1. GAIA: The Earth System James Kasting Professor of Geosciences 443 Deike

2. Gaia—The Greek goddess Gaia is Mother Earth. She is from whom everything comes, but she is not quite a divinity, because she is Earth. She bore the Titans as well as monsters like the hundred armed men, and some of the Cyclopes - others were sons of Poseidon. She was the daughter of Chaos, and the mother of all creatures (according to some). She was the first and the last, and wanted all of her children, no matter what. She was primarily spoken of as a Mother of other Gods, rather than having her own myths. http://www.paleothea.com/Majors.html

3. First presented in the 1970s by James Lovelock http://www.ecolo.org/lovelock 1979 1988 The Gaia Hypothesis

4. The Gaia Hypothesis: First presented in the 1970s by James Lovelock Lynn Margulis was an early supporter, also married briefly to Carl Sagan, and she pointed out the importance of microbial life --Lynn passed away in 2011

5. Latest updates to Gaia 20062009 Lovelock warns that humans are endangering the planet and that Gaia will get her revenge…

6. The Medea and Rare Earth Hypotheses Peter Ward Medea hypothesis: Life is harmful to the Earth! Rare Earth hypothesis: Complex life (animals, including humans) is rare in the universe 20092000

7. The latest addition to this literature Your professor: James Kasting My not-so-new book (not your textbook!) (Princeton University Press, 2010) As you will see, I am more optimistic than either Peter Ward or Jim Lovelock

8. The Gaia Hypothesis: 1)Earth is a self-regulating system 2)The system includes both life and the physical world 3)The system is capable of maintaining a surface environment that is suitable for life

9. Gaia analogy Redwood trees are like Gaia because 97% of their tissues are dead. The wood of the trunk and the bark of the tree are dead. Only a small rim of cells along the periphery of the trunk is living. The trunk of the tree is similar to the Earth's lithosphere with a thin layer of living organisms spread across its surface. The bark, like the atmosphere, protects the living tissues, and allows for the exchange of biologically important gases, such as carbon dioxide and oxygen. http://www.oceansonline.com/gaiaho.htm

10. Scientific Implications of Gaia Hypothesis: A new view of the Earth as one system Not really that new—the Russian geochemist Vladimir Vernadsky had proposed this back in the early part of the last century From this view emerged Earth System Science

11. Earth System Science: The study of the relationships among system components, and the influence of many processes (including life) on the evolution of the global environment. http://www.earthsystemschool.mpg.de/web/imprs_profile.jpg

12. But, this is all pretty philosophical. We’ll also be interested in more immediate and practical questions, especially the topic of human-induced global warming To get us thinking about this, let’s consider what has happened the past few summers…

13. Wild US summer heat wave smashes records By chillymanjarochillymanjaro – July 31, 2011 http://thewatchers.adorraeli.com/2011/07/31/wild-us-summer- heat-wave-smashes-records/ Graph shows high daily temperature on July 12, 2011 1479 daily U.S. temperature records were broken in the month of July

14. http://www.businessinsider.com/texas-drought-2011-08 In addition, the state of Texas was hit with its worst drought ever Although there is no assurance that this drought has been self-induced, --indeed, it is blamed mostly on La Niña--this is precisely the kind of thing that is predicted to happen as the global climate warms

15. Extreme heat events In summer, 2012, over 60% of the contiguous 48 states were experiencing moderate to severe drought July, 2012, was the hottest single month ever recorded in the continental U.S. Is this evidence of global warming, or is this simply an unusual climate event? See the animated drought map at: http://www.cnn.com/interactive/ 2012/07/us/drought/index.html http://www.cpc.ncep.noaa.gov/products/ex pert_assessment/seasonal_drought.html

16. California drought: 2012-2015 California has been experiencing severe drought for the last three years Lake Shasta (at right) in northern California is currently (summer, 2014) at 37% of capacity Is this drought, too, a result of La Niña? Alternatively, is it simply random or, more worrisomely, could it be a harbinger of anthropogenic global warming? http://ca.water.usgs.gov/data/drought/

17. Alaska Heat Wave (May, 2015) Temperatures near Eagle, Alaska, reached 91 o F on May 23, 2015 The entire third week of May saw temperatures of 80 o F or more http://ecowatch.com/2015/06/05/heat-wave-alaska/

18. Alaska Heat Wave (May, 2015) Alaska as a whole was 10-12 o C (18-22 o F) warmer than usual during the third week in May The western continental U.S. was much colder than usual during this period http://ecowatch.com/2015/06/05/heat-wave-alaska/