GEOG3839.13, Global temperature reconstructions
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This document discusses the use of tree ring data to reconstruct past climate conditions. It describes principal component analysis (PCA) which is used to group tree ring data into components representing different climate influences. Linear regression models are then used to relate the principal components to temperature. The document discusses several global temperature reconstructions produced using long tree ring records and how they indicate periods of warmth like the Medieval Warm Period and cooler periods like the Little Ice Age. It also describes the "divergence problem" where some tree ring data no longer correlate as strongly with modern temperatures.
![“ ...this study provides evidence for intervals of
significant warmth in the [Northern Hemisphere]
within the so-called Medieval Warm Period and for
significantly colder intervals during the so-called
”
Li le Ice Age period.
— Osborne and Briffa, 2006](https://image.slidesharecdn.com/class13globaltemperaturereconstructions-110310120048-phpapp01/85/GEOG3839-13-Global-temperature-reconstructions-24-320.jpg)
GEOG3839.13, Global temperature reconstructions
- 1. Source: St. George and Luckman, 2001
- 2. Source: St. George and Luckman, 2001
- 3. Source: St. George and Luckman, 2001
- 4. a.k.a. Empirical Orthogonal Function analysis PRINCIPLE COMPONENTS ANALYSIS
- 7. PC1 (group 1) PC3 (group 3) PC2 (group 2)
- 8. Source: St. George and Luckman, 2001
- 9. Source: St. George and Luckman, 2001
- 10. most sites Source: St. George and Luckman, 2001
- 11. most sites farthest north Source: St. George and Luckman, 2001
- 12. most sites farthest north unusual site Source: St. George and Luckman, 2001
- 14. yt = axt + b + ε
- 15. Tjj = 0.23PC1 + -0.23PC3t+1 + 0.16PC2t+1 + -0.09PC1t+1 + -0.46
- 16. Source: St. George and Luckman, 2001
- 17. “ Tree-ring-derived records have played a prominent role in a empts to establish how climate has varied ” in the recent past. — Jones et al., The Holocene, 2009
- 18. G L O B A L T E M P E R AT U R E R E C O N S T R U C T I O N S Photograph: Marianna
- 19. Long, temperature-sensitive tree-ring records have been used to estimate average temperatures across the entire hemisphere or globe. Source: Esper et al., Science, 2002
- 20. Source: Esper et al., Science, 2002
- 21. Source: D’Arrigo et al., 2006
- 22. Source: D’Arrigo et al., 2006
- 23. Source: Osborne and Briffa, 2006
- 24. “ ...this study provides evidence for intervals of significant warmth in the [Northern Hemisphere] within the so-called Medieval Warm Period and for significantly colder intervals during the so-called ” Li le Ice Age period. — Osborne and Briffa, 2006
- 26. Source: Intergovernmental Panel on Climate Change, 2007
- 28. “ Tree-rings also allow the reconstruction of large-scale regional or global temperature pa erns defined by large networks of chronologies. ”— Brian Luckman
- 29. Source: Briffa et al., Global and Planetary Change, 2004
- 31. 1883 “THE LOUDEST SOUND IN MODERN HISTORY”
- 34. 1816 THE “YEAR WITHOUT A SUMMER”
- 35. Mount Tambora, Indonesia Its eruption in 1815 was the most explosive since AD 180
- 36. Source: Briffa et al., Global and Biological Change, 2004
- 39. “Trees are not thermometers or rain gagues.” Keith Briffa and colleagues
- 41. the ‘divergence problem’ is defined as the tendency for tree growth at some previously temperature-limited northern sites to demonstrate a weakening in mean temperature response in recent decades. Source: D’Arrigo et al., 2008
- 42. Source: D’Arrigo et al., 2008
- 43. “ It is important to stress that not all high-latitude regions display this apparent decoupling between observed and dendroclimatically estimated temperatures. ” — Jones et al., The Holocene, 2009
- 44. Source: Briffa et al., Global and Biological Change, 2004
- 45. Source: D’Arrigo et al., 2008
- 47. SURFACE TEMPERATURE RECONSTRUCTIONS FOR T H E LAS T 2 , 00 0 Y E A R S NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES