1. Welcome to Planet Earth

2. Sustainability WATERIn this course we will focus on one environmental resource important to human populations: WATER When populations grow too large, they can exploit all resources in a region and are then forced to emigrate Can you picture a world in which there is no room or resources for human life?

3. Population Growth There are approximately 5.8 billion people in the world The global birth rate is about 27 births per 1000 people per year How many babies were born in the last 3 minutes? What additional information would you need to know to calculate the increase in world population over the past 3 minutes?

4. Projected population growth Figure 1.12 on page 12

5. Why are there regional differences in population growth?

6. Where do most people live? Why?

7. Population density in the Mid- Atlantic Bight

8. Earth is always changing Some changes happen on time scales we can observe: the tides rise and fall, the seasons change Other changes occur over long time periods and we must infer their presence: mountains are built and eroded, plants die and become fossil fuel Most resources on Earth are created much more slowly than we consume them

9. Geochemical Cycles What is a cycle? Reservoirs in the water cycle Fluxes in the water cycle Box models

10. How do you know a cycle when you see one? What are some everyday examples of cycles?

11. Dictionary definition of cycle: Any period of time or complete process of growth or action that repeats itself in the same order

12. The basics of a geochemical cycle Reservoirs - a place where the matter accumulates Fluxes – transfer of matter from one reservoir to another Residence time – the amount of time an average “piece” of matter (molecule, atom) resides in the reservoir.

13. Residence time is calculated: Amount of matter in reservoir Removal rate (or supply rate) Let’s create our own example!

14. Focusing on the hydrologic cycle

15. Major reservoirs Oceans97.5% Glaciers 1.81% Surface water (lakes, streams) 0.016% Soil moisture 0.005% Atmosphere 0.001% * Nearly all of the water on earth is in the ocean and glaciers

16. Major fluxes Condensation Precipitation Infiltration Run-off Evapotranspiration We will define each of these today and then spend the next few weeks talking about each in detail.