1. Earth System and Climate: Introduction (ESC-I) Coordinators: Dr. Vinu Valsala and Dr. Supriyo Chakraborty

2. Short introduction of instructor. Vinu K. Valsala (Vinu; E-mail: valsala@tropmet.res.in) PhD in Ocean and Atmospheric Sciences Research interests – – Climate, Variability and Global warming – – Oceanography – – Numerical Ocean Modeling – – Ocean Biogeochemistry

3. Contents of ESC-Intro. course: Earth System Science and Global Climate ChangeG Global Energy Balance P Global Carbon CycleC Recycling of Elements; C, N, O 2, O 3 depletionC Global Biogeochemical Cycle- oceansC/B Short-term Climate variability, Global Warming P/C/B Should be covered in 7-hours

4. Text books: Lee R. Kump, J. F. Kasting and R. G. Crane, 2010: The earth systems, Prentice-Hall Inc, pages-420 (*** Exams will be based on this; copies please make available in Library). A. E. Gill, 1980, Atmosphere and Ocean Dynamics, (Chapter-1 to 4), Int. Geo. Series, Vol.30. Sarmiento G. L., and N. Gruber, 2007, Ocean Biogeochemical Dynamics, Princeton. Univ. Press, pages- 530. IPCC-AR4, 2007, Climate Change, The Physical Science Basis, Chapter-2, Technical Summary. PDF copy available at http://www.ipcc.ch/publications_and_datahttp://www.ipcc.ch/publications_and_data

5. Other materials: Please prepare class notes by yourself. We will provide you our ppt slides (in a common server) No DICTATION of class notes (you are grown enough for this introductory course !) Assignments/Quiz, – – computer exercises of plotting the data, interpretations.

6. Examinations and evaluation TypeTimeMarks Mid-term exam2 nd month of the class 30% Final-term4 th month of the class 50% Assignments/QuizTwo/Three times 20% Total100%

7. Let’s Start!

8. C 10 -7 10 0 10 2 10 3 10 5 ν 10 7 10 μmeter km galactic ν μ minutes hours days years k-years galactic Daily life Sunny /Rain Planets, Moon, stars An year/ 1000 km Climate Earth system and climate:- A space-time perspective Life-zone k-km Weather: day-to-day states of the Atmosphere (environment) Climate: A long term average of the states of the atmosphere.

9. Terminologies to remember: Geometry of earth Latitude; 90s~90n Longitude; 180w~180e or 0 0 ~ 360 0 Equator = 0 0 EastWest North pole South pole

10. Some useful quantities to remember Shape of the earth: Oblate spheroid Image courtesy : Wikipedea Radius of the earth: 6371 Km (6378.14 - 6356.8) Mass of the earth: 5.977x10 24 Kg Average density = 5517 kg/m3 Rotation speed = 0.729x10 -4 rad/sec Average surface temperature = 288K, (15 0 C)

11. Regional characterizations: Tropics Sub-tropics Mid-latitude Polar Tropical climate Temperate Climate Polar Climate

12. Weather and Climate. 01-Augst to 08-August temperatures over a Particular location  Weather Weather represents day-to-day variations in our atmosphere Climate is a long term average of weather (100-years, 1000-years, 50years, 30 years)

13. Major three themes that we address in this course is. The earth system itself, as a combination of Biota, Atmosphere, Hydrosphere and Solid Earth. What causes current global climate change Climate is changing ever since the earth is formed 4.6 billion years ago. There are episodic ice-ages and interglacial warm periods. So, if the current climate is not warmed by humans, are we going back to ice-ages?

14. Schematics of earth system Schematics showing interactions between various Components of Earth system.

15. Global Climate change. Evidences of global change on short time scales.

16. Global average observed surface temperature trend From IPCC Assessment Report 4 (AR-4), 2007

17. What causes in global temperature change in last 100 or 200 years? Are they part of any natural change? Are they induced by humans (Anthropogenic?) Anthropogenic causes of climate change Fossil fuel burning Deforestation Ozone layer depletion What are the natural reasons for climate change?

18. The Green house effect. Earth Sun Short wave Long wave (heat) GH-effect helps the surface Temperature to be warm at 15 0 C = CO2 and Other GH-gases

19. The status of present day green house gases and radiation budget. Gas17651992Current rate of increase (% per year) Pre- industrial Anthr opoge nic CO 2 2783560.4501.4 CH 4 0.71.710.61.10.48 CFC-110.00.0002680.0 0.07 N2ON2O0.2750.310.251.250.15 Concentration (ppm)Radiative forcing (w/m2) Sarmiento and Gruber, 2007, Ocean BGC Dyn.,

20. Radiative forcing per additional molecule relative to the radiative forcing due to one additional molecule of CO 2. GasRelative Forcing CO 2 1 CH 4 21 N2ON2O206 CFC-1112,400 Addition of CH 4 has more impact than addition of CO 2. Addition of N 2 O has more impact than addition of CH 4

21. Present day CO 2 ; Keeling curve. © http://en.wikipedia.org/wiki/File:Mauna_Loa_Carbon_Dioxide- en.svg

22. Atmospheric CO2 from 1700 to 2010

23. But ~50% of man-made CO2 is absorbed by oceans and land. 50 % 20 % 30 % Oceans sink ~30% of anthropogenic CO2 Terrestrial ecosystem absorbs ~ 20% of anthropogenic CO2.

24. Annual mean CO2 sinks and sources by terrestrial biospheres (~2 PgC/yr) CarbonTracker data from ESRL, NOAA, USA.

25. Annual mean CO2 sinks and sources by the ocean (~2PgC/yr) Shamil et al., 2012, Atm. Chm. Phy. Discussions

26. 1990200020101980 10 15 Gram Carbon/year CO2 exchange between ocean & atmosphere, data developed at NIES, Japan. Valsala et al., 2010, Tellus-B, - 1.5x10 15 gC/yr

27. Global warming or Global Cooling ? IPCC-AR4 report, 2007 Schematic

28. Human impacts on famines and mass deaths…(Ethiopian famine) Normal 1984-85 Ethiopia

29. Long term climate change: by Natural causes (observed- for 1 million years) 0 100-k300-k500-k700-k Kilo-years CO2 Petit et al, 1999, Nature T-Proxy

30. Higher CO2 leads to Higher temperatures Lower CO2 leads to lower temperature But what causes variations in CO2 ? Earth system as a self-regulatory system.

31. What are the natural causes of long term climate change? Milankovitch cycles (periodic) Precision  19-23 k-yrs Tilt  41-42 k-yrs Eccentricity  100-400 k-yrs

32. What are other natural causes of radiation budget change? (aperiodic) 0 50 100 150 200 250 300 350 400 Millions of years ago Devonian Carboniferous Permian Triassic Jurassic Cretaceous Quaternary 0 15 30 45 60 Quaternary Miocene Oligocene Eocene Paleocene 1 2 4 6 8 Pleistocene Miocene Pliocene Continental drifts Climate Human evolution = eradication of life; Are we driving next eradication? Tertiary