Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Mirjam Kosch Florian Suter Alexander Umbricht Andy Eigenmann Slide 1

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 4

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Methods Slide 5

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation  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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Southern Hemisphere Glaciation Slide 9

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 10

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 13 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 14 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 15 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 16 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 22 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Northern Hemisphere Glaciation Slide 24

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 25

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Slide 29

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation  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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation  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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation  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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation  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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation CO 2 Hypothesis Slide 52 Eocene 55.8 – 33.9 MaOligocene 33.9 – 23 MaMiocene 23 – 5.33 MaPliocene 5.33 – 2.59 Ma

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation Summary and Questions Slide 53

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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

Paleoclimatology and Climate History – HS 2009 Pliocene, El Niño and Northern / Southern Hemisphere Glaciation 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–  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