What do tree rings tell us about drought and climate ... - Colorado

Prehistoric Context for
Western Drought
Histories of
Climate
Fire
Insect
outbreaks
Tree
demography
Julio Betancourt, Steve Gray
Greg McCabe, Hugo Hidalgo
GreatDrought
AD1266-1299
AD1266 1299
Cross-dating
Last beam
cut in
AD 1286
Betatakin

NE Utah Monthly Precipitation 1895-2002
1895 2002

July-July Precipitation (cm)
Tree-Ring Tree Ring width series capture both interannual
and interdecadal variations in climate
Calibration for the NE Utah/SW Wyoming Precipitation Reconstruction
35
30
25
20
15
Observed vs
10
Predicted
1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 1995

Coronado’s
Entrada
?
Significant Cultural Events

Connie Woodhouse
www.ncdc.noaa.gov/paleo/streamflow

Ni, Cavazos, Hughes, Comrie & Funkhouser (2002)
http://www.ngdc.noaa.gov/paleo/
November-April precipitation (mm)
140
120
100
80
60
40
20
0
1000 1200 1400 1600 1800 2000

http://www.ngdc.noaa.gov/paleo/

Some applications of tree-ring tree ring data
towards understanding drought
- structure of droughts
- how representative is instrumental record?
- worst and best-case scenarios for management
- geography of drought
- patterns and sources of synchroneity of
decadal to centennial oscillations at
regional to subcontinental scales
- temperature reconstructions from upper treeline
- ecological impacts of drought

Reconstructed July-July precipitation
40
30
20
10
0
Use of the tree-ring
record to understand
structure of droughts
NE Utah reconstruction
1578-1579
1550 1560 1570 1580 1590 1600
We tend to celebrate
too early, and let a little
rain spoil our resolve

Bighorn Basin
(Upper Missouri)
Uinta Basin
(Upper Colorado)
Middle
Rio Grande

Bighorn River Basin
30% of Yellowstone R.
contribution to
Upper Missouri River
Gray, Jackson,
Fastie & Betancourt
(2004) J. Climate
Great
Drought
Late 16 th cent
Megadrought
Variability
dampened in
20 th century
Bighorn
Lake

Lake Powell Delta June 02 March 03
Uinta Basin
Great
Drought
Late 16 th
Century
Megadrought
20 th
Cent.
Gray, Jackson &
Betancourt (2004)
JAWRA

Sept 1951 Elephant Butte, NM Jan 2003
Reconstructed PDSI
Middle Rio Grande Basin, NM AD
Great
Drought
Late 16 th cent
Megadrought
Late 16 th cent
Megadrought
Grissino-Mayer, Baisan,
Morino, & Swetnam, 2001
Highly
variable
Large 20 Great
Drought
th cent. variability

Worst Case Scenarios for Water & Land Managers
Uinta Basin
(Upper Colorado)
AD 1226-2001
Gray, Jackson, &
Betancourt (2004)
Central Rio
Grande Basin
AD 622-1992
Grissino-Mayer,Baisan
& Swetnam (2001)
(1) 1250-1288
(2) 1437-1477
(3) 1772-1786
(4) 1566-1593
(5) 1625-1640
(1) 1571-1593
(2) 1272-1297
(3) 1945-1963
(4) 701-712
(5) 1131-1151

Best Case Scenarios for Water & Land Managers
Uinta Basin
(Upper Colorado)
AD 1226-2001
Gray, Jackson, Betancourt
& Eddy (2004)
Central Rio
Grande Basin
AD 622-1992
Grissino-Mayer,Baisan
& Swetnam (2001)
(1) 1594-1624
(2) 1837-1868
(3) 1965-1987
(4) 1478-1492
(5) 1330-1346
(1) 1553-1557
(2) 1627-1653
(3) 1978-1992
(4) 724-733
(5) 1377-1396

5,000,000
4,500,000
4,000,000
3,500,000
3,000,000
2,500,000
2,000,000
1,500,000
1,000,000
500,000
0
1860
Population Growth in Colorado
(Should this really be our reference period?)
3 rd 1965-1995 1965 1995
wettest period
in last 1000 yrs
Colorado population doubled
From 2 to 4 million
1880
1900
1920
1940
1960
1980
2000

