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Greg Retallack - The Once and Future Global Cooling: Lessons from Prehistory

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Greg Retallack - The Once and Future Global Cooling: Lessons from Prehistory

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Greg Retallack - The Once and Future Global Cooling: Lessons from Prehistory
From Biodiversity for a Livable Climate conference: "Restoring Ecosystems to Reverse Global Warming"
Saturday November 22nd, 2014
www.bio4climate.org

Greg Retallack - The Once and Future Global Cooling: Lessons from Prehistory
From Biodiversity for a Livable Climate conference: "Restoring Ecosystems to Reverse Global Warming"
Saturday November 22nd, 2014
www.bio4climate.org

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Greg Retallack - The Once and Future Global Cooling: Lessons from Prehistory

  1. 1. TThhee oonnccee aanndd ffuuttuurree gglloobbaall ccoooolliinngg:: lleessssoonnss ffrroomm pprreehhiissttoorryy GGrreeggoorryy JJ.. RReettaallllaacckk UUnniivveerrssiittyy ooff OOrreeggoonn Eocene-Oligocene paleosols Badlands National Park, South Dakota
  2. 2. GGrraassssllaanndd eexxppaannssiioonn cchhaannggeedd tthhee wwoorrlldd SSiinnccee 3355 MMaa,, 00--2255%% ooff llaanndd,, bbuutt nnoott AAnnttaarrccttiiccaa Crumb structure (mollic epipedon) in tall grassland paleosol (Mollisol) Dayville, OR: late Miocene (7 Ma)
  3. 3. Smell the grass Grassland soil (Mollisol) Lake Nakuru National Park, Kenya cis-3-hexenal carbon gray, hydrogen white, oxygen red
  4. 4. QUATERNARY RECORD 1: PALEOSOLS Quaternary Palouse Loess, eastern Washington Paleosols near Kahlotus, WA, data from Busacca (1998) Paleosols near Dayton, WA
  5. 5. QUATERNARY 2: SOIL TYPES Palouse Loess near Clyde, Washington, alternation of interglacial deep-calcic grassland and glacial shallow-calcic sagebrush Mt St Helens ash S 23.7 ka 36.1 ka 40.1 ka 46.2 ka Mt St Helens ash C thermoluminescence dates from Busacca (1998) Also in paleosols, are fossil mam-mals (Rensberger & Barnosky, 1993), & phytoliths (Blinnikov et al Earthworm fabric in 46 ka Nix grassland paleosol Taenidium (cicada) burrow in 40 ka Tlal sagebrush paleosol 2002)
  6. 6. QUATERNARY 3: ECOSYSTEM SHIFTS Modern dry grassland near Benge, Washington Modern sagebrush near Denio, Nevada
  7. 7. CENOZOIC 1: PALEOSOLS IN DEEP TIME Longview Ranch, Oregon, with green Oligocene paleosols in hill
  8. 8. CENOZOIC 2:JOHN DAY FM OLIGOCENE Well dated (Ar/Ar, paleomagnetic) fossiliferous sequence
  9. 9. CENOZOIC 3: SHRUB/GRASS TRACES Taenidium cicada burrow of sagebrush Edaphichnium earthworm chimney of grassland Pallichnus dung beetle nests of grassland
  10. 10. CENOZOIC 4: VEGETATION FROM SOIL Blocky structure red forested paleosol (Alfisol), Painted Hills, OR: Oligocene (31 Ma) Crumb structure (mollic epipedon) in tall grassland paleosol (Mollisol) Dayville, OR: late Miocene (7 Ma) Crumb structure (mollic epipedon) in short grassland paleosol (Mollisol) Kimberly, OR: mid-Miocene (19 Ma) Merychippus seversus Dayville, OR: mid-Miocene (16 Ma)
  11. 11. CENOZOIC 5: VEGETATION PALEOSOLS -bunch then sod grasslands at warm-wet times -dry times expanded sagebrush (not grassland) PHYTOLITHS -36-0 Ma abundant grassland phytoliths (Strömberg, 2002, 2004) PEDOGENIC δ13Ccarb -40 Ma of 20-40% C4 (Fox and Koch, 2003)
  12. 12. CENOZOIC 6: CLIMATE FROM SOIL Red forested non-calcareous paleosols (Alfisols) pass upwards into brown calcareous grassland paleosols (Andisols) by mid-Oligocene (30Ma) Painted Hills, Oregon Paleoprecipitation estimated from paleosol Bt (blue) or Bk (red) follows decline in atmospheric CO2
