Tucked away at the Glencanisp Lodge (Lochinver, Scotland) at the base of the Suilven mountain, the recent PALSEA2 meeting focused on databases of sea-level indicators. The meeting brought together experts from the ‘data’ and ‘modelling’ communities. iGlass was well represented (the meeting was organised by iGlass members Natasha Barlow and Anthony Long) with presentations from André Dϋsterhus, Peter Clark, Roland Gehrels, Fiona Hibbert, Glenn Milne, Matt Whipple and Felicity Williams.
Two field days introduced us to the geology and glacial history of the area, as well as examples of salt marsh and isolation basin records of past sea level change. Two days of presentations brought together the latest work on sea-level change and ice sheet interactions with a focus on sea level database creation and their application. Discussions enabled participants to gain insights into the work of others: for some it was their first close encounter with glacial till or salt marsh records in the field, for others it provided useful primer on U-series and cosmogenic dating, as well as insights into data-model integration/comparison.
The relaxed setting allowed senior and junior scientists to interact within a friendly environment and enjoy the stunning Scottish scenery (posters outside, in Scotland, in September!).
The iGlass consortium was well represented at this years EGU conference in Vienna. Highlights included the co-organised session (CL5.11) “Sea level in interglacials and the last deglaciation” which included the “Milutin Milankovic Medal Lecture” given by Maureen Raymo. It thematised her career with a special focus on her work on the climate variability over the past four million years.
iGlass members gave talks on their current work: Roland Gehrels spoke on the variability of sea-level in the north atlantic during the last millennium; André Düsterhus on the uncertainties of sea-level during the last interglacial and; Fiona Hibbert on a global repository of coral and speleotherm records for past sea level change.
iGlass was also well represented at the poster sessions: Emelie Capron presented a high latitude temperature evaluation across the last interglacial (see current blog), Katy Pol summarised climate in older interglacials (MIS 7,9 and 11); Joy Singarayer presented insights into the modelling of the thermometric contribution to global and regional sea-level rise during the last interglacial; Margot Saher looked at the modes of interglacial sea-level change; Karine Wainer showcased new constraints for MIS 5 and 7 for the Bermuda sea level and; Felicity Williams presented two posters on the use of isostatic scenarios to access coherence between continuous and instantaneous sea level indicators during the last interglacial.
Furthermore, many more contributions of iGlass members were presented in other sessions during the conference week. All in all the conference was seen as a good showcase for our work, which showed the broad range and depth of this project to a wider scientific community!
Research being undertaken by several members of the iGlass community was presented at the recent EGU 2014 conference in Vienna and picked up by the BBC.
With the title “Scientists Probe Earth’s Last Warm phase” the article describes how the most comprehensive data record for the Last interglacial has been compiled and provides new insights into the patterns of warming at the poles during this time. Dr Emilie Capron, an iGlass research scientist at the British Antarctic Survey, told the BBC:
“Interglacial conditions, warm conditions, were in place earlier in the Southern Hemisphere than in the Northern Hemisphere.
Eventually, the Northern Hemisphere catches up and then both poles are warmer than they are today. It’s something we knew looking at a few records, but now we have more records showing exactly the same pattern”
To read more on this story or hear Emilie speaking to the BBC news please go to the following link
The older the sediments, the more macho the equipment. Do you want to core a thousand years of salt marsh sediments? Just bring your hand auger and a gouge. And some muscle power, and a willingness to get really close to the muddy side of science. Do you want to core through interglacial sediments? That might not be so easy. As the name “interglacial” already suggests; these sediments are quite likely to be wedged between glacial sediments. And these may very well consist of gravelly stuff that’s awful to core through. If you need to drill through these to get to the sediments of your choice, bring at least a road drill. The percussive force of the drill will break through all the pesky flints you might encounter below. And a core barrel that’s rammed down with such force won’t be easily pulled out, so a big sturdy jack system is needed to pull the barrel up through the sucking mud and obstructing gravel.
A set-up like that can take you through many metres of unforgiving sediment, but there are limits to it. We know that because we tried it. If the core barrel is stuck, you have to pull the levers of the jack with all the power you can muster, but you might find what that results in is that you push the jack into the ground, rather than pull the barrel up. You might add some solid wooden beams to place under the jack to stop it from sinking into the ground; that will just break them. We tried that too! So there is a moment when you have to upgrade from the road drill. And the next step up is quite a step. The next step up is a drill rig. We had pushed the limits of the road drill set-up in the hunt for our iGlass interglacial sediments. So we had to take the next step. Fortunately, we had expected that, and there was budget for it.
The difference between a road drill and a drill rig is mainly the size. Another difference is that if you rent it, you get people to work it with that. So from struggling through brambles and barbed wire to get to a muddy field where we had to do everything physically possible to not lose the core barrel underground, we were suddenly upgraded to overseers who watch other people get muddy and achy and tired. And these muddy, achy and tired people would give us what we couldn’t possibly get ourselves: wide, intact sediment cores, all the way through the interglacial sediments to whatever lies below. And they delivered!
