GEOG3839.13, Global temperature reconstructions
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GEOG3839.13, Global temperature reconstructions

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GEOG3839.13, Global temperature reconstructions GEOG3839.13, Global temperature reconstructions Presentation Transcript

  • Source: St. George and Luckman, 2001
  • Source: St. George and Luckman, 2001
  • Source: St. George and Luckman, 2001
  • a.k.a. Empirical Orthogonal Function analysisPRINCIPLE COMPONENTS ANALYSIS
  • PC1 (group 1) PC3 (group 3) PC2 (group 2)
  • Source: St. George and Luckman, 2001
  • Source: St. George and Luckman, 2001
  • most sitesSource: St. George and Luckman, 2001
  • most sites farthest northSource: St. George and Luckman, 2001
  • most sites farthest north unusual siteSource: St. George and Luckman, 2001
  • LINEARREGRESSION
  • yt = axt + b + ε
  • Tjj = 0.23PC1 + -0.23PC3t+1 + 0.16PC2t+1 + -0.09PC1t+1 + -0.46
  • Source: St. George and Luckman, 2001
  • “ 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
  • 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 SPhotograph: Marianna
  • 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
  • Source: Esper et al., Science, 2002
  • Source: D’Arrigo et al., 2006
  • Source: D’Arrigo et al., 2006
  • Source: Osborne and Briffa, 2006
  • “ ...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
  • LINEARREGRESSION
  • Source: Intergovernmental Panel on Climate Change, 2007
  • Photograph: Mark Anbinder
  • “ Tree-rings also allow the reconstruction of large-scale regional or global temperature pa erns defined by large networks of chronologies. ”— Brian Luckman
  • Source: Briffa et al., Global and Planetary Change, 2004
  • h p://www.cru.uea.ac.uk/cru/people/briffa/temmaps/
  • 1883“THE LOUDEST SOUND IN MODERN HISTORY”
  • Krakatau, Indonesia 1883
  • h p://www.cru.uea.ac.uk/cru/people/briffa/temmaps/
  • 1816THE “YEAR WITHOUT A SUMMER”
  • Mount Tambora, Indonesia Its eruption in 1815 was the most explosive since AD 180
  • Source: Briffa et al., Global and Biological Change, 2004
  • h p://www.cru.uea.ac.uk/cru/people/briffa/temmaps/
  • Huaynaputina Peru
  • “Trees are not thermometers or rain gagues.” Keith Briffa and colleagues
  • THEDIVERGENCE PROBLEM
  • 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
  • Source: D’Arrigo et al., 2008
  • “ 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
  • Source: Briffa et al., Global and Biological Change, 2004
  • Source: D’Arrigo et al., 2008
  • SURFACE TEMPERATURERECONSTRUCTIONSFOR T H E LAS T 2 , 00 0 Y E A R S NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES