BAS Chemistry and past Climate
Lead Research Organisation:
British Antarctic Survey
Department Name: UNLISTED
Abstract
Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
Organisations
Publications
Abbatt J
(2012)
Halogen activation via interactions with environmental ice and snow in the polar lower troposphere and other regions
in Atmospheric Chemistry and Physics
Abram N
(2011)
Environmental signals in a highly resolved ice core from James Ross Island, Antarctica
in Journal of Geophysical Research
Abram N
(2014)
Evolution of the Southern Annular Mode during the past millennium
in Nature Climate Change
Abram N
(2013)
A review of sea ice proxy information from polar ice cores
in Quaternary Science Reviews
Abram N
(2013)
Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century
in Nature Geoscience
Abram N
(2010)
Ice core evidence for a 20th century decline of sea ice in the Bellingshausen Sea, Antarctica
in Journal of Geophysical Research: Atmospheres
Abram N
(2009)
Oscillations in the southern extent of the Indo-Pacific Warm Pool during the mid-Holocene
in Quaternary Science Reviews
Abram, N.
(2013)
Sharp rise in summer melt on Antarctic Peninsula
in Planet Earth
Allen C
(2011)
Last glacial-interglacial sea-ice cover in the SW Atlantic and its potential role in global deglaciation
in Quaternary Science Reviews
Allen C
(2014)
Proxy development: a new facet of morphological diversity in the marine diatom <i>Eucampia antarctica</i> (Castracane) Mangin
in Journal of Micropalaeontology
| Description | Between 2009-2015, the BAS Chemistry and Past Climate program has published more than 200 peer-reviewed scientific papers (including Nature and Nature Geoscience). Our key findings include: Rapid warming over the past 50 years on the Antarctic Peninsula is associated with the collapse of a number of ice shelves and accelerating glacier mass loss. We have demonstrated, for the first time that levels of ice melt on the Antarctic Peninsula have been particularly sensitive to increasing temperature during the 20th Century and that continued warming to temperatures that now exceed the stable conditions of most of the last 10,000 years is likely to cause ice-shelf instability to propagate southward along the Antarctic Peninsula. A UK-French science team (led by Dr Robert Mulvaney) drilled a 364-metre long ice core from James Ross Island, near the northern tip of the Antarctic Peninsula, to measure past temperatures in the area. This part of the Antarctic Peninsula experienced an extended warm period, followed by stable temperatures from 9,200 to 2,500 years ago that were similar to modern-day levels. By combining evidence with nearby lake and marine sediment records, which provide ages for deglaciation and biological responses to climate change, we established a connection between past temperature and ice-shelf stability. We also demonstrated that development of ice shelves near James Ross Island was coincident with pronounced cooling from 2,500 to 600 years ago and showed that warming for several centuries after this rendered ice shelves on the northeastern Antarctic Peninsula vulnerable to collapse. Using measurements of the thickness of ice-melt layers in the James Ross Island ice core as a proxy for summer temperature, we showed that almost ten times as much of the annual snowfall is melting each year as it was 1000 years ago. Precise data on the past relationship between land-ice melting and sea level rise are required to improve the numerical models that predict future sea levels. We have derived geological constraints from lake sediments on past changes in relative sea level which provide data for correcting satellite gravity derived measurements of contemporary ice mass loss from some of fastest warming regions across the Antarctic Peninsula. This will improve predictions of the contribution that ice from the Antarctic Peninsula will make to rising sea levels between now and the end of the century. Reconstructing the past extent of the Antarctic Ice Sheet and examining evidence for its deglacial history provides important field data to constrain models of ice sheet change, evaluate the past response of the ice sheet to changes in atmospheric and oceanographic temperature and aid predictions of future sea level change. In 2012, a team from the British Antarctic Survey and the Laboratoire de Glaciologie et Géophysique de l'Environnement, Grenoble, drilled another 654-metre ice core on the Fletcher Promontory in West Antarctica. This ice core contains the remnants of snowfall that fell over the last 130,000 years, indicating that the ice cap in this region did not collapse or disappear during the last Interglacial period when the climate was warmer than today, and that the ice sheet at this time was not substantially lower than present day. A related study, combining ice core data and modelling, suggested that Antarctica may have been as much as as 6oC warmer than previously thought during past Interglacials. Together with national and international colleagues, BAS researchers led parts of a community effort to develop a state of the art synthesis of Antarctic Ice Sheet history for the Last Glacial Maximum and to create a series of time-sliced ice sheet reconstructions for the last 25,000 years. By measuring which species of diatoms were present in marine sediments, we determined the maximum extent of sea ice in the Scotia Sea occurred between 25,000-23,500 years ago, earlier than what is traditionally considered to be the maximum extent of the last Glacial period. The seasonal expansion and contraction of sea-ice during the Last Glacial Maximum would have been approximately double that of modern times. This is likely to have increased the export of Antarctic