drawdown in the Southern Ocean. Specifically, we aim to:
a. Predict the spatial and temporal pattern of nutrient release into the Southern Ocean from icebergs, model the biogeochemical response to these inputs, and calculate the contribution to the modern carbon budget related to iceberg iron delivery.
b. Apply the model to the Last Glacial Maximum (LGM) to investigate to what degree changes in iceberg fluxes in this period could explain changes in atmospheric CO2.
c. Provide predictions of the role of icebergs in changing the biological productivity and atmospheric CO2 draw down in the Southern Ocean through sensitivity studies for future climate change scenarios.
We will complete the following five objectives to accomplish these aims:
a. To gather data necessary for input to the model to constrain the rate and location of iceberg discharge from the Antarctic Ice Sheet.
b. To develop an iceberg model to include a versatile sedimentation scheme that can model the spatial and temporal release of bioavailable iron to the surface ocean.
c. To use an ocean-atmosphere model to force the model for 3 times periods; the present day, the LGM and for future climate scenarios to predict the variation in iceberg melt and flow during these periods.
d. To assess the impact of the bioavailable iron sediment release from icebergs on the biogeochemistry of the surface ocean using an Earth System model including a detailed oceanic carbon cycle.
e. To run a dust model within the same Earth System Modelling (ESM) framework and calculate the relative impact of dust fertilisation of the oceans compared to that of icebergs.
The objectives of this work package are to compare the water chemistry of Lake Ellsworth with that of the incoming ice melt to determine the following aspects of the physical, chemical and biological properties of the lake:
a. the residence time of the water and the nature of circulation and stratification
b. the dominant geochemical processes,
c. the nature of biogeochemical reactions and, hence,
d. geochemical indicators of life.
Funder - NERC
Value - £185,000
Dates - TBC
Associated staff - Jemma Wadham (PI), Burrow (Aerospace Engineering), Craddock, Hilton (Electrical Engineering), Drinkwater (Mechanical Engineering) and Kendall (Earth Sciences).
A dramatic shift in wireless systems capability is required over the next 5-10 years to widen data capture to the entire Earth's surface, and hence to reduce uncertainty in forecast modelling under future change scenarios. The basal regions of ice sheets represent just one example of several deep sub-surface environments which currently feature as "voids" in our knowledge of Earth system function since extreme conditions and inaccessibility often prevent the use of cabled sensors. There have been no wireless sensors developed for deep ice sheet environments, where there is a pressing need to improve understanding of future response to climate change and to determine the sustainability and function of life-habitats. This proposal aims to provide the first proof-of-concept evaluation of wireless communications technologies for a deep subglacial application, suitable for incorporation in a future autonomous sensing system ("Cryo-Egg"). A wide range of technology challenges are embodied within this extreme icy environment, making solutions applicable to many less extreme but equally remote sub-surface situations where rock, water and or ice are present (e.g. deep ocean, mines, rock boreholes, permafrost). Technologies developed will have numerous possibilities for future uptake by deep ice sheet drilling science campaigns, to include, the Lake Ellsworth Exploration Programme.
Funder - NERC
Value - £215,723
Dates: March 2007 to August 2010
The Antarctic ice sheet is the largest freshwater store on Earth by an order of magnitude and contains enough ice to increase global sea level by ~65 m. Changes in the input and output of ice (the mass balance) have profound implications for sea level, ocean circulation and inferences concerning the stability of the ice mass. The mass balance of the ice sheet is controlled by both short term and long term processes related to changes in snowfall and ice dynamics. To understand how the ice sheet is behaving now and to be able to predict how it will behave in the future we need to be able to quantify and separate the processes responsible for the trends in mass balance.
Some recent research using satellite measurements of elevation change suggests that increased snowfall may be contributing to a positive mass balance for large sectors of the East Antarctic ice sheet (EAIS). This conclusion, however, is not universally accepted and the results do not account for processes related to ice dynamics close to the margins of the ice sheet. Other recent studies, using different satellite data, suggest that overall, the ice sheet is losing a large amount of mass and that the EAIS is roughly in balance. To solve the open and crucial question of whether the EAIS is losing or gaining mass and to better understand the mass balance trends for the whole ice sheet, we will obtain accurate, regional-scale mass balance measurements with well constrained error budgets.
