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The "Year Without A Summer" was not a year without a ring

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The Tambora eruption of 1815 cooled the planet and caused the "Year Without A Summer" in western Europe and eastern North America. But was it cold enough to cause trees across the Northern Hemisphere to skip a ring?

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The "Year Without A Summer" was not a year without a ring

  1. 1. The “Year Without a Summer” WAS NOT a year without a ring Sco! St. George University of Minnesota
  2. 2. The 1815 eruption of Mount Tambora is estimated to be the largest volcanic event in recorded history.
  3. 3. Ashfall from the 1815 eruption extended more than 1,300 km away from Tambora. Source: Wikipedia User Indon
  4. 4. Source: Desert Research Institute
  5. 5. Source: Dai et al, Journal of Geophysical Research, 1991
  6. 6. Sulfate aerosols emi!ed by Pinatubo
  7. 7. “ ” Severe frosts occurred [in Massachuse!s] every month; June 7th and 8th snow fell, and it was so cold that crops were cut down, even freezing the roots… Atkins, 1887 History of Hawley
  8. 8. Early 19th century temperature observations show 1-2°C cooling in central Europe and the eastern United States between AD 1815 and 1816. Source: D’Arrigo et al., Journal of Geophysical Research, 2013
  9. 9. 1816 THE “YEAR WITHOUT A SUMMER”
  10. 10. MODELS PROXIES -2°C -1°C
  11. 11. Michael Mann and colleagues used numerical simulations of climate and tree growth to show that when temperatures fall abruptly for one or two growing seasons, trees in these regions undergo li!le or no growth. “ ” Nature Geoscience press release February 2012
  12. 12. A.D. 1259 A.D. 1816
  13. 13. “IF NO RING WAS FORMED IN A GIVEN YEAR, ” THAT CREATES A FURTHER COMPLICATION, INTRODUCING AN ERROR IN THE CHRONOLOGY ESTABLISHED BY COUNTING RINGS BACK IN TIME. Dr. Michael Mann Penn State News, February 6, 2012
  14. 14. ‘LOCALLY-ABSENT’ RING
  15. 15. The cambium of trees of many species may be locally dormant, in the sense that no new cells are produced, throughout one or more growing seasons. “ ” Edmund Schulman Ecology, 1941
  16. 16. 1807 1808 1809 1811 1812 Source: Sarah Appleton
  17. 17. ?COULD THE GLOBAL TREE-RING NETWORK CONTAIN WIDESPREAD (BUT UNRECOGNIZED) ‘MISSING’ RINGS?
  18. 18. Large sets of ring-width data have provided the foundation for many proxy estimates of regional or global surface temperature. Source: Intergovernmental Panel on Climate Change, AR5, Working Group 1
  19. 19. The Monsoon Asia Drought Atlas generated yearly maps of drought severity Source: Cook et al., Science, 2010 based on ring-width and other tree-ring measurements.
  20. 20. Surrogate estimates of discharge have been used to produce ‘worst-case’ scenarios for water supplies in major western rivers, including the Colorado. Source: Meko et al., Geophysical Research Le!ers, 2007
  21. 21. ±0
  22. 22. BEvidence against the ‘missing ring’ hypothesis
  23. 23. OTHER CHRONOLOGICAL EVIDENCE BOREAL TREES AND MISSING RINGS EXTRATERRESTRIAL CONFIRMATION
  24. 24. AThe Northern Hemisphere tree-ring network
  25. 25. The International Tree-Ring Database holds more than 3,200 records Pinus Picea Quercus Pseudotsuga Larix Nothofagus Austrocedris Phyllocladus Agathis Source: St. George, PAGES News, 2014 from every continent except Antarctica.
  26. 26. Source: Phil Camill
  27. 27. Source: Uday Kunwar Thapa
  28. 28. Fri!s, H.C. Growth-rings of trees: their correlation with climate. Science 154, 973-975 (1966).
  29. 29. -0.8 -0.6 -0.4 -0.2 +0.2 +0.4 +0.6 +0.8 correlation coefficient (ring-width vs. local climate)
  30. 30. (a) Winter precipitation WINTER PRECIPITATION Source: St. George, Quaternary Science Reviews, 2014
  31. 31. Source: Kevin Anchukaitis
  32. 32. (c) Summer temperature SUMMER TEMPERATURE -0.8 -0.6 -0.4 -0.2 +0.2 +0.4 +Source: St. George, Quaternary Science Reviews, 2014
  33. 33. The International Tree-Ring Database holds more than 3,200 records Pinus Picea Quercus Pseudotsuga Larix Nothofagus Austrocedris Phyllocladus Agathis Source: St. George, PAGES News, 2014 from every continent except Antarctica.
