EXECUTIVE SUMMARY

  It is well-known that the Earth's climate system is defined by complex interactions between oceans, atmosphere, land and ice sheets, and the mechanisms involved in potential future climate changes can be revealed by studying the past. The UK currently supports world-class research in palaeoceanography—the quantitative study of ocean history—investigating ocean and climate interactions at a range of scales throughout the global ocean. In this evidence we highlight the importance of ensuring continued UK sponsorship for the International Marine Past Global Change Study and the critical need for structural and substantive support in this fundamental area of climate change research.

SUBMISSION

  1.  The UK hosts a very active and vibrant research community who study records of ocean change on timescales of decades to millennia and the evolution of past climates. This "palaeoceanographic" community seeks support for its participation in the International Marine Past Global Change Study (IMAGES), for research on past ocean and climate interactions.

  2.  Research on climatic variations during the last few glacial-interglacial cycles has provided many fundamental insights into the rapidity, magnitude and processes leading to past climate perturbations. It is well understood that the Earth's climate system is defined by complex interactions between oceans, atmosphere, land and ice sheets. Due to their massive heat capacity, the oceans provide a "long term memory" for the climate system, but recent advances in ocean and climate research have shown that the ocean Meridional Overturning Circulation (MOC), and with it the warm currents that sustain our temperate climate, can be highly variable with direct implications for the stability of global climate. Records from marine sediment and polar ice cores are of particular importance in documenting the dynamics of the MOC, its sensitivity to variable forcing, and its consequences for climate on regional to hemisphere-wide scales. These palaeo-archives provide compelling evidence for sustained periods, within the last 10s of thousands of years, of dramatic climate oscillations involving many sudden (within a decade) and substantial (up to 15 degrees C) shifts in the global climate system. Insights such as this, obtained from palaeo-studies, have played a crucial role in the development of current NERC flagship thematic programmes (i) Rapid climate change (RAPID) and (ii) Quantifying and Understanding the Earth System (QUEST).

  3.  It is clear that detailed studies of past climate variability are essential to inform us about magnitudes, rates, and sensitivities of the variability inherent to the climate system, and of the processes driving that variability. Modern monitoring and modelling studies, which aim to assess potential future climate change, cannot deliver without the context of a sound understanding of past natural climate variability. Deep-time studies of, for example, ice-free greenhouse climate states in the distant past can be performed only through the Integrated Ocean Drilling Program (IODP). The increases in both temporal and spatial resolution required to resolve processes of abrupt climate change during the last few glacial-interglacial cycles can most effectively be achieved through international marine science consortia such as IMAGES.

  4.  The international structure of IMAGES ensures optimum access to international facilities for all participant nations. A key example is access to ship-time on vessels from the various participant nations best equipped for taking long high-volume sediment cores, which is a major benefit for the UK in the current transition period to its new research fleet. This transition period has led to significant cancellations of sea-going expeditions on the UK vessels and there is a long backlog of awarded sea-going programs to be dealt with. Hence, strategic participation in international consortia offers an important means to ensure progress in the UK natural research agenda. IMAGES has made particularly good use of the French research vessel Marion Dufresne, which has a high-volume giant coring capacity that is unique in the world.

  5.  The international IMAGES programme was established in 1995, with strong input from the UK, in order to respond to the challenge of understanding the mechanisms and consequences of climatic changes using oceanic sedimentary records. IMAGES forms the marine sediment research component of Past Global Changes—International Geosphere Biosphere Program (PAGES-IGBP), and is also supported by the International Council for Sciences, Scientific Committee on Oceanic Research (SCOR). As a founder member of IMAGES, the UK continues to participate actively in the full range of its activities. This includes the incumbent IMAGES Executive Committee chair (Prof E J Rohling, NOCS).

  6.  The major goal of IMAGES is to foster international co-ordination of collaborative scientific programmes aimed at collection and interpretation of high quality palaeoclimate data from the global ocean. It aims to understand the role of marine processes in the Earth's climate system during the past million years at timescales relevant to human life and societal development.

  7.  IMAGES priority scientific objectives are currently:

—  To describe and understand the role of ocean circulation in past climate changes.

—  To describe and understand the role of marine biogeochemical cycles in past climate changes.

—  To describe and understand the impact of past ocean changes on continental environments and the development of human civilization.

—  To develop novel methods to better quantify the key processes that define the role of the oceans in past climate changes.

  8.  To further these aims, IMAGES organises sea-going sampling missions, thematic and regional working groups, workshops and conferences. The focal point of IMAGES activities is formed by working groups (WG). Organised around specific scientific questions or themes, working groups allow an international consortium of scientists to focus questions and ideas, develop a plan, and marshal the required operational resources, thus working together towards a successful, internationally supported, strategy to address the topic.

  9.  Original IMAGES priorities for coring expeditions primarily concerned areas of high biological productivity, hydrographic frontal regions, ocean margins, and areas of active deep-water transport and their associated sediment drifts. Project development by the WGs has enabled IMAGES to systematically visit many of the original target areas while maintaining a flexible approach for response to emerging challenges. Examples of successful past WGs include those that led to coring expeditions involving or led by UK scientists, such as the WEPAMA effort to core the Western Pacific Margins and the HOLOCENE WG on sub-centennial scale climate change. Results of the UK participation in this latter WG and associated coring have recently led to significant new insights into climate variability during the present (Holocene) interglacial period (eg Rohling and Pa­like (Nature; 2005) Ellison et al (Science, 2006)). Through the operation of the WG system, IMAGES can identify major scientific objectives and it accordingly prioritises and facilitates coring operations under international coordination. The critical aspect of international cooperation enhances the returns that any individual participating nation may expect in terms of ideas development, material recovery, analytical approach, and training of Early-Stage and Early-Career researchers.

  10.  A major initiative for the next five years is concerned with millennial- to sub-centennial scale variability of the Antarctic Circumpolar Current and the ensuing Atlantic-Indian water transports, including surface transports and deep water flow in order to assess the linkage of the Southern Ocean, both in terms of its thermohaline circulation and biogeochemical inventories, with millennial perturbations to the MOC and global climate. The Southern Ocean WG includes UK scientists from Cambridge, Cardiff, Edinburgh, NOCS and UEA. Other initiatives focus on the role of variations in the water exchanges between ocean basins on the global heat budget (eg, Pacific-Indian through-flow through the Indonesian Archipelago) and on variability in both the intensity and spatial extent of the tropical monsoons. The success of IMAGES coring campaigns relies on its unique capacity to recover very long Giant Piston Cores and large volume Kasten Cores. These are targeted at critical time-coverage in high accumulation settings and yield sufficient sample volume for the wide range of analytical techniques that are crucial for well-described and quantitative reconstructions of climate/ocean change.

  11.  The main achievements of IMAGES to date include over 150 international refereed publications, support of PhD students, 13 sea-going missions, 700 sediment core operations, 800 participants from over 70 institutions from the 26 participating countries (see: http://www.images-pages.org/home.html). All IMAGES related information and data are archived for public access at the World Data Centres for Marine Environmental Sciences (WDC-MARE, Bremen, Germany) and for Palaeoclimatology (Boulder, USA). IMAGES actively encourages, promotes and supports the participation of early-career scientists in its full range of activities, for example with ship-board opportunities, access to infrastructure, integration with research initiatives, and participation in workshops. Notably, ship-board opportunities are provided through the "Floating Universities Programme", one of which has been organised through the UK IMAGES community.

  12.  Funding for IMAGES activities has to date been achieved through a combination of subscriptions/donations from member countries and collective contributions of participating scientists in cruise campaigns. Currently participating countries include: Australia, Canada, Chile, People's Republic of China, Denmark, France, Germany, Iceland, India, Indonesia, Italy, Japan, Mexico, the Netherlands, New Zealand, Norway, Portugal, Russia, South Africa, Spain, Sweden, Switzerland, Taiwan, Tunisia, UK and USA.

  13.  Given its past track-record in fundamental research on climate change, and in sustaining the essential internationalisation of climate change research, the UK should ensure that it continues to support the IMAGES programme and the broader data-driven research on past ocean and climate change in a structural and substantial manner, as part of a strategic funding programme. This would perfectly complement deeper-time initiatives through IODP as well as modelling studies, to deliver an essential broad-based understanding of the magnitudes, rates, and processes of climate change. Structural support to the UK's participation to IMAGES, and to data-driven palaeoclimate research in general, will enable the UK to continue to "punch above its weight" in this critical discipline for understanding global climate change.

January 2007