It was in rural Norfolk we got to meet our drillers. They arrived in a Land Rover with the rig as a trailer behind it. We asked them to set it up at Horse Fen, one of our critical field sites, where we had not been able to core the lower contact of the interglacial sediments. We had to set up at some distance from the old drill holes, in order no not disturb our badger neighbours. So the men erected the quadripod, hammered metres of casing into the ground, and started drilling through the glacial sands on top of our interglacial clays. These we don’t need for our research, so we just chucked these away. That saves time. They drilled down to where we expected the clay to start. And they drilled deeper. And deeper. We started to get worried. By the time we were wondering if they were drilling into an entirely glacial succession we hit the clay. The stratigraphy is very laterally variable in this area! We cored and retrieved the clay, which was a lot thicker than we expected, and finally hit the freshwater peats. And then the rig did what we had hired it for: it drilled through these. We knew we had a beautiful, undisturbed contact in our core liner. What would we find below? That was something we would not know until we got to the lab!
Prof. Tony Payne (Bristol University) contributing author on recent study (Favier et al., 2014. Nature Climate Change doi:10.1038/nclimate2094) showing that Pine Island Glacier’s grounding line is probably engaged in an unstable 40 km retreat. Using ‘state-of-the-art’ ice-sheet modelling, the team demonstrated that the dynamic contribution to sea level rise will remain at a significantly higher level compared with conditions prior to the retreat (equivalent to 3.5–10 mm eustatic sea-level rise over the 20 years).
Following the publication of their recent paper in Scientific Reports, Professor Eelco Rohling was interviewed by Australia’s 9News programme and Dr Ivan Haigh was interviewed by local radio station Wave102. The recent paper looked at modern sea level rise within the context of information from the geological record. They conclude that the present rate is rea level rise is rising rapidly by natural standards. Present sea level rise is currently (just) within natural limits but continued monitoring is needed to determine if and when it goes outside of these limits (and our current understanding) with potentially severe consequences.
You can hear Ivan’s interview here and watch Eelco’s interview
In its most recent report, the Intergovernmental Panel on Climate Change’s predicted sea levels are likely to rise by between 0.26 m and 0.97 m by 2100 – a range encompassing both its highest and lowest emissions scenarios. But according to a new survey of sea level experts, the results of which have been published recently on line in Quaternary Science Reviews, that range might be an underestimate. In the study 90 researchers from 18 different countries were asked for their expert opinion on future sea level rise.Two thirds of those questioned said they thought sea levels could rise higher than the IPCC’s upper estimate for the end of the century.
Over the coming weeks we will introduce members of each team working on the iGlass consortium project. Today we will introduce the team from the National Oceanography Centre in Liverpool.
Dr Mark Tamisiea
Mark Tamisiea is a geophysicist that studies the motion of the Earth’s crust and variations of water depth in the oceans caused by past and present changes of the ice sheets. This collective response of the crust ond oceans is typically called glacial isostatic adjustment (GIA). His Ph.D. in physics from the University of Colorado at Boulder examined how solid-solid phase transitions in the Earth’s mantle might affect observations of GIA. Starting with his post-doc at the University of Toronto, his work has focused on the regional sea level changes caused by GIA. Understanding the regional differences is vital to interpreting the causes of past and present sea level change. Mark has been at the National Oceanography Centre (formally the Proudman Oceanographic Laboratory) since 2007 and prior to that was at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts.
Dr Svetlana Jevrejeva
Svetlana Jevrejeva is a physical oceanographer who works for NOC Liverpool since 2002. Her main research interests are in the variability of global and regional sea level change and development and application of advanced statistical methods. She had contributed to the development of the wavelet coherence method and is author of the unique sea level reconstruction since 1700. She has major publications in the field of time series analysis and the application of novel statistical methods to earth science problems. During the Fifth Assessment report of Intergovernmental Panel of Climate Change (IPCC) she was a Lead Author of the Working Group 1 chapter on Sea level changes. Recent work has focused on sea level projections by 2100, changes in extreme sea levels in the past and their link to climate change.
Dr André Düsterhus
André Düsterhus is a meteorologist specialised in statistical data analysis. He is part of iGlass since 2013 and is working on the connection between GIA modelling and observations of the sea-level variations in the past interglacials. This is done by using verification and data assimilation techniques with a focus on Bayesian statistics. Prior to his appointment at NOC Liverpool, André had received his diploma and PhD in meteorology at the University of Bonn and worked within the climate dynamics workgroup of Andreas Hense. His PhD thesis covered the development of quality assurance procedures within data publication processes. A focus was set therein on the development of statistical quality assurance tests on general data and data peer review schemes.
Metres of sea-level change. Hundreds of thousands of years. The entire globe. The scale of the iGlass research project is rather large. But some of the research is based on the humblest of creatures: benthic foraminifera.
If you have a really big one it might be an entire millimetre. Benthic foraminifera are unicellular protists who live on top of, or in the top layer of, marine sediment. Every species has its own niche; for instance, some like coarse sediments, some like fresh food, some like warm water, etcetera. Some of the more adventurous species even live in salt marshes. These are, if you will, the scuba divers among foraminifera; all foraminifera need salt water to live, but these brave souls have become accustomed to do without for substantial amounts of time.
