Ocean-ice Interaction in the Ross Sea during Past Warm Periods
Lead Research Organisation:
Imperial College London
Department Name: Earth Science and Engineering
Abstract
The two polar ice sheets in Greenland and Antarctica contain enough ice to raise global sea levels by ~65 metre. In total, 58 metre of sea level equivalent ice is tied up in Antarctica, of which ~4m is located in West Antarctic areas that are particularly vulnerable to environmental change. These are areas where the ice rests on a bed several hundred meters below sea level, meaning the ice is in direct contact with the warming ocean. In such a set up the ice sheet is not just melting from the top down by means of higher atmospheric temperatures and surface melting, but also from the bottom up, via contact with warmer ocean water.
Recent estimates on how fast West Antarctica may lose most of its ocean terminating ice range from a few hundred to a few thousand years into the future. The lower end of this range is just a few generations away, and is something that becomes increasingly likely under unabated carbon dioxide emissions, increased atmospheric carbon dioxide concentrations and resulting global warming.
We can make detailed observations on how the ice sheet reacts to ongoing environmental change. But what we can't observe with our own eyes is what will happen to the ice when global temperature are 1, 2, 4 or even 8 degrees warmer than today.
As Earth Scientists we love our detective stories. Figuring out the response of the Antarctic ice sheets to warmer climates is something we can do by using the mud deposited at the bottom of the ocean. Just like an old-fashioned tape recorder, this mud preserves an environmental signal from times in the past, where earth's climate was warmer and atmospheric carbon dioxide levels were higher than today.
It is such records that we want to recover when we set sail on Expedition 374 of the International Ocean Discovery Program in January 2018 to March 2018. My role on the expedition will be to look at the chemical fingerprint in the mud. Every rock that gets crushed by the overlying ice sheet and transported from the continent to the ocean has a typical fingerprint, just like every human being has a very specific DNA. We can use this fingerprint to decipher where the material was located on the continent, which in turn can tell us about the location of the ice margin that scrapes off the mud. You can imagine that back in times of greater warmth that location was not the same as it is today.
Another part of the climate system that changes with changing environmental conditions is how the oceans circulate and transport heat and carbon around the globe. We are all used to thinking about the Gulf Stream that brings warm waters to the shores of Northern Europe. Down south, next to the giant Antarctic continent, another process comes into play: Freezing of surface waters and interaction of warmer water with cold floating ice shelves creates very salty, cold and dense water, which sinks to the bottom of the ocean. Such waters are called Antarctic Bottom Waters and fill up 30-40% of our global oceans. Will this be the same in a warming world? Or will the retreat of the Antarctic ice sheets also have a major impact on global ocean circulation? Another question we can tackle as Earth Science detectives by looking at the chemical fingerprint of mud.
IODP Expedition 374 is going to be a great opportunity to collect unique material and advance our basic understanding of polar ice sheets and ocean circulation in a warmer world -a world which may just look like the one we are headed towards.
Recent estimates on how fast West Antarctica may lose most of its ocean terminating ice range from a few hundred to a few thousand years into the future. The lower end of this range is just a few generations away, and is something that becomes increasingly likely under unabated carbon dioxide emissions, increased atmospheric carbon dioxide concentrations and resulting global warming.
We can make detailed observations on how the ice sheet reacts to ongoing environmental change. But what we can't observe with our own eyes is what will happen to the ice when global temperature are 1, 2, 4 or even 8 degrees warmer than today.
As Earth Scientists we love our detective stories. Figuring out the response of the Antarctic ice sheets to warmer climates is something we can do by using the mud deposited at the bottom of the ocean. Just like an old-fashioned tape recorder, this mud preserves an environmental signal from times in the past, where earth's climate was warmer and atmospheric carbon dioxide levels were higher than today.
