GEOG5426 Megadrought I
No class October 6!
(I’m going to Boulder)
100 Views of Climate Change h p://changingclimates.colostate.edu/
Workload
A paper, not to exceed 10 pages of text plus figures
and references, which reviews the climate history of a
single...
Sco Stine California State University
Mono Lake flickr.com: kla4067
Water transfers in the American southwest




                               Courtesy Glen MacDonald
LA Aqueduct flickr.com: Aquafornia
Second LA Aqueduct at Jawbone Canyon flickr.com: Aquafornia
LA Aqueduct Filtration Plant flickr.com: Aquafornia   14
Submerged stumps in Mono Lake
Radiocarbon ages of “drought terminations Stine, Nature, 1994
Radiocarbon ages of “drought terminations Stine, Nature, 1994
* One sigma errors




Radiocarbon ages of “drought terminations Stine, Nature, 1994
“Medieval Climate Anomaly”
Submerged tree stumps in Lake Bosumtwi Ghana
Ed Cook Lamont-Doherty Earth Observatory
Ed Cook Lamont-Doherty Earth Observatory
North American Drought Atlas h   p://www.ncdc.noaa.gov/cgi-bin/paleo/pd08plot.pl
Tree-ring chronologies Cook et al., JQS, 2010
Palmer Drought Severity Index
 The PDSI incorporates historical records of precipitation
 and temperature into a water-bal...
25
The NADA grid Cook et al., Science, 2004
Drought Area Index
Observed (blue) and tree-ring (red) PDSI in ‘The West’
Tree-ring chronologies Cook et al., JQS, 2010
Tree-ring records through time Cook et al., Science, 2004
Quality of PDSI estimates from tree rings Cook et al., JQS, 2010
PDSI estimates during the Stine megadroughts Cook et al., JQS, 2010
A 1,000 years of drought in the West Cook et al., Science, 2004
“Medieval Warm Period”
What evidence do Cook et al. present to support their
 claim that the medieval period was unusually...
Dave Meko University of Arizona
Colorado River Arizona
                         Photograph: Al_HikesAZ
Water transfers in the American southwest




                               Courtesy Glen MacDonald
Colorado River Compact
                  1922
Observed discharge, Colorado River




    Compact allocation (16.5 MAF)
The history of precipitation and runoff in the
Colorado Basin as indicated by tree-rings

      Edmund Shulman
      Ph.D. ...
Relic tree, circa 323 BC Harmon Canyon, Utah
Colorado River basin tree rings Meko et al., GRL, 2007
“Natural” flow
The best estimate of river discharge in the absence of
  human modifications to the hydrological system
1,200 years of Colorado River discharge Meko et al., GRL, 2007
Drought proxies in the western US Meko et al., GRL 2007
“   The tree-ring record shows that droughts
    lasting decades have routinely gripped
    western North America.”


    ...
“   As western North America currently endures its
    worst drought since 1900, it is important to realize
    that this ...
Informal student survey
    Please don’t sign the sheets
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
Class 5, Megadrought i
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Class 5, Megadrought i

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Throughout history, drought is constant threat to societies around the world. What do proxy records tell us about the severity, extent and causes of drought during the last thousand years?

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Class 5, Megadrought i

  1. 1. GEOG5426 Megadrought I
  2. 2. No class October 6! (I’m going to Boulder)
  3. 3. 100 Views of Climate Change h p://changingclimates.colostate.edu/
  4. 4. Workload A paper, not to exceed 10 pages of text plus figures and references, which reviews the climate history of a single region over a specific time period during the Holocene (e.g., the mid-Holocene, the last 2ka or the last 500 yr).
  5. 5. Sco Stine California State University
  6. 6. Mono Lake flickr.com: kla4067
  7. 7. Water transfers in the American southwest Courtesy Glen MacDonald
  8. 8. LA Aqueduct flickr.com: Aquafornia
  9. 9. Second LA Aqueduct at Jawbone Canyon flickr.com: Aquafornia
  10. 10. LA Aqueduct Filtration Plant flickr.com: Aquafornia 14
  11. 11. Submerged stumps in Mono Lake
  12. 12. Radiocarbon ages of “drought terminations Stine, Nature, 1994
  13. 13. Radiocarbon ages of “drought terminations Stine, Nature, 1994
  14. 14. * One sigma errors Radiocarbon ages of “drought terminations Stine, Nature, 1994
  15. 15. “Medieval Climate Anomaly”
  16. 16. Submerged tree stumps in Lake Bosumtwi Ghana
  17. 17. Ed Cook Lamont-Doherty Earth Observatory
  18. 18. Ed Cook Lamont-Doherty Earth Observatory
  19. 19. North American Drought Atlas h p://www.ncdc.noaa.gov/cgi-bin/paleo/pd08plot.pl
  20. 20. Tree-ring chronologies Cook et al., JQS, 2010
  21. 21. Palmer Drought Severity Index The PDSI incorporates historical records of precipitation and temperature into a water-balance model to estimate the amount of water available in the soil relative to average conditions and is typically produced once a month.
  22. 22. 25
  23. 23. The NADA grid Cook et al., Science, 2004
  24. 24. Drought Area Index
  25. 25. Observed (blue) and tree-ring (red) PDSI in ‘The West’
  26. 26. Tree-ring chronologies Cook et al., JQS, 2010
  27. 27. Tree-ring records through time Cook et al., Science, 2004
  28. 28. Quality of PDSI estimates from tree rings Cook et al., JQS, 2010
  29. 29. PDSI estimates during the Stine megadroughts Cook et al., JQS, 2010
  30. 30. A 1,000 years of drought in the West Cook et al., Science, 2004
  31. 31. “Medieval Warm Period” What evidence do Cook et al. present to support their claim that the medieval period was unusually warm?
  32. 32. Dave Meko University of Arizona
  33. 33. Colorado River Arizona Photograph: Al_HikesAZ
  34. 34. Water transfers in the American southwest Courtesy Glen MacDonald
  35. 35. Colorado River Compact 1922
  36. 36. Observed discharge, Colorado River Compact allocation (16.5 MAF)
  37. 37. The history of precipitation and runoff in the Colorado Basin as indicated by tree-rings Edmund Shulman Ph.D. Thesis Harvard University 1944
  38. 38. Relic tree, circa 323 BC Harmon Canyon, Utah
  39. 39. Colorado River basin tree rings Meko et al., GRL, 2007
  40. 40. “Natural” flow The best estimate of river discharge in the absence of human modifications to the hydrological system
  41. 41. 1,200 years of Colorado River discharge Meko et al., GRL, 2007
  42. 42. Drought proxies in the western US Meko et al., GRL 2007
  43. 43. “ The tree-ring record shows that droughts lasting decades have routinely gripped western North America.” Jonathan Overpeck and Bradley Udall
  44. 44. “ As western North America currently endures its worst drought since 1900, it is important to realize that this drought might be nothing compared to what is possible in the future if megadrought and even ho er temperatures coincide.” Jonathan Overpeck and Bradley Udall
  45. 45. Informal student survey Please don’t sign the sheets

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