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?

1. The “Year Without a Summer”
WAS NOT
a year without a ring
Sco! St. George
University of Minnesota

3. The 1815 eruption of Mount Tambora is estimated to be the largest volcanic event
in recorded history.

4. Ashfall from the 1815 eruption extended more than 1,300 km away from Tambora.
Source: Wikipedia User Indon

5. Source: Desert Research Institute

6. Source: Dai et al, Journal of Geophysical Research, 1991

7. Sulfate aerosols emi!ed by Pinatubo

8. “ ”
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

9. 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

10. 1816 THE “YEAR WITHOUT A SUMMER”

13. MODELS PROXIES
-2°C -1°C

14. 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

15. A.D. 1259 A.D. 1816

16. “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

17. ‘LOCALLY-ABSENT’
RING

19. 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

20. 1807 1808 1809 1811 1812
Source: Sarah Appleton

22. ?COULD
THE GLOBAL TREE-RING NETWORK
CONTAIN
WIDESPREAD
(BUT UNRECOGNIZED)
‘MISSING’ RINGS?

23. 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

24. 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.

25. 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

26. ±0

28. BEvidence against the ‘missing ring’ hypothesis

29. OTHER
CHRONOLOGICAL
EVIDENCE
BOREAL TREES
AND MISSING RINGS
EXTRATERRESTRIAL
CONFIRMATION

30. AThe Northern Hemisphere tree-ring network

38. 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.

39. Source: Phil Camill

40. Source: Uday Kunwar Thapa

42. Fri!s, H.C. Growth-rings of trees: their correlation with climate. Science 154, 973-975 (1966).

43. -0.8 -0.6 -0.4 -0.2 +0.2 +0.4 +0.6 +0.8
correlation coefficient
(ring-width vs. local climate)

44. (a) Winter precipitation
WINTER PRECIPITATION
Source: St. George, Quaternary Science Reviews, 2014

46. Source: Kevin Anchukaitis

48. (c) Summer temperature
SUMMER TEMPERATURE
-0.8 -0.6 -0.4 -0.2 +0.2 +0.4 +Source: St. George, Quaternary Science Reviews, 2014

50. 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.

51. ?COULD
THE GLOBAL TREE-RING NETWORK
CONTAIN
WIDESPREAD
(BUT UNRECOGNIZED)
‘MISSING’ RINGS?

52. BEvidence against the ‘missing ring’ hypothesis

53. OTHER
CHRONOLOGICAL
EVIDENCE
BOREAL TREES
AND MISSING RINGS
EXTRATERRESTRIAL
CONFIRMATION

54. Adding an ‘absent ring’ to a tree-ring sequence
causes the dates of all prior rings to be pushed back by one year.

55. Source: Alexandra Witze

56. 1783 THE LAKI (ICELAND) ERUPTION

57. Source: St. Thomas Productions

58. 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

59. 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

60. 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

61. Source: Briffa et al., The Holocene, 2002

62. IF 1816 IS MISSING
THEN 1783 ➜ 1782

63. Source: Esper et al., Dendrochronologia, 2013

64. 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

65. OTHER
CHRONOLOGICAL
EVIDENCE
BOREAL TREES
AND MISSING RINGS
EXTRATERRESTRIAL
CONFIRMATION

66. Max Torbenson University of Arkansas

67. HOW ?OFTEN
DO TREES FORM
LOCALLY-ABSENT RINGS
AND WHY?

69. 1,063 RECORDS
HAD AT LEAST ONE
ABSENT RING.
1,296 RECORDS
DID NOT HAVE
A SINGLE
ABSENT RING.

70. 1816
0% 20% 40% 60% 80% 100%
Intensity of locally-absent rings
1259 1453
Source: St. George et al., Geophysical Research Le!ers, 2013

71. 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?

72. 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

74. PICEA LARIX
(spruce) (larch)

75. Source: Phil Camill

76. ZERO CASES WHERE A GROWTH RING WAS MISSING
FROM EVERY TREE AT THE SAME SITE.
134 881 TREE-RING ‘YEARS’

77. 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.

78. OTHER
CHRONOLOGICAL
EVIDENCE
BOREAL TREES
AND MISSING RINGS
EXTRATERRESTRIAL
CONFIRMATION

80. Source: Miyake et al., Nature, 2012
The 14C content of Japanese cedar tree rings increased
by 1.2% from AD 774 to 775.

81. 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

83. 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

86. “ ALL STUDIES
”
DEMONSTRATE THE PRECISION
OF TREE-RING DATING
BACK TO THE YEAR 775.
Büntgen et al., Nature Climate Change, 2014

88. MODELS PROXIES
-2°C -1°C

89. 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

90. ?COULD
THE GLOBAL TREE-RING NETWORK
CONTAIN
WIDESPREAD
(BUT UNRECOGNIZED)
‘MISSING’ RINGS?