QUIGS - PAGES-PMIP Working Group on Quaternary Interglacials
Past interglacials can be thought of as a series of natural experiments in which boundary conditions, e.g. the seasonal and latitudinal distribution of insolation, the extent of continental ice sheets and atmospheric greenhouse gas concentrations, varied considerably with consequent effects on the character of climate change. Documenting interglacial climate variability, can therefore provide a deeper understanding of the physical climate responses to underlying forcing and feedbacks, and of the capabilities of Earth System Models to capture the patterns and amplitudes of the responses.
These considerations provided the impetus for a comprehensive comparison of interglacials conducted by the the PAGES Working Group on Past Interglacials (PIGS) which ran from 2008-2015.
While PIGS encapsulated the current state of the art in its synthesis work, "Interglacials of the last 800,000 years", it also identified a number of research issues that need to be solved if further breakthroughs in understanding recent interglacials are to be made, these include:
1. There is no simple astronomical cause for differences in the intensity of interglacials, which seems to arise at least partly from the pattern of CO2. This emphasizes the need to better understand and model the carbon cycle across glacial cycles.
2. Chronological advances, both in assessing absolute ages relative to astronomical forcing, and in aligning different proxies and locations, are essential if we are to assess the dynamics of interglacials and their termination and inception.
3. The paucity of terrestrial records hampers the assessment of many important aspects of climate.
4. Although existing records suggest that sea level is quasi-similar at the apex of each post-800 ka interglacial, further data are essential, both to understand the pattern of ice sheet forcing of climate, and to define the questions that need to be asked about the state of the Greenland and Antarctic ice sheets in warmer interglacials.
5. Identifying the controls on intra-interglacial variability remains a challenge.
Within the so-called "zoo" of interglacials, the Last Interglacial (LIG, MIS 5e) has been the most intensively studied, but modeling of earlier interglacials has been quite limited. Much more needs to be done to better characterize and understand the other interglacials: MIS 11, the cool versus warm interglacials of the last 800 kyrs, and interglacials in the 41kyr-world vs those in the 100kyr-world (Fig 1).
Fig 1: LR04 benthic δ18O over the Quaternary (modified from Lisiecki and Raymo, 2005).
The occurrence of interglacials with differing characteristics is an intriguing aspect of the ice ages that raises fundamental questions about the Earth’s climate. Although our understanding has improved, a general theory accounting for the timing and amplitude of interglacials remains elusive; therefore, QUIGS aims to:
1. Document and synthesize data on the temporal and spatial patterns of climate responses during Quaternary interglacials and assess the governing processes using numerical models;
2. Assess the relevance of interglacials to understanding future climate change.
Within this framework we will examine (i) warm extremes, (ii) 'cooler' interglacials, and (iii) interglacials of the Early Pleistocene '41kyr-world'.
Fig 2: Summer SST temperature anomalies from marine sediment data (dots) superimposed onto simulated July-August-September SST in the North Atlantic region. From the CCSM3 (left panel) and HadCM3 (right panel) models at 125 ka. (Capron et al. 2014).
The drive towards a systematic understanding of interglacials requires targeted model exercises as well specific data sets with improved chronologies (Fig 2; some of which are not available yet). In this respect QUIGS will promote closer collaboration between the modeling (PMIP) and data communities, who together will provide expertise on experimental design, data compilations and syntheses, model-data comparisons, and interpretation of results.
You can read more about our scientific questions and workplan for Phase 1 on our Scientific goals page.
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This group is open to anyone who is interested. To participate contact a member of the Leadership Team.
Capron E, Govin A, Stone, EJ, Masson-Delmotte V, Mulitza S, Otto-Bliesner B, Sime L, Waelbroeck C & Wolff E (2014) Temporal and spatial structure of multi-millennial temperature changes at high latitudes during the Last Interglacial Quaternary Science Reviews 103: 116-133 (link)
Lisiecki LE & Raymo ME (2005) A Pliocene- Pleistocene stack of 57 globally distributed benthic d18O records Paleoceanography 20(1): PA1003, doi:10.1029/2004PA001071 (link)