LATITUDE
60
50
40
30
20
OLD (425) AND NEW (835) TREE-RING CHRONOLOGY
NETWORK FOR RECONSTRUCTING DROUGHT
OLD NETWORK
NEW NETWORK
CHRONOLOGIES
-140 -120 -100 -80 -60
LONGITUDE
Cook, Meko, Stahle, & Cleaveland (1999) J. Climate
1700-2000, http://www.ngdc.noaa.gov/paleo/
Krusik & Cook (2004) North American Drought Atlas;
last 2005 years

Western
U.S. grid
Krusik & Cook (2004) North American Drought Atlas; last 2005 years

1941
1941
Instrumental
Tree-Ring Tree Ring

1954
1954
Instrumental
Tree-Ring Tree Ring

Severe Droughts = Widespread Droughts
Cook, Meko, Stahle, & Cleaveland (1999)

1950’s 1950
1930’s 1930
In Cook et et al. al
gridded PDSI
reconstructions
1950’s-type
1950 type
droughts
6X more common
than 1930’s-type
1930 type
droughts

RWI
Period (Years)
2.0
1.5
1.0
0.5
2 4
8
16
32
64
128
256
512
Strong evidence for multidecadal (30-70 yr) persistence and
cross-regional synchrony
a. Climate Regions
Yellowstone Bighorn
Basin
Colorado
Plateau
d. Colorado Plateau
SW
Rockies
SE
Rockies
1400 1600 1800
0 0.003 0.04 0.15 0.49
2.0
1.5
1.0
0.5
2 4
8
16
32
64
128
256
512
2.0
1.5
1.0
0.5
2 4
8
16
32
64
128
256
512
b. Yellowstone
1400 1600 1800
0 0.016 0.06 0.24 0.98
e. SE Rocky Mountains
1400 1600 1800
0 0.006 0.05 0.15 0.45
Power (RWI) 2
2.0
1.5
1.0
0.5
2 4
8
16
32
64
128
256
512
2.0
1.5
1.0
0.5
2 4
8
16
32
64
128
256
512
c. Bighorn Basin
1400 1600 1800
0 0.077 0.28 1.1 1.9
f. SW Rocky Mountains
1400 1600 1800
0 0.057 0.18 0.39 0.80
Gray, Betancourt, Fastie, & Jackson (2003) GRL

What causes multidecadal
precip variability?
What controls the synchrony
across large basins?
Yellowstone Bighorn
Basin
Colorado
Plateau
SW
Rockies
SE
Rockies
Gray, Betancourt, Fastie,
& Jackson (2003) GRL
2.0
2.0
1.5
1.0 0.5
0.5
2.0
1.5
1.0
0.5
2.0
1.5
1.0
0.5
2.0
1.5
1.0
0.5
2.0
1.5
1.5
1.0
1.00.5
0.5
Yellowstone
Bighorn Basin
Colorado Plateau
SE Rocky Mountains
SW Rocky Mountains
1300 1400 1500 1600 1700 1800 1900

PDO reconstruction from SW USA/N Mexico tree rings
Biondi, Gershunov & Cayan (2001)

Tree-Ring Tree Ring Sites for AMO Reconstruction
SST anomaly
0.4
0.2
0
-0.2
-0.4
Instrumental
AMO
1850 1900 1950 2000
Gray, Graumlich,
Betancourt, & Pederson
In press GRL

Weak AMO
1550 1600 1650 1700 1750 1800 1850 1900 1950 2000
Gray, Graumlich, Betancourt & Pederson, in press GRL

PDO
AMO
Range 1-31 1 31 yrs
Average 6 yrs
Range 9-53 9 53 yrs
Average 23 yrs

20-yr 20 yr moving average of PDSI reconstructions
Vs. 20-yr 20 yr moving average of AMO 1567-1900 1567 1900

PCA of 20-yr 20 yr smoothed, reconstructed PDSI
1536-1967 1536 1967
=PDO =AMO =ENSO
Hidalgo (2004) WRR
WRR