In this project, in collaboration with US and Dutch partners, we will determine the mass balance of individual drainage basins covering ~85% of the ice sheet and the larger floating ice shelves using a combination of new and existing satellite observations and atmospheric modelling. In particular, we aim to determine conclusively whether the East Antarctic Ice Sheet is a net source or sink of ocean mass. We also aim to investigate the relative importance of trends in snowfall and ice dynamics in the mass budget of the ice sheet.
Funder - NERC
Value - £537,046
Dates - October 2007 to December 2011
Recent satellite observations of the Antarctic ice sheet show dramatic changes over the last decade or so. Two main types of change are seen. The first happens near the coast of the Amundsen Sea and affects several ice streams in the area, such as Pine Island and Thwaites Glaciers. Ice streams are rivers of fast-flowing (up to 1 km/yr) ice that are approximately 40 km wide and several hundred kilometres long, they are separated from the neighbouring slow-flowing (typically 10 m/yr) ice by abrupt shear margins. In these ice streams, the ice appears to be thinning at the rate of several metres per year. The other type of change is found deeper inland on the Siple Coast where one ice stream is thickenning and others show signs of lateral migration. Other evidence (such as buried crevasses) suggest that the flow of the ice streams in this area is very erratic and prone to the occasional shutdown.
Air temperatures are so cold in Antarctica that there is very little surface melt and so changes in ice thickness are most likely caused by changes in the horizontal flow of ice, which can lead to thicker ice if the flow slows, or to thinning ice if it accelerates. Researchers believe that the first of the two observations highlighted above may be caused by warming ocean waters around Antarctica. This leads to increased melt from the underside of floating ice shelves, which therefore thin and tend (through buoyancy) to float more. This, in turn, reduces the amount of friction these ice masses experience as they flow over peaks and troughs in the subglacial topography. The net effect is that the ice shelves and their upstream ice streams accelerate and therefore thin. This type of process has been taken as an indicator of contemporary climate change. Until we know the cause of the oceanic warming (if it indeed exists), we will not be able to attribute this thinning to natural or anthropogenic causes.
The strange behaviour of the ice streams along the Siple Coast is not thought to happen because of changes in the oceans. This is because the coast in this area is protected by the huge Ross ice shelf and water temperatures in the area are extremely cold. The observations of change in this area could be a reflection of the internal variability of ice flow and the analogy to 'weather' is often drawn. Ice streams are thought to be inherently unstable and prone to surges and periods of stagnation, like their smaller counterparts the valley glaciers. This behaviour may be caused by changes in the flow of water under the ice streams, which affects ice-steam flow because it lubricates any sediments at the base of the ice. Changes in water flow can therefore cause an ice stream to experience more friction and to stagnate. Both of the types of change that have been observed are therefore associated with the dynamics of ice streams. In this project, we want to understand this behaviour by constructing a numerical model of the ice sheet which has sufficiently fine resolution to capture the the shapes of individual ice streams and ice shelves. This means that we will need to develop a method of doing calculations on a coarse grid for the whole of the ice sheet and on nested, finer grids for individual ice streams and shelves. In order to capture the behaviour described above, we will also have to develop models of new processes such as the transmission of stresses through an ice mass, the flow of water at its base and the interaction between this water and the softness of the underlying sediments.
We will also have to integrate satellite observations of the ice sheet to produce an accurate model of its present-day flow. Once complete, the model will be used to assess the longer-term effects of changing ocean temperatures on the ice sheet. It will ultimately provide a tool to help us predict what Antarctica's contribution to future global sea level will be.
Funder - NERC
Value - £612,380
Dates - April 2008 to March 2013
Our goal is to use new EO data to quantify changes in the mass balance of the cryosphere and to develop new models to represent the relevant processes in coupled climate prediction models.
Some of the most compelling signs of climate change are found at high latitudes. The coupled evolution of sea-ice and ocean circulation remains a source of great uncertainty for predicting the global effects of climate change. The Arctic, which may become ice free in a matter of decades is a primary focus of the International Polar Year (IPY) and is highlighted in NERC's strategy. Processes involving sea-ice in the region, not only affect local heat budgets, but are also strongly tied to the rest of the climate system via the ocean thermohaline circulation. We will be using data from new EO sources to guide and to integrate the collection of in situ data, new models will be developed to define physical processes that control changes in the cryosphere.
