BC3 Seminars: "Global past climate changes and their regional impact", Prof. Maria Fernanda (2015-05-06)
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The document discusses the research presented by Professor Maria Fernanda Sanchez-Goñi on global past climate changes, particularly focusing on the Dansgaard-Oeschger (D-O) cycles and Heinrich events, their impacts on climate and ecosystems, and the interrelation of different Earth's reservoirs. Key findings indicate that climate variability affects vegetation patterns with notable time-lags and highlight the significant regional variability in response to abrupt climate changes. The research emphasizes the importance of understanding both orbital and sub-orbital influences on past climatic events to elucidate the dynamics of ice sheet growth and terrestrial responses during glacial transitions.
BC3 Seminars: "Global past climate changes and their regional impact", Prof. Maria Fernanda (2015-05-06)
- 1. BC3 seminars:Prof. Maria Fernanda Sanchez -Goñi, 6th of May Global past climate changes and their regional impact Maria Fernanda Sanchez Goñi Ecole Pratique des Hautes Etudes UMR CNRS-EPOC 5805, University of Bordeaux
- 2. Interglacial Last Glacial Maximum From W.F. Ruddiman, 2001 Geological archive δ18O marine record MIS5 MIS4 MIS3 MIS2 MIS1 MIS = Marine Isotope Stage MIS7 MIS9 MIS11 MIS13 MIS15 Insolation
- 3. Eccentricity: shape of the Earth’s trajectory around the Sun Obliquity: tilt of the Earth’s axis (seasonality) Precession: wobbling motion of the Earth (seasonality magnitude) Eccentricity Obliquity Precession Insolation
- 4. FromW.F.Ruddiman,2001 δ18O marine record Geological archives MIS5 MIS4 MIS3 MIS2 MIS1 Insolation
- 5. • GI characterised by different amplitude and duration • Largest temperature changes at D-O 19, 16-17, 12 and 8 • Some GS include Heinrich events (H) H1 H2 H3 H4 H5 H6 MIS 1 MIS 2 MIS 3 MIS 4 MIS 5 D-O 16-17 Dansgaard-Oeschger (D-O) cycles Cyclicity: 1,000-2,000 years (Dansgaard et al., 1984) H1 H2 H3 H4 H5 H6
- 6. Heinrich events and Heinrich stadials Cyclicity : 7,000-10,000 years (Heinrich, 1988) Ruddiman belt Outside Ruddiman belt Sanchez Goñi & Harrison, QSR, 2010 (Ruddiman, 2001)
- 8. Global impact of abrupt climate changes Ahn & Brook, Science, 2008
- 9. Abrupt climate change Change that takes place more rapidly than the underlying forcing. (Alley et al., 2002) However, as forcing is a priori unknown, abrupt change is defined as the combination of magnitude of the change and the rapidity with which is accomplished. (McManus et al., 1999; Martrat et al., 2004 SSTannual > 0.26°C/100 years) Change that takes place in less than 200 years and in magnitude exceeds the decadal variability typical of the interval in which it occurs. (Sanchez Goñi & Harrison, 2010)
- 10. Climate impact on the different Earth’s reservoirs and feedback processes D-O cycles & Heinrich events
- 11. Understanding the origin and mechanisms of any given climate change needs the knowledge of the response (nature and timing) of the different Earth’s reservoirs, and for that we need a common chronology. Climate impact on the different Earth’s reservoirs and feedback processes
- 12. M. quanta Pinus 46µm²(TL) Foraminifères Dinoflagellés G. bulloides N. pachyderma (s) IRD > 250 µ Uvigerina IRD Pollen Microcharbon Possible time-lags between the different Earth’s reservoirs in response to a given climate change Direct comparison approach: pollen in marine sediments
- 13. cold warm Herbs Pioneer Forest cold warm Herbs Pioneer Forest warm cold Is vegetation in equilibrium with rapid climate change? or Is there a time-lag between climatic change and vegetation response? « Dynamic equilibrium » « Disequilibrium hypothesis »
