BIOL 4120: Principles of Ecology Lecture 21: Human Ecology Global Climate Change

1. BIOL 4120: Principles of Ecology Lecture 21: Human Ecology(Global Climate Change) Dafeng Hui Room: Harned Hall 320 Phone: 963-5777 Email: dhui@tnstate.edu Some slides in this lecture are borrowed from David Tissue’s seminarSome slides in this lecture are borrowed from David Tissue’s seminar

2. What Controls Climate? Solar radiation input from the Sun Distribution of that energy input in the atmosphere, oceans and land

3. Relationship between Sun and Earth Major Impact on Solar Radiation The pacemaker of the ice ages has been driven by regular changes in the Earth’s orbit and the tilt of its axis Diagram Courtesy of Windows to the Universe, http://www.windows.ucar.edu Tilt of the Earth’s axis relative to the Sun is 23.5o, giving rise to 4 seasons. The tilt of Earth’s axis varies from 22.5 to 24o. Affects energy received by different part of the globe. 41,000 yrs. Diagram Courtesy of Windows to the Universe, http://www.windows.ucar.edu Tilt of the Earth’s axis relative to the Sun is 23.5o, giving rise to 4 seasons. The tilt of Earth’s axis varies from 22.5 to 24o. Affects energy received by different part of the globe. 41,000 yrs.

4. Now we enter a new era in history of life on earth. One single species –humans- may have the ability to alter earth’s climate We will exam how human activities are che 30oC lower than without greenhouse gases Role not same for all these gases Now we enter a new era in history of life on earth. One single species –humans- may have the ability to alter earth’s climate We will exam how human activities are che 30oC lower than without greenhouse gases Role not same for all these gases

9. Why do we say it’s human’s problem How do we know CO2 is increasing?Why do we say it’s human’s problem How do we know CO2 is increasing?

10. We measure it directly Charles David keeling We measure it directly Charles David keeling

11. Figure 29.5Figure 29.5

12. Figure 29.4Figure 29.4

13. Tree carbon per hectare by U.S. county

14. Photosynthesis and respiration: 2 Gt y-1, sink Another way is to react with CO2, Photosynthesis and respiration: 2 Gt y-1, sink Another way is to react with CO2,

15. Therocline, limited the water transfer at the surface below, thus, limiting the abosroption ability. Long-term mixing takes hundreds of years. 70-200meter, total depth 2000 m Not mixed well. Global conveyor belt takes hundred of yearsTherocline, limited the water transfer at the surface below, thus, limiting the abosroption ability. Long-term mixing takes hundreds of years. 70-200meter, total depth 2000 m Not mixed well. Global conveyor belt takes hundred of years