Earth’s ClimatePast and Future

Prof. Z. LiuDept. Atmospheric and Oceanic Sciences

Text BookEarth’s Climate, Past and Future, W.F. Ruddiman2nd edition, W.H. Freeman and Company

Reading MaterialIPCC AR5: Chapter 5: Information from paleoclimate archives

GradingQuiz: 1/3Presentation: 1/3Term paper: 1/3

Syllabus for AOS528

Part I: Basics of the Climate SystemLecture 1: Introduction: Overview of the climate system (Ch.1)Lecture 2: Climate Archives and Data (Ch.2)Lecture 3: Climate Modeling (Ch.2)

Part II: Tectonic-Scale Climate ChangeLecture 4: CO2 and long term climate: last 4.5 Byr (Ch.3)Lecture 5: Plate tectonics and climate: last 550 Myr (Ch.4)Lecture 6: The greenhouse earth (Ch.5)Lecture 7: Back into the icehouse: last 55 Myr (Ch.6)Quiz 1

Part III: Orbital-Scale Climate ChangeLecture 8: Orbital variations and Insolation Change (Ch.7)Lecture 9: Orbital control of Monsoon change (Ch.8)Lecture 10: Orbital control of Ice sheets (Ch.9)Lecture 11: Glacial cycles and greenhouse gases (Ch.10)Lecture 12: Carbon pumping into the deep ocean (Ch.10)Lecture 13: Orbital-scale interactions (Ch.11)Quiz 2

Part IV: Deglacial and Millennial Climate ChangesLecture 14: The Last Glacial Maximum (Ch.12)Lecture 15: The last deglaciation (Ch.13)Lecture 16: Climate changes in the last 10,000 years (Ch.13)Lecture 17: Millennial changes (Ch.14)Quiz 3

Part V: Historical Climate ChangesLecture 18: The Little Ice Age (Ch.15)Lecture 19: El Nino, La Nina and Southern Oscillation (Ch.15) Lecture 20: Impacts of climate on early humans and civilizations (Ch.16)Lecture 21: Anthropogenic inputs of gases (Ch.16)

Part VI: Future Climate ChangesLecture 22: The greenhouse debate (Ch.17)Lecture 23: Climate change in the future 100-1000 years (Ch.18)

Student presentations: IPCC paleo chapter

Lecture 1: Overview of the Climate System

(Chapter 1)

Global warming?

1.Continetnal warming,even some cooling, 2. surface moreWhy?

Global Temp Trend

Less coherent change,Why dryer? Caution: 50-present only!

Global Prep Trend(?)

Melting Lake Ice !

Lake

Mendota

Local Climate Change

Global Warming?!

Different Time Scales in the Past

Different Time Scales in the Past

Atmospheric CO2 Evolution

Tectonic Impact

Abrupt Changes

The Cold Climate

The Dry Climate

ModernModern

LGMLGM

Deep Ocean Changes

Fig. 1. Paleoclimate time series spanning the last deglaciation and Holocene. From left to right, June insolation at 60ºN (Berger, 1978). Far field relative sea level records (Fleming et al., 1998; Clark et al., 2009b) (black squares) and Laurentide Ice Sheet volume (Carlson, 2008; Clark, 2009c). Antarctic Dome C CO2 (Monnin et al., 2001). Antarctic Dome C dD (EPICA, 2004). Greenland GISP2 d18O (Grootes et al., 1993). Hulu (black) and Dongge (gray) Caves speleothem d18O (Wang et al., 2001; 2005). West African terrigenous dust (deMenocal et al., 2000). ENSO frequency (Moy et al., 2002). Tropical sea surface temperatures (SST): dark blue eastern equatorial Pacific (Lea et al., 2006); blue Cariaco Basin (Lea et al., 2003); Red western equatorial Pacific (Stott et al., 2007). Bars denote events discussed in text.

Last 21,000 years

Complex System and Interactions

Earth System ModelEarth System Model

Climate Model for Prediction and Mechanism

Climate Model and Climate Projection

IPCC, 2007IPCC, 2007

Decadal (10-30-yr) Decadal (10-30-yr) PredictionPrediction

Test Climate Model Against the Past Obs

21 ka – 0ka

Test Climate Model Against Past Obs

Fig.3: Observation of d13C (left), and model Atlantic salinity (zonal mean) (middle) and the AMOC overturning streamfunction (in Sv.) (right) at 0ka (upper) and LGM (lower). Model salinity compares well with the d13C reconstruction in the deep ocean, with a 1-km shallowing of the NADW and AMOC.

Proxy CCSM3

Δ 13C

0ka

21ka

Salinity AMOC

Otto-Bliesner et al., 2007, GRL

0ka

21ka

CCSM HadCM

MIROC

ECBILT_CLIO

Δ 13C

AMOC in Models (PMIP2) Observation

Fig.2: Data-model comparison for benchmark time series. (a) June insolation at 60 N (red) and atmospheric CO2 concentration. (b) Sea level from the reconstruction (triangle) and model (equivalent sea level for meltwater). (c) Meltwater fluxes in the model. (d) Pa/Th ratio at Bermuda as a proxy for AMOC strength, and model AMOC transport at 30oS. (e) GISP2 annual surface air temperature in (d18O) reconstruction and model. (f) Vostok annual surface air temperature in (d18O) reconstruction (ref) and model. (g) Annual SST in Iberian Margin in reconstruction and model. (h) Annual SST in Cariaco basin in reconstruction and model. (i) Annual rainfall in Cariaco Basin in reconstruction and model. In (c-i), reconstruction is in grey, and model simulations are in color (red for DGL-A , blue for DGL-B.). (see Liu et al., 2009 for more details).

Climate Variability Climate Variability Tropical Pacific SST

El Nino

1935 Texas (Dustbowl)1935 Texas (Dustbowl)

1997 Kansas1997 Kansas

Climate Change and Climate VariabilityClimate Change and Climate Variability

IPCC, 2007IPCC, 2007

July

Giannini et al., 2003: Science

Sahel Rainfall

Human effect (trend) or/and variability?

Charney???Charney

Climate Change: Global to Regional

Global US

Wisconsin Madison

Wisconsin Climate Change

Temp

Z. Liu

NAO

and North Atlantic Oscillation

?

http://www.aos.wisc.edu/~sco/divisions/WI-00-temp-djf.gif

Winter

Summer

Wisconsin Temperature: Seasonal

Annual

Dust Bowl

Climate Projection and Decadal Prediction

IPCC, 2007IPCC, 2007

Decadal (10-30-yr) Decadal (10-30-yr) PredictionPrediction

End of Lecture 1