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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Mirjam Kosch Florian Suter Alexander Umbricht Andy Eigenmann Slide 1
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Questions Will the present warm conditions terminate soon, to be followed by the next ice age? Will the onset of the next ice age be inhibited by the current rise in the atmospheric concentration of GHG induced by humans? Will that rise restore the warm conditions of the early Pliocene? Slide 2
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Outline 1. Methods 2. Southern Hemisphere glaciation a.Opening of the Drake Passage 3. Northern Hemisphere glaciation a.Pliocene paradoxon b.Hypotheses for Greenland glaciation 4. Questions and Discussion Slide 3
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 4
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 1. Methods Slide 5
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 18 O Terrestrial water enriched in light 16 O Seawater enriched in heavier 18 O Compare 18 O/ 16 O of sample with 18 O/ 16 O of standard (fossils) Slide 6 University of Vermont
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Neodymium Isotopes Nd ( 143 Nd/ 144 Nd) Oceanic basins with distinct Nd -values Crusts and fossil fish teeth preserve Nd -values of bottom water Bassin connections Slide 7 Wikipedia, 2009
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Ice Rafted Debris (IRD) 1. Objects deposited on/within ice shield (Debris) 2. Iceberg calves 3. Drifting and melting 4. Debris deposited onto bottom of the water body Slide 8 Wikipedia, 2009
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 2. Southern Hemisphere Glaciation Slide 9
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 10
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage Separation of South America and Antarctica Estimated opening: 49 – 17 Ma Enables Antarctic Circumpolar Current (ACC) Slide 11 Wikipedia, 2009 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – Indications Tracking Pacific Seawater Neodymium ratio Nd Pacific Nd : -3 to -5 Atlantic Nd : approximately -9 Fossil fish teeth gained from sediments High resolution of benthic Nd signal Slide 12 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 13 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 14 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 15 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 16 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – other possible Influences Weathering In general not high enough Exception: volcanic ash Slide 17 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – other possible Influences Slide 18 Scotia Sea Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – other possible Influences Weathering In general not high enough Exception: volcanic ashes Water influx from the Indian Ocean Water influx from the Panama Seaway Slide 19 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – other possible Influences Slide 20 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – other possible Influences Weather In general not high enough Exception: volcanic ashes Water influx from the Indian Ocean Water influx from the Panama Seaway Slide 21 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 22 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 The Drake Passage – Feedbacks Enhancement of nutrition upwelling Stimulation of the biological pump Lowering of the atmospheric CO 2 -concentration Possible reduction of oceanic heat flux Slide 23 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 3. Northern Hemisphere Glaciation Slide 24
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 25
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Pliocene Paradox Slide 26 Early Pliocene (5-3 Ma) showed a very different climate state even though the external forcings were practically the same as today. Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Climate in early Pliocene (5-3 Ma) Similarities with today’s climate: Intensity of sunlight incident on Earth Global geography Atmospheric concentration of CO 2 Differences with today’s climate Higher globally averaged temperatures No continental glaciers on Northern Hemisphere Sea level 25 m higher Permanent El Niño Slide 27 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Climate in late Pliocene (after 3 Ma) Cooling in the globally averaged temperatures Collapse of permanent El Niño Decreasing in atmospheric concentration of CO 2 Appearance of continental glaciers in the Northern Hemisphere Slide 28 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Slide 29
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Hypotheses for the Climate Change Panama Seaway hypothesis ENSO hypothesis Uplift hypothesis CO 2 hypothesis Slide 30 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Panama Seaway Hypothesis I Tectonically driven closure between 13 Ma and 2.5 Ma Change in salinity gradient Increase of northward heat transport Warmer, more evaporative surface water Increased atmospheric moisture More snowfall Increased ice volume in Greenland Slide 31 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Increased northward transport of warm water Increased summer temperature Increased evaporation Significantly increased snowfall Slide 32 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma Panama Seaway Hypothesis II
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Reduction of ice volume Warmer summer temperatures lead to an increased ablation Increased snowfall only leads to a small increase in ice volume Slide 33 Closed Panama Seaway Open Panama Seaway Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma Panama Seaway Hypothesis III
