Twenty-Five Years of “Thinking Green” -In 1971 Barry Commoner advanced four laws of ecology that have had a major impact on our thinking in classic book The Closing Circle. 1.Everything is connected to everything else. 2.Everything must go somewhere. 3.Nature knows best. 4.There is no such thing as a free lunch. What do these laws convey in the context of environmental science?

Twenty-Five Years of “Thinking Green” -hydrocarbon emissions from automobiles decreased by >50%. -number of large cities violating clean-air standards has dropped from 40 to 9. -lead emissions reduced by 98% because of the use of unleaded gasoline. -industrial toxic waste spills cut by 43%. -many species have been removed from the endangered species list. -mandatory recycling laws have been implemented in 6600 U.S. cities million acres have been set aside as wilderness areas. -since 1979 the country has invoked energy savings = to five times all the new sources combined. -the number of environmental groups on college campuses increased from 50 in 1989 to over 2000 in 1995.

Earth Systems and Cycles A system is a set of (components) which are interconnected (related and operate together) to one another. The universe is the only truly isolated system where there is no exchange of energy or matter through its boundary. The earth may be considered a closed system where there is only an exchange of energy through its boundary. Open systems such as the hydrosphere or lithosphere exchange energy and matter over their respective boundaries.

Earth Systems and Cycles In open systems linkages between components cause mutual adjustments (feedbacks) between components. As one variable affects a second variable, the second variable causes a change in the first variable. -Negative Feedback (self-regulation) -Positive Feedback (snowball effect, self-enhancing)

Earth’s Energy Cycle 1 watt = 1 joule of energy per second or 1 joule will produce 1 watt of power for 1 second.

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Earth’s Energy Balance: How is the earth’s carbon cycle tied to its energy balance?

Hydrologic Cycle: Reservoir and Fluxes (shown by red arrows.

ReservoirPercent of Total Oceans97.25 Ice Cap/Glaciers2.05 Groundwater0.68 Lakes0.01 Soil Moisture0.005 Atmosphere0.001 Streams/Rivers Biosphere

ReservoirAverage Residence Time Seasonal Snow Cover2 to 6 months Ice Cap/Glaciers20 years to millenia Groundwater (shallow)10 to 100’s of years Groundwater (deep)1000’s of years Lakes50 to 100 years Soil Moisture1 to 2 months Atmosphere8 days Streams/Rivers2 to 6 months

Seismicity and plate tectonics. Note the relationship of depth of foci and tectonic plate boundary.

Relationship between active volcanism and tectonic plate boundaries.

Population doubling time = 70/growth rate (%).

Compare the population doubling time of the African nations versus North America or Europe.

Per capita carbon dioxide emission by country.

Global carbon dioxide production by country.

Relative importance of atmospheric gases and particulate matter on global warming versus cooling.

Anthropogenic concentrations of CO 2, CH 4 and N 2 O) over the last 10,000 years (large panels) and since 1750 (inset panels). Measurements are shown from ice cores (symbols with different colors for different studies) and atmospheric samples (red lines). The corresponding radiative forcings relative to 1750 are shown on the right hand axes of the large panel (IPCC, 2007). The atmospheric concentrations of CO 2 and CH 4 in 2005 exceed by far the natural range over the past 650,000 years.

What potential feedback mechanisms would result from decreasing sea ice and what effect would this have on long-term climate change? What effect would loss of sea ice have on sea level rise?