Bottom Water, which accelerated global thermally-driven oceanic circulation and contributed to events that led to the end of the last ice age. Comparison with records of changing carbon dioxide (CO2) concentrations suggests that the extent of sea ice in the Scotia Sea was not a major cause of CO2 change between 35,000 and 15,000 years ago. Coupled to this, we have shown that natural swings in methane concentration, as observed between the Last Glacial Maximum and the pre-industrial era, cannot have been caused by a reduction in the rate of atmospheric removal. By studying how the atmospheric sink would respond to different aspects of the climate change, we found that different effects almost cancel out. This implies that the rise in methane concentration must have been almost entirely driven by an increase in methane emissions. The methanesulphonic acid (MSA) content of three ice core records from the Antarctic Peninsula has shown that the satellite-observed sea ice decline in the Bellingshausen Sea during recent decades is part of a long- term regional trend that has seen southward retreat of sea ice in this region during the 20th Century. Modern atmospheric chemistry studies have provided evidence that sea ice surfaces, both on the ground and lofted in the air, act as sources of bromine compounds to the atmosphere which can rapidly deplete ozone as well as convert mercury compounds into bioavailable forms. These ozone-depleted air masses can extend over 1000 km, and we demonstrated the link between storm systems, containing saline blowing snow, and elevated levels of bromine, and that such systems may have the wider regional impact. In contrast, on the Antarctic Plateau where ice cores are drilled, the chemical system is controlled purely by the snowpack and the local-regional meteorology. We demonstrated that wintertime studies in Antarctica can be used for "lab-in-the-field" studies of air-snow exchange; sunlight is absent, so exchange is limited to physical processes alone. |
| Exploitation Route | Academics in other areas of palaeoclimate, climate modelling etc. Sea level experts interested in how climate change in the Antarctic is likely to affect future ice loss. The public who are interested in past Antarctic climate and ice core research. |
| Sectors | Education Environment Government Democracy and Justice |
| Description | Our outreach activities have explained how studies of polar ice cores, combined with data from marine and lake sediment cores can be used to understand how unique the recent measured changes in the climate and atmosphere gas composition (particularly greenhouse gases) are compared with the last 10- 800, 000 years. We have also demonstrated that changes in local climate in regions within British Antarctic Territory, and the contiguous ice sheet, could have an impact on rising sea levels over the coming century. Our briefings have included policy makers: Government Ministers (BIS and FCO) and several MPs; the government Chief Scientist; senior Civil Servants from FCO, BOS, DECC, and the MOD; foreign Ambassadors and Civil Servants and our work was discussed at the UN Framework Convention on Climate Change (Copenhagen). Climate change talks, and tours of the ice core laboratory facilities, have been extended to many senior business leaders from industry, particularly the insurance, energy, automotive and retail sectors, plus independent research organisations with climate change interests. The IPCC took advantage of our expertise for their Fifth Assessment Report (Contributing Authorship) and we have led and contributed to steering committees and expert groups in the Scientific Committee for Antarctic Research (SCAR) and in the International Geosphere Biosphere Programme (IGBP PAGES). The re-establishment of atmospheric chemistry work in the CASLab at Halley after the rebuild of the station has been a further achievement that will allow many UK scientists to access this key location for atmospheric research. The station contributed data to the World Meteorological Organisation programme, Global Atmospheric Watch (GAW), and is designed to observe long-term changes in atmospheric composition. Measurement stations from around the globe contribute to this network of observations; many small observatories measure only one or two atmospheric components, but a core, 29 worldwide, have committed to a much more extensive measurement programme - these are referred to as the GAW 'Global' observatories. In May 2013, Halley station was awarded GAW Global status - only the second UK observatory to achieve this accolade. This status was awarded because of the on-going commitment to measurements of reactive trace gases, greenhouse gases, and total ozone. GAW data are submitted to publicly-accessible databases, from where they will be used to derive annual assessments of the "health" of the atmosphere, and to test global numerical models of the atmosphere. |
| First Year Of Impact | 2009 |
| Sector | Education,Environment,Government, Democracy and Justice |
| Impact Types | Cultural |
| Description | Briefings on climate change and greenhouse gases |
| Geographic Reach | Multiple continents/international |
| Policy Influence Type | Contribution to a national consultation/review |
| Description | Communicating climate change advice to policymakers |
| Geographic Reach | National |
| Policy Influence Type | Influenced training of practitioners or researchers |
| Description | The re-establishment of atmospheric chemistry work in the CASLab at Halley after the rebuild of the station and award of GAW Global status |
| Geographic Reach | Multiple continents/international |
| Policy Influence Type | Participation in a guidance/advisory committee |