  13. 13. CLIMATE 1: TRANSIENT SPIKES Chesapeake impact structure 35 Ma (from Voytek, 2005) 35 Ma (Priabonian) and 16 Ma (Langhian) transient spikes of warm-wet CO2 due to impacts and flood basalts Columbia River Basalts, Oregon, Washington (17-15 Ma) (Camp and Ross 2004) Steinheim Crater, Germany 15 ma (3.8 km) by E. Stabenow Ethiopian flood basalts 35 Ma (from Wood and Guth 2010)
  14. 14. CLIMATE 2: HIMALAYAN COOLING? PRO. Mountain uplift promotes weathering and albedo (Ruddiman and Raymo 1988) CON. Physical not chemical weathering, metamorphic CO2
  15. 15. CLIMATE 3: ANTARCTIC CURRENT? PRO. Thermal isolation ices Antarctica, consumes H2O, raises albedo (Kennett 1978) CON. Warms mid-latitudes, minor reductions of atmospheric H2O, CO2 and albedo
  16. 16. CLIMATE 4: GRASSLAND EXPANSION? Grasslands not due to drying, expanding into wetter regions -from 35-0 Ma expanded from 0-25% of land Mollic and near-mollic paleosol records from 3 continents (Retallack 2001)
  17. 17. COEVOLUTION 1: GRASSES-GRAZERS BIOLOGICAL MECHANISM -adaptation to others not to environment -grasses best withstand grazers -grazers best cope with phytoliths and growth of grasses from Retallack 2007
  18. 18. COEVOLUTION 2: PACK HUNT & HERDS Paratomarctus euthos middle Miocene, Valentine Formation, Gordon Quarry, Nebraska Hesperocyon gregarius 32 Ma Mesocyon sp. 27 Ma Tomarctus euthos 16 Ma Canis meso-melas (living) 5 cm from Radinsky 1969 Prorean gyrus -prorean gyrus found in pack hunting wolves and dogs, not foxes -prorean gyrus appears in boro-phagine dogs of Nebraska 19 Ma
  19. 19. COEVOLUTION 4: DUNG AND SOD Agate Springs, NE: Miocene (19Ma) by Jay Matternes bear dog den (Daphaenodon) Mollisol paleosol Silica husk of grass (Panicum elegans) cursorial, hypsodont, tridactyl (Parahippus tyleri) Dung cake of ruminant - pack hunting - running escape - prey herding - hypsodont grazing - siliceous grasses - dung cakes - weedless sod - mollic soil
  20. 20. COOLING 1: CARBON STORAGE - organic C like net primary productivity increases with precipitation -grasslands rule strategic zone (300-1200 mm mean annual precip.) African grasslands Mean annual precipitation (mm) Soil organic carbon (kg/m2) Australia from Wynn et al. 2005, Africa from Zinke et al 1984 y = 1.7492Ln(x) - 8.4142 R2 = 0.7439 12 10 8 6 4 2 0 Australian woodlands 0 500 1000 1500 2000 2500 3000 3500 4000
  21. 21. COOLING 2: TRANSPIRATION - grasslands have moist soil, dry air -woodlands have drier soil (20-30%), moist air -water vapor is a green-house gas, although easily rained out Nairobi National Park, Kenya Kakamega Forest, Kenya
  22. 22. COOLING 3: ALBEDO - grasslands light (albedo 15-19 %), covered by snow (albedo 40-85%) -woodlands dark (albedo 8-13%) hard to cover with snow
  23. 23. CARBON FARMING 1: MOTIVATION - global warming due to CO2 could be offset by C storage in farm soils -tests already underway in Australia, baseline soil C assay, then carbon credit payment for gains
  24. 24. CARBON FARMING 2: TECHNIQUES 1. CELL GRAZING Pen cattle with electric for each days grazing: grazing takes out weeds leaving sod grasses. 2. PASTURE CROPPING Drill seed and raise crop through sod: prevents soil oxidation by plowing. 3. CONTOUR COPPICING Plant trees at inflexion point in slopes: prevents Electric fence and cell grazing, Horsham, Victoria gully erosion.
  25. 25. CONCLUSIONS There’s some good news beneath the horizon, Next to swamps, grassland soils have more carbon, Since these are the soils that we already use We can manage soil carbon and curb soil abuse, It was just coevolution, a process by which we got sod. By grazing so hard on grassy sward, The Ice Age no longer seems odd. Still we have coevolution, a way that we can go forth And use the soil against big oil To try to cool the Earth. Grassland soil (Mollisol), Dionysiou, central Greece.

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