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 ENSO Hypothesis Permanent El Niño state during early Pliocene retarded the onset of Northern Hemisphere glaciation Loss of permanent El Niño state acted as positive forcing for the onset of glaciation Slide 34 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Key Parameters of El Niño Slide 35 Normal Pacific patternEl Niño conditions NOAA Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Today’s SST patterns Slide 36 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Conditions during early Pliocene I Slide 37 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Conditions during early Pliocene II Slide 38 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Correlation between precipitation and SST Slide 39 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 El Niño as contributor to warm conditions More convective clouds over EEP Increasing of atmospheric water vapour Reduced area covered by stratus clouds Decreasing albedo of the planet Slide 40 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Tropical-Extratropical Coupling In equilibrium the loss of heat in high latitudes balances the gain of heat in lowlatitude upwelling regions Slide 41 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Changes in Oceanic Heat Transport Slide 42 Increase in high latitude heat loss Increase in equatorial heat gain Shallower equatorial thermocline Decrease in high latitude heat loss Decrease in equatorial heat gain Deeper equatorial thermocline Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Collapse of Permanent El Niño I Due to global cooling during Cenozoic the temperature of deep ocean decreased Shoaling of the thermocline At 3 Ma BP the thermocline became so shallow that wind could bring cold water to the surface in upwelling zones Slide 43 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Only small changes in summer temperature Northward shift of the Atlantic storm track Small increase in precipitation, especially in the south Slide 44 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma Collapse of Permanent El Niño II
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Small reduction of ice volume Slide 45 Fluctuation El Niño Permanent El Niño Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma Collapse of Permanent El Niño III
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Uplift Hypothesis I Uplift of the Rocky Mountains and the Himalaya Larger Rossby Wave amplitude Jet-stream deflection Cooler air masses Slide 46 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma www.daukas.com
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Uplift Hypothesis II Cooling in Canada, North Atlantic and Greenland Generally drier climate over Greenland Northward deflection of Atlantic storm track leads to greater precipitation over southern Greenland Slide 47 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Uplift Hypothesis III Increase in snow cover Cooler summer temperatures lead to less ablation More precipitation over southern Greenland Slide 48 After tectonic uplift Before tectonic uplift Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 CO 2 Hypothesis I Decreased radiative forcing Lowered concentration of atmospheric CO 2 Cooler melt-season temperature Decreased ablation Net annual accumulation Slide 49 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 CO 2 Hypothesis II Global cooling of 1.3 °C Decrease in Greenland summer temperatures Great temperature response at high latitudes, due to albedo feedbacks Decrease in precipitation (globally and in Greenland) Slide 50 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 CO 2 Hypothesis III Large increase in ice volume Cooler summer temperatures lead to less ablation Decreased ablation dominates over decrease in accumulation Slide 51 Before decrease in CO 2 After decrease in CO 2 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 CO 2 Hypothesis Slide 52 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Summary and Questions Slide 53
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 WhenEffectsAssumed Result Closure of Panama Seaway 25 to 12 Ma BP Increased temperature More atmospheric moisture more precipitation Termination of Permanent El-Niño 5 to 3 Ma BP Stop of warming the high latitudes slightly higher temperature More precipitation Tectonic Uplift Started 65 Ma ago Important after the termination of perm. El Niño Increased Rossby Waves deflected Jet-Stream cooler Less precipitation Decrease in CO 2 Less then 3 Ma BP Clearly decreased temperatures Less evaporation less precipitation 54 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Questions Will the present warm conditions terminate soon, to be followed by the next ice age? Will the onset of the next ice age be inhibited by the current rise in the atmospheric concentration of GHG induced by humans? Will that rise restore the warm conditions of the early Pliocene? Slide 55
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Some Ideas … Solar forcing is in a (long time(?)) minimum Response to Milankovitch cycles (e.g. oscillation between ice-ages and interglacials) was weaker in times with higher GHG concentrations. Today we are not in an equilibrium state. Today‘s GHG concentrations, geological conditions and solar forcings are similar to those in early Pliocene. The equilibrium state in early Pliocene included warmer temperatures, permanent el Niño and a sealevel that was 25 m higher. What do we expect for the future? Slide 56
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Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 6.11.09 Sources Wara, M. W.; Ravelo, A. C. & Delaney, M. L. (2005), 'Permanent El Nino-Like Conditions During the Pliocene Warm Period', Science 309(5735), 758–761. DeConto, R. M.; Pollard, D.; Wilson, P. A.; Palike, H.; Lear, C. H. & Pagani, M. (2008), 'Thresholds for Cenozoic bipolar glaciation', Nature 455(7213), 652–656. Fedorov, A. V.; Dekens, P. S.; McCarthy, M.; Ravelo, A. C.; deMenocal, P. B.; Barreiro, M.; Pacanowski, R. C. & Philander, S. G. (2006), 'The Pliocene Paradox (Mechanisms for a Permanent El Nino)', Science 312(5779), 1485–1489. Lunt, D. J.; Foster, G. L.; Haywood, A. M. & Stone, E. J. (2008), 'Late Pliocene Greenland glaciation controlled by a decline in atmospheric CO2 levels', Nature 454(7208), 1102– 1105. Scher, H. D. & Martin, E. E. (2006), 'Timing and Climatic Consequences of the Opening of Drake Passage', Science 312(5772), 428–430. Sigman, D. M.; Jaccard, S. L. & Haug, G. H. (2004), 'Polar ocean stratification in a cold climate', Nature 428(6978), 59–63. Slide 57
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