It is such records that we want to recover when we set sail on Expedition 374 of the International Ocean Discovery Program in January 2018 to March 2018. My role on the expedition will be to look at the chemical fingerprint in the mud. Every rock that gets crushed by the overlying ice sheet and transported from the continent to the ocean has a typical fingerprint, just like every human being has a very specific DNA. We can use this fingerprint to decipher where the material was located on the continent, which in turn can tell us about the location of the ice margin that scrapes off the mud. You can imagine that back in times of greater warmth that location was not the same as it is today.
Another part of the climate system that changes with changing environmental conditions is how the oceans circulate and transport heat and carbon around the globe. We are all used to thinking about the Gulf Stream that brings warm waters to the shores of Northern Europe. Down south, next to the giant Antarctic continent, another process comes into play: Freezing of surface waters and interaction of warmer water with cold floating ice shelves creates very salty, cold and dense water, which sinks to the bottom of the ocean. Such waters are called Antarctic Bottom Waters and fill up 30-40% of our global oceans. Will this be the same in a warming world? Or will the retreat of the Antarctic ice sheets also have a major impact on global ocean circulation? Another question we can tackle as Earth Science detectives by looking at the chemical fingerprint of mud.
IODP Expedition 374 is going to be a great opportunity to collect unique material and advance our basic understanding of polar ice sheets and ocean circulation in a warmer world -a world which may just look like the one we are headed towards.
Planned Impact
Monitoring ice sheets and sea level change has risen to the top of the agenda, not only for research institutions, but also for government and policy agencies. The last fifteen years have seen a dramatic increase in observational data, and associated scientific understanding. In the negotiations around the 2015 Paris Agreement, potential sea level rise from future warming and ice melting played a central role in deciding to aim for 'global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius.'
Palaeoclimate research is our only window to investigated ice sheet behaviour under warmer conditions before experiencing them ourselves. Hence society as a hole will benefit from research advancing our understanding on mechanisms of ice destabilisation, tresholds of ice sheet collapse, and associated timescales. The UNFCC commissioned a Special Report on the Impacts of 1.5 degree warming from the IPCC, to be released in early October 2018. Continued basic research needs to inform the questions raised in this report, as any future assessment can only be as accurate as our modern and past observational data are.
Besides policy makers, schools and universities are targeted with outreach activities from aboard the JOIDES resolution. I will help deliver live broadcasts and blogs. Upon return to shore I will give talks at universities, museums and festivals to convey the importance of warming-related ice melting and subsequent sea level rise to the general public and the next generation of scientists. I will also involve a number of graduate and undergraduate students in my post-cruise research.
Palaeoclimate research is our only window to investigated ice sheet behaviour under warmer conditions before experiencing them ourselves. Hence society as a hole will benefit from research advancing our understanding on mechanisms of ice destabilisation, tresholds of ice sheet collapse, and associated timescales. The UNFCC commissioned a Special Report on the Impacts of 1.5 degree warming from the IPCC, to be released in early October 2018. Continued basic research needs to inform the questions raised in this report, as any future assessment can only be as accurate as our modern and past observational data are.
Besides policy makers, schools and universities are targeted with outreach activities from aboard the JOIDES resolution. I will help deliver live broadcasts and blogs. Upon return to shore I will give talks at universities, museums and festivals to convey the importance of warming-related ice melting and subsequent sea level rise to the general public and the next generation of scientists. I will also involve a number of graduate and undergraduate students in my post-cruise research.
Publications
Arndt J
(2018)
Bathymetric controls on calving processes at Pine Island Glacier
in The Cryosphere
Bertram R
(2018)
Pliocene deglacial event timelines and the biogeochemical response offshore Wilkes Subglacial Basin, East Antarctica
in Earth and Planetary Science Letters
Chase Z
(2018)
Discovering the Ocean's Past through Geochemistry
in Elements
Colleoni F
(2022)
Antarctic Climate Evolution
Dziadek R
(2019)
Elevated geothermal surface heat flow in the Amundsen Sea Embayment, West Antarctica
in Earth and Planetary Science Letters
Evangelinos D
(2022)
Absence of a strong, deep-reaching Antarctic Circumpolar Current zonal flow across the Tasmanian gateway during the Oligocene to early Miocene
in Global and Planetary Change
Evangelinos D
(2024)
Late Miocene onset of the modern Antarctic Circumpolar Current
in Nature Geoscience
Gales JA
(2023)
Climate-controlled submarine landslides on the Antarctic continental margin.