- 14. Dansgaard-Oeschger variability and Heinrich events Outstanding questions: •Regional expression of D-O and H events •Climatic processes •Interaction with other forcings (e.g. orbital parameters, ice volume) Heinrich events
- 15. Winter Summer
- 16. Eurosiberian region Mediterranean region MD99-2331 MD03-2697 MD01-2447 MD04-2845 MD95-2042 SU81-18 MD95-2043 International Programme
- 17. Sanchez Goñi et al., QSR, 2008
- 18. Mediterranean forest Pine Evergreen oak Olive tree Semi-desert vegetation Sagebrush Ephedra Chenopods
- 20. Fletcher & Sanchez Goñi,QR, in press Fletcher & Sanchez Goñi,QR, 2008 8 12
- 21. MD99-2331 Sanchez Goñi et al., QSR, 2008
- 23. D-O 8 H4 D-O 8 H4 MD99-2331 MD04-2845 MD95-2042 MD95-2043 Sanchez Goñi et al., QSR, 2008
- 24. 12°C 18°C Temperate forest * Synchroneity between SST and vegetation changes in western Europe in response to the millennial-scale climatic variability * The impact of the D-O climatic variability on western European ecosystems is spatially variable modified after Van Campo, 1984
- 25. Pearson correlation coefficient = 0.755 Methane & Climate Sanchez Goñi et al., QSR, 2008
- 27. Vegetation Response to Millennial-scale Variability during the Last Glacial (2010) M.F. Sanchez Goñi & S. P. Harrison Contributors: P. G. Bartlein, A.-L Daniau, L. Dupont, W. Fletcher, R. Hayashi, I. Hessler, Y. Igarashi, G. Jiménez-Moreno, S. van der Kaars, M. Kageyama, P. Kershaw, M.P. Ledru, A. Paul, H. Takahara, C. L. Whitlock, E. Wolff D. Magri, V. Margari, U. Müller B. Huntley, J. R. M. Allen, R. Cheddadi, N. Combourieu-Nebout, F. Naughton, E. Novenko, K. Roucoux, P.C. Tzedakis, R. S. Anderson, S. Desprat, L. D. Grigg, E. C. Grimm, L. E. Heusser, B. F. Jacobs, C. López-Martínez, D. A. Willard, F. Kumon, S. Kawai, M. Yamamoto, T. Irino, T. Oba, J. Chappellaz, D. Roche QUEST Working Group on Abrupt Climate Changes QUEST-DESIRE Dynamics of the Earth System and the Ice-core Record
- 28. D-O 8 warming (38 ka) ΔT =14°C in Greenland, high CH4 Harrison, Sanchez Goñi, QSR, 2010 Temperature Precipitation
- 29. Rapid, ~100 years, and synchronous vegetation/atmosphere response in western Europe to SST changes and D-O cycles. Freshwater input is associated with strong forest reduction Contrasting latitudinal impact of D-O variability modulated by orbital parameters: below 40°N (Mediterranean region): strong D-O 17-16 (~60 ka) et D-O 8 (~38 ka) above 40°N strong D-O 14 (~52 ka) et D-O 12 (~45 ka) Strong link between the Mediterranean climate and Asian monsoon Conclusions 1
- 30. Rapid ice sheet growth in the North Atlantic high latitudes at the MIS 5a/4 transition Ice volume MIS 5 MIS 4
- 32. The last interglacial-glacial transition (~80-70 kyrs BP) C20 C19 C18’ D-O21 D-O20 D-O19 Ice volume changes Millennial-scale variability Cooling Warming
- 33. • Do data confirm model predictions and, in particular, the warm sea – cold land thermal gradient at the time of ice growth? • How this orbitally-controlled ice growth is affected by the sub- orbital climatic variability, i.e. Dansgaard-Oeschger (D-O) cycles and Heinrich events?
- 35. At orbital scale cold land warm sea Sanchez Goñi et al., Nat. Geosci., 2013
- 36. At sub-orbital scale C20C19C18’ Warm surface currents Moisture transport Icebergs
- 37. Sanchez Goñi et al., Nat. Geosci., 2013 At sub-orbital scale
- 38. Conclusions 2 • Our data provide strong evidence for a rapid ice growth scenario involving both orbital and sub-orbital increases of air-sea thermal contrast at the MIS 5a/4 transition • A warm pool in the western European margin during the North Atlantic cold events of the MIS5a/4 transition, C20, C19 and C18’. • The tight coupling between marine and terrestrial responses to the millennial-scale cycles is not a pervasive feature throughout the Quaternary in the western European margin as previously thought
- 39. EPHE laboratory Paleoclimatology and Marine Paleoenvironments