Our priorities include:
a. To use new EO data to provide complete altimetric coverage of polar regions for the first time
b. To determine with unprecedented accuracy the absolute ocean circulation in the Arctic and the mass balance of ice sheets
c. To build on the regional studies that are taking place through IPY and ensure that their legacy is extended into the future
d. To develop rigorously tested models of the processes involving ice in the climate system.
The work in Bristol focuses on developing models of the interactions between floating ice shelves and the ocean.
Website - http://www.nceo.ac.uk/
Funder - NERC
Value - £114,976
Dates - April 2009 to June 2012
The aim of the JCRP is to strengthen links between the NERC research community and the Met Office. The Bristol project is to incorporate a state-of-the-art ice sheet model into the Hadley Centre's suite of climate models, in particular HadCM3 and FAMOUS. The work is tightly integrated to developments being made within the NCEO project.
Funder - European Union Framework 7
Value - €768,507
Dates - March 2009 to February 2013
The melting of continental ice (glaciers, ice caps and ice sheets) is a substantial source of current sea-level rise, and one that is accelerating more rapidly than was predicted even a few years ago. Indeed, the most recent report from Intergovernmental Panel on Climate Change highlighted that the uncertainty in projections of future sea-level rise is dominated by uncertainty concerning continental ice, and that understanding of the key processes that will lead to loss of continental ice must be improved before reliable projections of sea-level rise can be produced.
The ice2sea programme will draw together European and international partners, to reduce these uncertainties. We will undertake targeted studies of key processes in mountain glacier systems and ice caps (e.g. Svalbard), and in ice sheets in both polar regions (Greenland and Antarctica) to improve understanding of how these systems will respond to future climate change. We will improve satellite determinations of continental ice mass, and provide much-needed datasets for testing glacier-response models. Using newly developed ice-sheet/glacier models, we will generate detailed projections of the contribution of continental ice to sea-level rise over the next 200 years, and identify thresholds that commit the planet to long-term sea-level rise.
We will deliver these results in forms accessible to scientists, policy-makers and the general public, which will include clear presentations of the sources of uncertainty. The ice2sea programme will directly inform the ongoing international debate on climate-change mitigation, and European debates surrounding coastal adaptation and sea-defence planning. It will leave a legacy of improved understanding of key cryospheric processes affecting development of the Earth System and the predictive tools for glacier-response modelling, and it will train a new generation of young European researchers who can use those tools for the future benefit of society.
Tony Payne coordinates Ice2Sea's work package 5 which will predict the global contribution of glaciers, ice caps and ice sheets to future sea level the next 200 years.
Jonathan Bamber coordinates Ice2Sea's work package 6 which will integrate results from the whole project.
Bristol also has a substantial input to work package 2 which will provide foundation and validation data for the project.
Website - http://www.ice2sea.eu/index.html
Funder - NERC
Value - £73,000
Dates - October 2008 to September 2011
Sea level rise (SLR) is considered to be one of the most economically and socially important consequences of global warming. The potential contribution of the ice sheets dominates uncertainties in projections of future SLR and the fourth assessment report of the IPCC (AR4) was unable to place an upper bound on the contribution of the ice sheets because of an inadequate understanding of processes controlling their future behaviour. Uncertainties in how the climate will evolve are also important. Depending on the climate model and Greenhouse Gas (GHG) scenario the contribution from changes in the surface mass balance (SMB) of the Greenland Ice Sheet (GrIS) could range between ~0 to 4 mm/yr of SLR by 2150. For reference, the AR4 estimates that the GrIS has been contributing 0.21 mm/yr between 1993-2003. Thus, the increase in mass loss (excluding any change in ice dynamics) from Greenland over the next 150 years could go up by a factor of 20 and potentially be the largest single source of SLR but, as mentioned, the uncertainty in predicting the value is large. Further, it has been suggested that the GrIS could be eliminated by a regional temperature rise of > 4.5 degs C, with a final contribution to global SLR of some 7 m. Most simulations from the AR4 exceed this temperature threshold over Greenland by 2100. What impact climate change will have on the net mass balance of the ice sheet (i.e. on both ice dynamic and surface melt effects) and what the likely contribution will be to SLR and freshwater production remain poorly constrained.
The aim of this project is to tackle several key components responsible for this uncertainty relating to how the ice sheet will respond to changing climate and what the uncertainties in the future climate are due to parameter uncertainty in the models used. In addition we will incorporate our results and the SMB model into the next generation of Hadley Centre AOGCMs.