Earth’s Climate Past and Future Prof. Z. Liu Dept. Atmospheric and Oceanic Sciences

weekdatetopics 1Sept. 2, 4 2Sept.9, 11Travel 3Sept.16,18 4Sept.23,25Travel? 5Sept. 30, Oct., 2Travel (quiz) 6Oct., 7, 9 7Oct. 14, 16(?)Travel (quiz) 8Oct 21, 23 9Oct 28, 30 10Nov.4, 6 11Nov.11, 13 12Nov.18, 20 13Nov.25, 27 Thanksgiving 14Dec. 2, 4 15Dec. 9, 11 16Dec. 16, 18AGU

Text Book Earth’s Climate, Past and Future, W.F. Ruddiman 2 nd edition, W.H. Freeman and Company Reading Material IPCC AR5: Chapter 5: Information from paleoclimate archives Grading Quiz: 1/3 Presentation: 1/3 Term paper: 1/3

Syllabus for AOS528 Part I: Basics of the Climate System Lecture 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 Change Lecture 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 Change Lecture 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 Changes Lecture 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 Changes Lecture 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 Changes Lecture 22: The greenhouse debate (Ch.17) Lecture 23: Climate change in the future 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 more Why? 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

Atmospheric CO2 Evolution

Tectonic Impact

Abrupt Changes

The Cold Climate

The Dry Climate

Modern LGM 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 Model Climate Model for Prediction and Mechanism

Climate Model and Climate Projection IPCC, 2007 Decadal (10-30-yr) Prediction

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 CCSMHadC M MIRO C ECBILT_CLIOΔ 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 Tropical Pacific SST

El Nino

1935 Texas (Dustbowl) 1997 Kansas

Climate Change and Climate Variability IPCC, 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 ?

Winter Summer Wisconsin Temperature: Seasonal Annual Dust Bowl

Climate Projection and Decadal Prediction IPCC, 2007 Decadal (10-30-yr) Prediction

End of Lecture 1