in Nature communications
Iizuka M
(2023)
Multiple episodes of ice loss from the Wilkes Subglacial Basin during the Last Interglacial
in Nature Communications
Levy R
(2022)
Antarctic Climate Evolution
Title | Grantham art prize |
Description | Melanie King created spinach anthotype of the B46 iceberg that calved off Pine Island Glacier in West Antarctica. |
Type Of Art | Artwork |
Year Produced | 2019 |
Impact | Great interactions with the general audience at the award ceremony and following reception. |
URL | https://www.melaniek.co.uk/pine-island-glacier#! |
Description | International Ocean Discovery Program Expedition 374 sailed in January to March 2018 to the Ross Sea to collect sediment cores that capture the history of the West Antarctic ice sheet (WAIS). The WAIS is a marine-based ice sheet, which is currently looking mass. In order to better constrain models that simulate its future behaviour, a better understanding on its past reaction to enhanced warming is needed. Five sites were drilled along a latitudinal and depth transect from the shelf to the outer rise and recovered a total of 1292.70 m of high-quality core, spanning ages from ~19 million years ago until recent. Site U1521, which is the focus for this grant, allows unprecedented insight into environmental change on the Antarctic continental shelf during the late early and middle Miocene. A first manuscript has been submitted in January 2021. |
Exploitation Route | We anticipate a number of high profile publications and further impetus for future drilling in the area to resolve the question how the West Antarctic ice sheet reacted to near future temperatures. Our initial results for the Miocene ice sheet dynamics look spectacular and provide a unique insight into solid earth - ocean - ice interactions in the early to middle Miocene. |
Sectors | Education,Environment,Government, Democracy and Justice |
URL | http://publications.iodp.org/preliminary_report/374/374PR.PDF |
Description | GEO ICE - Benchmark Geological Records for the Response of the West Antarctic Ice Sheet to Near Future Temperature |
Amount | £650,191 (GBP) |
Funding ID | NE/W000172/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 07/2022 |
End | 12/2025 |
Description | Sensitivity of the West Antarctic Ice Sheet to 2 Degrees Celsius (SWAIS 2C) |
Amount | $1,200,000 (USD) |
Organisation | International Continental Scientific Drilling Program |
Sector | Charity/Non Profit |
Start |
Title | Neodymium and Strontium isotope compositions of Miocene to recent sediments collected at Site U1521 during International Ocean Discovery Programme (IODP) Expedition 374 to the Ross Sea, Antarctica |
Description | This dataset comprises neodymium (Nd) and strontium (Sr) isotope compositions measured on 72 sediment samples, from IODP Expedition 374 Site U1521 to the Ross Sea. These were collected on the RV JOIDES Resolution. Shipboard biostratigraphy and magnetostratigraphy suggests the samples are mainly early Miocene in age (McKay et al., 2019). The uppermost samples do, however, include younger Plio-Pleistocene sediments. Neodymium and Sr isotope analyses were conducted using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) and a thermal ionisation mass spectrometer (TIMS), respectively, in the MAGIC laboratories at Imperial College London. Neodymium and Sr isotopes in sediments can be compared to measurements from terrestrial rock samples, allowing the changing provenance of the sediments to be traced. This dataset therefore provides information on how erosion by Antarctica's ice sheets bordering the Ross Sea has changed over time. Neodymium isotopes are reported in the epsilon notation, which denotes the deviation in parts per 10,000 from the present-day composition of the Chondritic Uniform Reservoir (143Nd/144Nd = 0.512638) (Jacobsen and Wasserburg, 1980). |
Type Of Material | Database/Collection of data |
Year Produced | 2021 |
Provided To Others? | Yes |
Impact | https://www.nature.com/articles/s41586-021-04148-0 |
URL | https://www2.bgs.ac.uk/nationalgeosciencedatacentre/citedData/catalogue/3a646c8a-8422-4079-a928-a159... |
Title | Zircon U-Pb Sediment provenance data for Miocene to recent sediments collected at Site U1521 during International Ocean Discovery Programme (IODP) Expedition 374 to the Ross Sea, Antarctica |