Percentage of total power present at bidecadal and
multidecadal bands in gridded PDSI tree-ring reconstructions
Bidecadal band
(8-32 yrs)
Multidecadal
(32-64 yrs)
Hidalgo 2004
WRR
1525-1650 1525 to 1650 1700-1825 1700 to 1825 1700-1975
1850 to 1975
60%
50
40
30
20
10
0

Tree-ring regions
Gray, Graumlich, Betancourt
& Pederson, in prep
Wavelet analysis of AMO proxy

11-yr moving
departures
of annual PDO,
AMO & Colorado
River streamflow
at Lee’s Ferry
1661-1961
PDO departures
departures
McCabe, Hidalgo,
Gray & Betancourt in prep.
+PDO
-AMO AMO
-PDO PDO
-AMO AMO
AMO Departures
+PDO
+AMO
-PDO PDO
+AMO

Western
U.S. grid
Krusik & Cook (2004) North American Drought Atlas; last 2005 years

Percent Area of Drought
Western US Drought Area Index (-1 PDSI)
936 1034
1150 1253
Medieval Warm Period
80 yr lowpass
Little Ice Age
1829
1321 1613 1915
800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
Cook, Woodhouse, Eakin, Meko & Stahle (2004) Long-term
aridity changes in the Western United States. Science

Million Acre Feet
8
6
4
2
0
Combined Water Year totals for
Salt, Verde, Tonto & Gila Rivers
Medieval Warm
Period
2.5 maf
600 800 1000 1200 1400 1600 1800 2000
Graybill, Gregory, Funkhouser & NialsF. L. (in press)

Uniform heating
Larger
temperature
response in
the West
0 m
50
100
150
~20ºC
Warm, mixed
Surface layer
~20ºC
Deep, cold
ocean waters
Coupled interactions
(i.e. i.e. the the Bjerknes Bjerknes
feedback) feedback)
amplify the
East/west temperature
difference
Cooling by upwelling
opposes forcing in the
East, reducing
temperature response
Ocean dynamical ‘thermostat
thermostat’ (Clement et al. 1996)

Medieval Warm
Period
NH temperature
Palmyra
Coral
Little Ice Age
Wolfe Spörer Sp rer Maunder
Solar Irradiance
Volcanic activity
Cobb et al. (2003) Nature
Nature

Hypothesis: Atlantic & Pacific SST variations
also govern centennial-scale centennial scale trends
in western U.S. drought
Medieval Warm Period
AD 900-1300 900 1300
Cool
D
R
Y
Warm
Warm
Little Ice Age
AD 1400-1850 1400 1850
W
E
T
Cool

Standardized Units
3
2
1
0
-1
-2
-3
Natural precip. variability will modulate warming impacts
warm wet
dry cool
warm
/wet
cold
/dry
600 800 1000 1200
Salzer & Kipfmueller, in press
Temperature & Precipitation Reconstructions
from S Colorado Plateau
1400 1600 1800 2000

Ecological Role of Severe Drought
Significant Ecological Resetting Events

Longer, hotter growing seasons accelerate disturbance/
succession cycles and produce greater ecological synchrony
Disturbances
Broadscale
Mortality
Dry & Hot
Hydrologic
Effects??
Lots of
open niches
Increased
Synchrony
Accelerated
Regeneration
of Incumbent
Warm &
Wet
Invasion by
Native &
Non-native
Non native
Species

Demographic clocks are being reset by wildfires & dieoffs
Can we predict the outcomes of succession?
Courtesy of Neil Cobb

•El Niños impose short-lived breaks in even the most severe
droughts, testing the resolve of drought planners
•Climate variability is a spatially moving target; we should
generalize only from regionally integrated tree-ring records
•There appear to be inherent statistical relationships
between drought location, extent, duration & severity
•1950’s and 1999-2004 were 6X more common than 1930’stype
droughts in last 500 years
•1965-1995 one of wettest periods in last 1000 years
•AMO influenced frequency, persistence, extent &
multi-basin synchrony of drought & fire in last millennium
•AMO/PDO induces D2M fluctuations in water availability &
Ecosystems; complicated by warming trends
•Risk increases with time that extraction leases authorized
in periods of surplus will carry over into deficit periods