The reason why foraminifera, in spite of being such modest creatures, get so much attention from the palaeoclimate community is that they build some sort of skeleton, and aretherefore often very well preserved in sediments. They can be tens of millions of years old and still look like they died last week. They take the information they contain into their graves, and in this case that’s a good thing. If you know which species prefers what environment, you can “read” sediments they are found in.
The York and Durham teams drilled cores through interglacial sediments.
We drilled in the middle of Norfolk, but we know that area has been inundated in previous interglacials, and indeed, we found both freshwater and marine sediments in our cores. And using the foraminifera in them, we are reading them. We are looking for changes reflected in the various species encountered; will we get a gradual change from the shallowest foraminifera, which are the ones that actually live above sea level but still within reach of high tide, through the ones that live in shallow water, to those that prefer deeper waters? Or will we see several of such sequences? Or an instantaneous shift from no foraminifera to relatively deep-water species? Watch this space for results…
We found some 10, 000 foraminifera (and counting). They were picked out of the samples by two different scholars, so we keep them all in order to be able to check we have comparable ideas of which species is which (since you ask; no, identifying the species is not a straightforward task). Keeping them also allows us to always go back to the source material in case of questions arising. And after the questions iGlass asks have been answered, who knows what other questions such a collection can help tackle!
Over the coming weeks we will introduce members of each team working on the iGlass consortium project. Today we will introduce the team from the School of Geographical Sciences at the University of Bristol.
Professor Tony Payne
Tony is a Professor of Glaciology in the School of Geographical Sciences and has a BSc in Environmental Science from the University of Stirling and a PhD in Geography from the University of Edinburgh. His PhD focussed on the numerical modelling of former ice sheets. Tony’s work today mainly centres on the development and application of numerical models of glacier and ice sheet flow in order to understand the evolution and dynamics of ice streams, and their effect on the stability of ice sheets. He has a particular interest in modelling the evolution of Pine Island Glacier in West Antarctica.
Tony is a co-director of the Centre for Polar Observation and Modelling (CPOM) and was heavily involved in the recent European project ICE2SEA. Tony is also a lead author of the chapter on sea level change in the very recently published 5th IPCC report.
Dr Dan Lunt
Dan Lunt is a Reader in Climate Science in the School of Geographical Sciences and has an MPhys from the University of Oxford and a PhD on modelling the dust cycle during the Last Glacial Maximum from the University of Reading. His research interests are broad but with a particular focus on climate – ice sheet interactions during the past and in the future. Dan aims to understand the mechanisms affecting past climate change using a model-data synthesis approach . This allows models to test hypotheses derived from interpretation of paleo-data while also providing the data community with information where useful data can be collected to test new hypotheses derived from models.
Dan is an executive editor of the EGU journal, Geoscientific Model Development, which is primarily for model descriptions, from box models to GCMs. The philosophy behind the journal, is to improve rigour and traceability in climate modelling. He is also involved in the iGlass related European Project Past4Future and is a contributing author of the chapter on past climate change in the 5th IPCC report.
Dr Joy Singarayer
Joy Singarayer is an Associate Professor of Palaeoclimatology in the Department of Meteorology at the University of Reading, having recently left the School of Geographical Sciences at the University of Bristol. Her interests are in Quaternary climate change and further back in time with an emphasis on understanding interactions between humans, land cover/use, and climate, prehistoric and present.
Apart from iGlass, Joy has been and is involved on the following projects: terrestrial methane cycling during Paleogene greenhouse climates (NERC), the Palaeoclimate Model Intercomparison Project (PMIP3) – LGM and Holocene terrestrial carbon fluxes and climate, climate change in the last glacial cycle (BBC) and cooling the climate with crops using biogeoengineering (DEFRA).
Dr Emma Stone
Emma Stone is a Research Associate in the School of Geographical Sciences. She has been at Bristol since 2006 where she completed a PhD (supervised by Dan Lunt and Paul Valdes) on the impact of vegetation feedbacks on the evolution of the Greenland ice sheet under future and past climates. Previously Emma undertook an MEarthSci at the University of Bristol and an MSc in Applied Meteorology at the University of Reading. She is particularly interested in understanding climate – ice sheet interactions during past warm periods.
As a researcher for the European Past4Future and iGlass projects, Emma uses climate models of various complexity to model the climate interactions during the Last Interglacial (LIG) period with an emphasis on model-data comparison and is currently working on developing a robust statistical methodology for model-data comparison. The climate output will be used in conjunction with ice sheet modelling to predict sea-level change during the LIG.
Mr Matthew Whipple
Matt Whipple is a PhD student in the Geographical and Earth Science Departments and is supervised by Mark Siddall, Eric Wolff, Joy Singarayer and Dan Lunt. Before starting his PhD in 2011 Matt completed a BSc in Geophysics at the University of Liverpool. His PhD is funded by the iGlass project and is focussed on investigating changes in the Antarctic ice sheet and contributions to sea level during the LIG, and other past warm periods. He uses several methodologies which involve combining output from glacio-isostatic adjustment models, climate models, and ice core isotope records.