  34. 34. ?COULD THE GLOBAL TREE-RING NETWORK CONTAIN WIDESPREAD (BUT UNRECOGNIZED) ‘MISSING’ RINGS?
  35. 35. BEvidence against the ‘missing ring’ hypothesis
  36. 36. OTHER CHRONOLOGICAL EVIDENCE BOREAL TREES AND MISSING RINGS EXTRATERRESTRIAL CONFIRMATION
  37. 37. Adding an ‘absent ring’ to a tree-ring sequence causes the dates of all prior rings to be pushed back by one year.
  38. 38. Source: Alexandra Witze
  39. 39. 1783 THE LAKI (ICELAND) ERUPTION
  40. 40. Source: St. Thomas Productions
  41. 41. During several of the summer months of the year 1783, when the effect of the sun's rays to heat the earth in these northern regions should have been greater, there existed a constant fog over all Europe, and a great part of North America. “ ” Benjamin Franklin Memoirs of the Literary and Philosophical Society of Manchester, 1784
  42. 42. Across Alaska and northwestern Canada, trees formed wood much less dense than normal during the AD 1783 growing season. Source: Jacoby et al., Quaternary Science Reviews, 1999
  43. 43. Reconstructed summer temperatures for Alaska (estimated from latewood density) was more than 4 s.d. below the long-term mean. Source: Jacoby et al., Quaternary Science Reviews, 1999
  44. 44. Source: Briffa et al., The Holocene, 2002
  45. 45. IF 1816 IS MISSING THEN 1783 ➜ 1782
  46. 46. Source: Esper et al., Dendrochronologia, 2013
  47. 47. If tree-ring records from Europe are shi$ed back one year, their strong correlation with long temperature records disappears. Source: Esper et al., Dendrochronologia, 2013
  48. 48. OTHER CHRONOLOGICAL EVIDENCE BOREAL TREES AND MISSING RINGS EXTRATERRESTRIAL CONFIRMATION
  49. 49. Max Torbenson University of Arkansas
  50. 50. HOW ?OFTEN DO TREES FORM LOCALLY-ABSENT RINGS AND WHY?
  51. 51. 1,063 RECORDS HAD AT LEAST ONE ABSENT RING. 1,296 RECORDS DID NOT HAVE A SINGLE ABSENT RING.
  52. 52. 1816 0% 20% 40% 60% 80% 100% Intensity of locally-absent rings 1259 1453 Source: St. George et al., Geophysical Research Le!ers, 2013
  53. 53. Pinus Picea Pseudotsuga Quercus Larix a 36ºN 18ºN 54ºN 72ºN 90ºN 0º 180ºW 120ºW 60ºW How o$en have locally-absent rings occurred in the Northern Hemisphere tree ring-width network?
  54. 54. 0% 2% 4% 6% 8% 80°N 60°N 40°N 20°N Latitude Percentage of locally-absent rings b Picea Quercus Pinus Pseudotsuga Larix Other genera Source: St. George et al., Geophysical Research Le!ers, 2013
  55. 55. PICEA LARIX (spruce) (larch)
  56. 56. Source: Phil Camill
  57. 57. ZERO CASES WHERE A GROWTH RING WAS MISSING FROM EVERY TREE AT THE SAME SITE. 134 881 TREE-RING ‘YEARS’
  58. 58. MANY (OR MOST) TEMPERATURE-LIMITED FOREST STANDS IN THE NORTHERN HEMISPHERE WOULD NEED TO SHOW A REACTION TO THERMAL STRESS THAT HAS (ESSENTIALLY) NEVER BEEN OBSERVED ANYWHERE.
  59. 59. OTHER CHRONOLOGICAL EVIDENCE BOREAL TREES AND MISSING RINGS EXTRATERRESTRIAL CONFIRMATION
  60. 60. Source: Miyake et al., Nature, 2012 The 14C content of Japanese cedar tree rings increased by 1.2% from AD 774 to 775.
  61. 61. We’d expect these [supernovae and superflares] to be global events that would appear in the radiocarbon of any long tree-ring chronology around the world. “ ” Kevin Anchukaitis National Geographic, June 7, 2011
  62. 62. Radiocarbon measurements of a subfossil pine (Pinus cembra) show the same 1.2% increase in 14C from AD 774 to 775. Source: Büntgen et al., Nature Climate Change, 2014
  63. 63. “ ALL STUDIES ” DEMONSTRATE THE PRECISION OF TREE-RING DATING BACK TO THE YEAR 775. Büntgen et al., Nature Climate Change, 2014
  64. 64. MODELS PROXIES -2°C -1°C
  65. 65. None of this is to say that there are not challenges associated with using tree ring proxies to identify and evaluate the timing and environmental consequences of volcanic eruptions. “ ” D’Arrigo et al., 2013 Journal of Geophysical Research
  66. 66. ?COULD THE GLOBAL TREE-RING NETWORK CONTAIN WIDESPREAD (BUT UNRECOGNIZED) ‘MISSING’ RINGS?

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