Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible...
-
Upload
juliet-elliott -
Category
Documents
-
view
225 -
download
4
Transcript of Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible...
![Page 1: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/1.jpg)
Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly”
and Plausible Dynamical Origins
Michael E. Mann Penn State University
with contributions from: Caspar Ammann, Raymond Bradley, Elizabeth
Crespin, Jeff Donnelly, Greg Falugevi, Fangxing Fan, Hugues Goosse, Malcolm Hughes, Klaus Keller,
Scott Rutherford, Drew Shindell, Axel Timmermann, Jonathan Woodruff, Zhihua Zhang
1th International Meeting on Statistical ClimatologyUniversity of Edinburgh, Scotland
July 13, 2010
![Page 2: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/2.jpg)
Global Surface Temperature Changes
![Page 3: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/3.jpg)
Climate “Proxy” Data…
Global Surface Temperature Changes
![Page 4: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/4.jpg)
Climate “Proxy” Data…
Reconstructions of Past Climate
![Page 5: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/5.jpg)
Climate Change 2001: The Scientific Basis, Houghton,
J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001
Surface Temperature Reconstructions
![Page 6: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/6.jpg)
Surface Temperature Reconstructions
![Page 7: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/7.jpg)
Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002, doi:10.1029/2003RG000143, 2004.
Surface Temperature Reconstructions
![Page 8: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/8.jpg)
European Winter Cooling During the Little Ice Age
![Page 9: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/9.jpg)
El Nino
Sources of Uncertainty
![Page 10: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/10.jpg)
Sources of Uncertainty
El Nino
![Page 11: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/11.jpg)
Combined response to Solar +Volcanic Forcing
Ensemble mean Nino3 (100 realizations of CZ model)
40 year smooth
Palymra coral isotopes (standardized to have same mean and standard deviation as Nino3 composite series)
Mann, M.E., Cane, M.A., Zebiak, S.E., Clement, A., Volcanic and Solar Forcing of The Tropical Pacific Over the Past 1000 Years, Journal of Climate, 18, 447-456, 2005.
How did Natural Forcings Influence influence ENSO and the Tropical Pacific During the Past Millennium?
![Page 12: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/12.jpg)
simulation
smoothed simulation result
Coral isotope reconstruction of past El Nino variations
Combined response to Solar +Volcanic Forcing
‘Little Ice Age’ wet in Kenya: El Nino-like conditions
How did Natural Forcings Influence influence ENSO and the Tropical Pacific During the Past Millennium?
![Page 13: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/13.jpg)
Cook et al, Science, ‘04
simulation
smoothed simulation result
Coral isotope reconstruction of past El Nino variations
Combined response to Solar +Volcanic Forcing
‘Little Ice Age’ wet in southwestern U.S.:
El Nino-like conditions
How did Natural Forcings Influence influence ENSO and the Tropical Pacific During the Past Millennium?
![Page 14: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/14.jpg)
Cook et al, Science, ‘04
simulation
smoothed simulation result
Coral isotope reconstruction of past El Nino variations
Combined response to Solar +Volcanic Forcing
‘Medieval Warm Period’ dry in southwestern U.S.:
La Nina-like conditions
How did Natural Forcings Influence influence ENSO and the Tropical Pacific During the Past Millennium?
![Page 15: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/15.jpg)
Surface Temperature Reconstructions
![Page 16: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/16.jpg)
Surface Temperature Reconstructions
Science (11/27/09)
![Page 17: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/17.jpg)
Regional Time Series
Surface Temperature Reconstructions
![Page 18: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/18.jpg)
statistical model
historical record
Model resolves ~50% annual variance in both calibration and split calibration/validation over 1870-2006
Applications: Atlantic Tropical Cyclones
![Page 19: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/19.jpg)
statistical model
historical record
Model resolves ~50% annual variance in both calibration and split calibration/validation over 1870-2006
Applications: Atlantic Tropical Cyclones
![Page 20: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/20.jpg)
sediments
historical record
95% uncertainties
95% uncertainties
Statistical model
Applications: Atlantic Tropical Cyclones
![Page 21: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/21.jpg)
Surface Temperature Reconstructions
Science (11/27/09)
![Page 22: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/22.jpg)
Surface Temperature Reconstructions
Science (11/27/09)
![Page 23: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/23.jpg)
Model-Data Comparisons
Positive Phase of Northern Annual Mode
Science (11/27/09)
![Page 24: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/24.jpg)
Past Natural Arctic warming
PROXIES MODEL
Paleoclimate Data Assimilation
![Page 25: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/25.jpg)
Paleoclimate Data Assimilation
SAT
Z(800mb)
PROXIES MODEL
Past Natural Arctic warming
![Page 26: Global Signatures of the “Little Ice Age” and “Medieval Climate Anomaly” and Plausible Dynamical Origins Michael E. Mann Penn State University with contributions.](https://reader033.fdocuments.us/reader033/viewer/2022052510/56649e395503460f94b2b015/html5/thumbnails/26.jpg)
CONCLUSIONS
•Reconstructed La Nina-like pattern during Medieval times, and El Nino-like anomalies during the “Little Ice Age”, suggest a ‘thermostat’ response response to natural radiative forcing
•Recent hemispheric-scale warmth anomalous in at least a millennial context; can only be explained by anthropogenic radiative forcing
•Prior to the 20th century, warmth and cold was highly regionally variable
•Combination of warm tropical Atlantic and La Nina-like conditions in the tropical Pacific can explain periods of relatively high past Atlantic Hurricane activity
•Medieval warmth in high-latitude North Atlantic and parts of North America rivaled modern warmth
•Response of Northern Annular Mode/NAO to natural volcanic and solar radiative forcing appears to explain enhanced ‘Little Ice Age’ and ‘Medieval Warm Period’ temperature signal in regions such as Europe