Description | This dataset comprises zircon U-Pb data on 11 samples, each containing ~90-150 individual grains. This method was applied to sediment samples from IODP Expedition 374 Site U1521 to the Ross Sea, collected on the RV JOIDES Resolution. Shipboard biostratigraphy and magnetostratigraphy suggests the samples are mainly early Miocene in age (McKay et al., 2019). The uppermost samples do, however, include younger Plio-Pleistocene sediments. Samples were measured using an Agilent 7900 laser ablation inductively-coupled plasma mass spectrometer (LA-ICP-MS) with a 25-35 µm pit diameter in the London Geochronology Centre at University College London. |
Type Of Material | Database/Collection of data |
Year Produced | 2021 |
Provided To Others? | Yes |
Impact | https://www.nature.com/articles/s41586-021-04148-0 |
URL | https://www2.bgs.ac.uk/nationalgeosciencedatacentre/citedData/catalogue/cfadf931-0804-484c-a9d0-9625... |
Description | Detrital grain thermochronology, L-DEO |
Organisation | Columbia University |
Department | Earth and Environmental Sciences |
Country | United States |
Sector | Academic/University |
PI Contribution | Geochemical provenance analyses for reconstructing past ice sheet behaviour works best if a multi-proxy approach is taken. Imperial College contributed fine-grained radiogenic isotope analyses to this project. |
Collaborator Contribution | Geochemical provenance analyses for reconstructing past ice sheet behaviour works best if a multi-proxy approach is taken. Columbia University contributed single grain Ar-Ar dates to this project at a greatly reduced cost. |
Impact | This is a long-standing collaboration going back to my own time as research fellow and research scientist at Columbia University. The results to date are ~20 publications in the peer-reviewed literature. |
Start Year | 2010 |
Description | Detrital grain thermochronology, UCL/Birkbeck |
Organisation | University College London |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | U-Pb dating of zircon grains for reconstructing past ice sheet behaviour works best if a multi-proxy approach is taken. Imperial College contributed fine-grained radiogenic isotope analyses to this project. |
Collaborator Contribution | Geochemical provenance analyses for reconstructing past ice sheet behaviour works best if a multi-proxy approach is taken. The London Geochronology Centre at UCL contributed U-Pb zircon dates to this project at a greatly reduced cost. |
Impact | This is the beginning of a broader collaboration on using U-Pb dating in zircon grains in circum-Antarctic sediments to reconstruct the history of Antarctic ice sheets. |
Start Year | 2019 |
Description | SWAIS 2C consortium |
Organisation | GNS Science |
Country | New Zealand |
Sector | Public |
PI Contribution | PI on successful ICDP proposal to set up an international partnership between >10 countries to drill critical climate records from West Antarctica |
Collaborator Contribution | ICDP proposal writing and successful lobbying in 9 other countries to financially contribute to the SWAIS 2C programme. |
Impact | Forthcoming - project officially kicks off in Autumn 2023. |
Start Year | 2019 |
Description | Great Exhibition Road Festival |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Penguin mask workshop - >50 people attended this family and kids events to engage with Antarctic exploration and science by making Penguin masks |
Year(s) Of Engagement Activity | 2022 |
URL | https://www.greatexhibitionroadfestival.co.uk/event/penguin-mask-workshop/ |
Description | Great Exhibition Road Festival - Blast from the Past |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | The Great Exhibition Road Festival is a new three day celebration of curiosity, discovery and exploration that brings together science and the arts in the spirit of the Great Exhibition of 1851.We had a stand to bring the science done by the International Ocean Discovery Programme (IODP) closer to a general audience. From climate change, over earthquakes, to impacts that killed the dinosaurs. We had truly fantastic interactions with countless member of the public, young and old, scientifically-inclined and intrigued. The festival was visited by 60,000 people and our stand was on the main road. |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.imperial.ac.uk/news/193776/great-exhibition-road-festival-2019-earns/ |
