Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist...
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Transcript of Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist...
![Page 1: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/1.jpg)
Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling
Dr. Craig LoehleNCASI Principal Scientist
552 S Washington St., Ste. 224Naperville, Illinois 60540
![Page 2: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/2.jpg)
The Broken Hockey Stick
• Fundamental assumptions of tree ring reconstruction are untested
• In fact, they are violated• Ms published online in Climatic Change,
Sept. 08• “A Mathematical Analysis of the Divergence
Problem in Dendroclimatology”
![Page 3: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/3.jpg)
Climate Reconstruction(based largely on tree ring data)
![Page 4: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/4.jpg)
How is it Done?
• Assume linear model ring vs. temperature• Fit to temperature histories, 20th Century• Inverse function for past temperature from
ring width / density
![Page 5: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/5.jpg)
Signs of Trouble
• Widespread observations of divergence– good fit up to 1960– more warming than predicted by tree rings after
1960– Explanations are speculative
• Individual trees– may not respond to temperature– may grow worse when warmer
• (PPT limits)
![Page 6: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/6.jpg)
IF Linear Response, Perfect Fit
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
0 200 400 600 800 1000
Years
Tem
pera
ture
0.00
0.10
0.20
0.30
0.40
0 200 400 600 800 1000
Years
Rin
g W
idth
![Page 7: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/7.jpg)
IF Nonlinear Response, Get Truncation (inversion)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
-2 0 2 4
Temperature
Rin
g W
idth
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
0 200 400 600 800 1000
Years
Tem
pera
ture
Peaks become troughs!
![Page 8: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/8.jpg)
IF Ramp Response (no PPT Limitation),Get Truncation
0.20
0.25
0.30
0.0 0.5 1.0 1.5 2.0
Temperature
Rin
g W
idth
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
0 200 400 600 800 1000
Years
Tem
pera
ture
Ramp results from species maximum growth rate
![Page 9: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/9.jpg)
Conclusions
• Linear growth response invalid• Nonlinear growth explains divergence• Consequence
– can’t guarantee detection of temperatures warmer than calibration period
• Flattens out timeseries; reduces mean, range, and maximum• Can’t evaluate MWP or how unusual recent decades are from
linear reconstructions• Can’t use nonlinear model because gives nonunique inverse
model
![Page 10: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/10.jpg)
The 1500-Year Climate Cycle
• Dansgaard-Oschger events in ice core data• About 1500 years apart• Cause: solar or ocean oscillator (multi-state
system)• Did they continue?
![Page 11: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/11.jpg)
Greenland Data AnalysisUpdated GICC05 ice core chronology
Years BP (Yr 0 = 2000 AD)
δ18O
![Page 12: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/12.jpg)
Greenland Data AnalysisBest-fit model for 30,000 to 37,000 BP
(R2 = 0.36, period = 1486 yrs)
Years BP (Yr 0 = 2000 AD)
δ18O
(val
ues
cent
ered
for b
etter
esti
mati
on o
f cyc
les)
![Page 13: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/13.jpg)
Greenland Data AnalysisBest-fit model for 40,000 to 46,000 BP
(R2 = 0.30, period = 1598 yrs)
Years BP (Yr 0 = 2000 AD)
δ18O
(val
ues
cent
ered
for b
etter
esti
mati
on o
f cyc
les)
![Page 14: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/14.jpg)
Greenland Data AnalysisBest-fit model for the Holocene to 8000 BP
(R2 = 0.45, period = 1434 yrs)
Years BP (Yr 0 = 2000 AD)
δ18O
(val
ues
cent
ered
for b
etter
esti
mati
on o
f cyc
les)
![Page 15: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/15.jpg)
Best-fit Model 1681- and 1470-Year CyclesCompared to Loehle Reconstruction (R2 = 0.68, 0.65 respectively)
(confidence intervals not shown)
Years BP (Yr 0 = 2000 AD)
Anom
aly
(°C)
1470-yr cycle
1681-yrcycle
![Page 16: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/16.jpg)
Best-fit Model to Moberg Low-Frequency Data (1152-yr cycle, R2 = 0.69)
and Fit to 1470-yr cycle (R2 = 0.54)(confidence intervals not shown)
Years BP (Yr 0 = 2000 AD)
Anom
aly
(°C)
1470-yr cycle1152-yr cycle
![Page 17: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/17.jpg)
Best-fit Model to North Iceland Sea Surface Temperature(1552-yr cycle, R2 = 0.20)
Data shown after linear cooling trend removal
Years BP (Yr 0 = 2000 AD)
Anom
aly
(°C)
![Page 18: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/18.jpg)
Oxygen Isotope Data from Central Alps, past 9000 yrsBest-fit models for 2004 AD to 3500 BP and 6500 BP to 8996 BP
(1479-yr cycle, R2 = 0.27, peak-to-trough amplitude 0.33°C)
Years BP (Yr 0 = 2000 AD)
-del
ta O
-18
(%)
![Page 19: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/19.jpg)
Temperature inferred from Japanese CedarBest-free-form-fit (1089-yr cycle, R2 = 0.28); Best-fit when
forced with 1470-yr cycle looks similar (R2 = 0.22)
Years BP (Yr 0 = 2000 AD)
Anom
aly
(°C)
1089-yr cycle
1470-yr cycle
![Page 20: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/20.jpg)
Conclusions
• Mean period 1524 yr vs. 1470 yr hypothetical (3.7% off)
• Models, data strongly agree on timing of MWP, LIA
• Supports role for this cycle in recent warming
![Page 21: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/21.jpg)
Ocean Temperatures:Recent Trends
• ARGOS float data• To 700 m depth• 4.5 years data• Global coverage
![Page 22: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/22.jpg)
Ocean heat content
Calendar Year
Oce
an H
eat C
onte
nt (x
1022
J)
![Page 23: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/23.jpg)
Ocean heat content smoothed with a 1-2-1 filterand overlaid with a best-fit linear plus sinusoidal
(seasonal) model (R2 = 0.85)
Calendar Year
Oce
an H
eat C
onte
nt (x
1022
J)
![Page 24: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/24.jpg)
Ocean heat content smoothed with a 1-2-1 filterand overlaid with linear trend portion of best-fit
model (slope = -0.35 x 1022 J/yr)
Calendar Year
Oce
an H
eat C
onte
nt (x
1022
J)
![Page 25: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/25.jpg)
Recent Temperature Downturn Evident in Hadley Data
![Page 26: Broken Hockey Sticks, 1500 Year Cycles, and Ocean Cooling Dr. Craig Loehle NCASI Principal Scientist 552 S Washington St., Ste. 224 Naperville, Illinois.](https://reader035.fdocuments.us/reader035/viewer/2022070413/5697bfea1a28abf838cb72c9/html5/thumbnails/26.jpg)
Conclusions
• Cooling trend over past 4.5 years matches satellite, surface data
• Rate of cooling similar to rate of warming before 2003