Fear and loathing in Earth System Science

1. Fear and loathing in Earth System Science

2. Earth System Science Geol 206.3 Instructors Dr. William P. Patterson Office: 214 Geology Phone: 306-966-5691 http://geochemistry.usask.ca/bill.html and Dr. Chris Holmden Office: 242 Geology Phone: 306-966-5697 http://geochemistry.usask.ca/sasklab/ holmdenresearch.html

3. Global Change • Climate is changing • Climate has changed in the past • Climate will change in the future • How will this affect you?

4. The Earth System- consists of four components Atmosphere- thin envelope of air that surrounds the Earth. Hydrosphere- water (oceans, lakes, rivers, groundwater and ice). Biosphere- all living things. Solid Earth or Lithosphere- rocks, including unconsolidated sediment. Primarily the solid earth consists of three components, the core, mantle, and crust. In this course you will learn how all of these components interact with each other.

5. Global Change Key questions related to Earth System Science What is meant by a systems approach? How does global warming differ from the greenhouse effect, and is global warming actually occurring today? What is the Antarctic ozone hole, and what is its significance? Should we be concerned about tropical deforestation? What can understanding Earth’s past tell us about Earth’s future?

6. Introduction The Earth has changed constantly since the beginning of Earth time (4.6Ga). Probably true However, at the present time things are changing at a rate that may be as high or higher than at any other time. Probably not true…but sounds good/scary Anthropogenic- human induced, literally “of human origin” (e.g. pollution, deforestation, extinction, domestication of plants and animals…i.e. farming).

7. Global Change Key questions What is meant by a systems approach? We will view the Earth as a system of interrelated and interacting components. Examples of systems-- stereos, cars, weasels

8. Global Change Key questions How does global warming differ from the greenhouse effect, and is global warming actually occurring today? Global warming-a warming of Earth’s atmosphere that is due to an anthropogenic enhancement of the greenhouse effect. Greenhouse effect-gases absorb outgoing infrared radiation (IR or radiant heat) and reradiate it back to the Earth’s surface. So…is global warming happening today? Well…maybe…sorta…probably?

9. The Greenhouse Effect is a completely natural process that operates on all planets with atmospheres. Important greenhouse gases on Earth include Carbon dioxide- enters the atmosphere from natural and anthropogenic sources. Methane- likewise has both natural and anthropogenic sources. Water vapor- the most important greenhouse gas of all.

10. Global Change Key questions What is the Antarctic ozone hole, and what is its significance? The Antarctic ozone hole is an area of extremely low ozone concentration the ozone layer. The ozone layer protects the Earth’s surface from receiving dangerous amounts of the Sun’s ultraviolet radiation.

11. Global Change Key questions Should we be concerned about tropical deforestation? Think of the biodiversity in this environment

12. Pan-American Highway just north/west of the Columbian border

13. After Lachniet and Patterson, 2002

14. Current clear-cutting next to the highway

15. Most areas are used for lumber first, then cattle, fruit trees, and coffee

16. Southern Panama- deforested for cattle Think of the biodiversity in this environment

17. Later on in this course, we will look at geologic records of the effect of deforestation on climate change.

18. Global Change Key questions What can understanding Earth’s past tell us about Earth’s future? A lot!

19. In order to make intelligent decisions regarding global change, we have to understand how the Earth’s climate system works today. However, the climate system is exceptionally complicated and has changed consistently throughout Earth history. In order to predict how climate will change in the future, we need to look at past climates before humans were capable of changing the atmosphere in significant ways. We are currently nearing the end of an Interglacial period. Until recently people were very concerned about this warm period ending and the return of the ice age.

20. We can use sediment cores as a record of climate change.

21. In the 1950s scientists noticed that the stable isotope record recovered from deep sea cores showed distinct increases and decreases that seemed to correspond to glacial records on land.

22. Cesere Emiliani at the University of Chicago

23. Initially the isotope fluctuations were thought to represent changing temperature. Later it was realized that the ups and downs recorded the expansion and contraction of the ice sheets. Later in this course we will examine the long-term record of climate from these records.

24. One of our areas of interest is the development of very high resolution records from continental sites such as the one below. Cross-section of modern marl bench at Lough Inis Ui Chuinn near Cora finne, Eire Core #2 6/03 Core #1 7/02

25. Onshore coring July 2000 & June 2003 Cnoc mhuire, Contae Maigh Eo, Eire

26. Offshore coring June 2003 Lough Inis Ui Chuinn

27. Preliminary research- Central New York

28. Dry JJA Humid JJA

29. The Younger Dryas is perhaps the most dramatic climate change episode since the last deglaciation. It shows up clearly in the Finger Lakes region permitting us to recreate atmospheric circulation. Our continuous isotope record has yielded a continuous Holocene circulation record for eastern North America. From Kirby, Patterson, Mullins, and Burnett, Climate Dynamics, 2002

30. Global change on short time scales Evidence for global warming- global warming is perhaps the most important and at the same time controversial issue that faces humans today. Why is this issue so important? Climate affects everything on Earth, both living and non-living. Not everyone believes that global warming has started yet. What is the evidence for and against global warming?

32. What do we know to be true?

40. Observed changes in surface temperature We are certain that greenhouse gases are increasing in the atmosphere. Is this leading to an increase in temperature? Maybe? Recording stations (meteorological stations) show consistent increases in temperature. But… Meteorological stations are generally located in the places where people live…more and more people live near the stations all the time. This generates a “heat island” that influences the temperature records. Scientists try to account for the heat island effect. Boats that record water temperatures also introduce errors into the record by changing the way that temperatures are recorded.

41. More problems with the temperature change being related to greenhouse gases. We have just come out of a particularly cold period called the “Little Ice Age”, perhaps climate is merely recovering? The period between the 1940s and 1970s was cold? This may have been caused by sulfate aerosols that enter the atmosphere from coal fired power plants. We now scrub the SO2 from coal plant emissions to protect lakes and rivers from acid rain possibly leading to an increase in warming?!

42. 20th century cooling? Humans tend to focus on the most recent events Geologists provide a long-term “memory” needed to evaluate environmental change in a meaningful way

44. Consequences of global warming

45. Consequences of global warming

47. Consequences of global warming

48. Consequences of global warming

49. Consequences of global warming Loss of biodiversity/mass extinction- it takes a very long time to recover from a mass extinction. Global changes on long (geologic) time scales For an explanation and brief description of the geological time scale you may want to look at the following website http://www.ucmp.berkeley.edu/help/timeform.html