Description | Great Exhibition Road Festival - Uncovering our future in Antarctica's past |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | Sparked questions and discussion afterwards. |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.greatexhibitionroadfestival.co.uk/event/uncovering-our-future-antarcticas-past/?backto=w... |
Description | History of Antarctic drilling video |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Participated in filming for a video on the history of Antarctic drilling. |
Year(s) Of Engagement Activity | 2018 |
URL | https://www.youtube.com/watch?v=GN9faSiGUZQ |
Description | Inaugural lecture |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Other audiences |
Results and Impact | Inaugural lecture to a broad audience of colleagues, friends, and the general public. |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.imperial.ac.uk/events/96929/drilling-for-our-future-in-antarcticas-past/ |
Description | MAGIC Elements |
Form Of Engagement Activity | Participation in an open day or visit at my research institution |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Hundreds of under-12s visited the Imperial Festival stand on MAGIC Elements with their parents. They dressed up as scientists, learned about elements and isotopes, and even about how Antarctica once was a continent with palm trees at its shorelines. |
Year(s) Of Engagement Activity | 2018 |
URL | https://www.imperial.ac.uk/news/185986/imperial-festival-transforms-under-12s-into-mini/ |
Description | Media contact Grantham |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Part of a small group of Grantham affiliates that helps with media requests. My expertise is in the are of palaeoclimate and Antarctic ice sheets |
Year(s) Of Engagement Activity | 2016,2017,2018,2019 |
Description | PROCEED workshop |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Study participants or study members |
Results and Impact | >50 international scientist attended the PROCEED workshop (Expanding Frontiers of Scientific Drilling) in Vienna. I co-led the workshop discussion on expanding IODP science in the context of the IPCC. |
Year(s) Of Engagement Activity | 2019 |
Description | Pint of Science 2018 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Outreach talk in a pub to explain science to the general public in a friendly environment. |
Year(s) Of Engagement Activity | 2018 |
URL | https://pintofscience.co.uk/event/understanding-antarctica |
Description | Royal Meterological Society meeting - the Pliocene |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Stimulating meeting to highlight the relevance of the Pliocene climate to our own future. Well attended. Sparked questions and discussion. |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.rmets.org/event/pliocene-last-time-earth-had-400-ppm-atmospheric-co2 |
Description | Royal Meterological Society meeting - the Pliocene |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Media briefing ahead of the Pliocene meeting organised by the Royal Meterological Society and the Grantham Institute for Climate and the Environment and hosted by the Science Media Centre. |
Year(s) Of Engagement Activity | 2019 |
Description | Sutton Summer School 2022 |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | Engagement talk about Earth Science, university, and Antarctica. |
Year(s) Of Engagement Activity | 2022 |
URL | https://summerschools.suttontrust.com/ |
Description | Talk for year 4 in Judith Kerr primary school |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Schools |
Results and Impact | I talked to school pupils who had discussed Antarctic discovery as part of their curriculum about my experiences on research expeditions to Antarctica. I probably have never answer more questions in one hour than from these enthusiastic 7-year olds. |
Year(s) Of Engagement Activity | 2019 |
Description | |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Tweets about climate change, Antarctica, women in science, STEM related topics and (Earth) Science in general. |
Year(s) Of Engagement Activity | 2014,2015,2016,2017,2018,2019,2020 |
Description | Year 9 girls summer school |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | Webinar to enthuse year 9 girls for engineering - sparked questions and discussions |
Year(s) Of Engagement Activity | 2021 |