Wed. May 1
- HW5 and Writing Stage 3 returned

- Information sheet for final exam (Friday May 10, 11-1 in Space Sciences 308) handed out.
- Possible schemes to decrease CO2 greenhouse emission and/or counteract global warming, including pumping CO2 into the deep ocean where it can dissolve in sea water, and fertilizing the ocean with iron to promote primary production that might be currently limited by this nutrient.
- Linkages between enhanced greenhouse effect (global warming) [EGH/GW] and tropospheric ozone and acid rain [AR] problems. Linkages between EGH/GW, AR and stratospheric ozone problem.
- Information on global change and past environments from ice cores, packrat middens, pollen and tree rings. Glacial-Interglacial cycles

Mon. Apr. 29
- Q6 returned and answers discussed
- The problem of trying to identify global warming from the envelope of natural variability in climate.
- Temperature trends over the past 150,000 years, including glacial and interglacial periods.

Fri. Apr. 26
- Quiz 6; GA6-evaluating the spin doctors

Wed. April 24
- Temperature trend of last 150 years (about 0.7-0.8 °C increase)- modeled best when both solar and volcanic activity (natural) and greenhouse gases (anthropogenic) are included; the greenhouse gases seem to have been most effective in the mid to late-20th Century, with exponential increase in greenhouse gas emissions like CO2, CH4 and N2O, although sulfur emissions also increased.
- Radiative forcing- our understanding is "very high" that contributions to global warming by greenhouse gases have been important (about 2.5 W/m2, versus total insolation of 350 W/m2), with the order of importance= CO2 > CH4 > halocarbons (such as Freon) > N2O. Models indicate that a doubling of CO2 from 275 (pre-industrial) to 550ppm is expected to increase global temperature by 2-3 °C (much greater at high latitudes where all the ice is); other contributions are less certain and may either contribute to increasing or decreasing radiation (temperature), like tropospheric ozone, stratospheric ozone, sulfate and other aerosols, etc.
- NATS-101 obligatory sword fight, with instructor's head being cut off by Li.
- There are many scenarios of CO2 emissions and CO2 concentrations possible in the 21st Century. The consequence, seen in an ensemble of various scenarios of per capita fossil-fuel usage, alternative energy implementation and population growth, is an increase in temperature by 2100 of 1.5-5.5 °C, and increase in sea level of 10cm to 90cm.
- "Likely" changes in next 100 years- decrease in snow cover, pack ice, glaciers and ice sheets (but Antarctic ice sheet will gain mass); increase in sea level mostly from thermal expansion and from melting to a lesser extent; increased Asian monsoon variability; more active hydrologic cycle; thermohaline circulation weakening, but any consequent cooling in N. Atlantic countered by warming from G-H gases; El Niño may not change in strength or frequency, but it teleconnected influence may change in terms of precipitation, flooding and drought.
- Feedbacks- positive feedbacks reinforce a change or process that has already take place; a negative feeback counteracts a change or process that has taken place. For example, if warming by CO2 is the initial process, then resulting increased evaporation could lead to more water vapor in the atmosphere that could contribute to more clouds, which could reflect more incoming sunlight, thereby decreasing temperature and counteracting the CO2°C warming effect.

Mon. April 22
- HW4 handed back; Linah will send out information on answers to listserve.
- Sample quiz 6 handed out.
- Photochemical smog: temperature inversion= extreme stability [like the stratosphere], i.e., they inhibit vertical motion; auto emissions usually check for particulates, unburned hydrocarbons ("HC" or VOCs), and CO; catalytic converters on automobiles are designed to convert VOCs to H2O and CO2, and NOx to N2; strong oxidizing capacity of ozone can affect respiratory system, degrade chlorophyll in plants, break down rubber products (tires, seals, belts, electrical cords).
- Stratospheric ozone: formed when UV splits O2 and one of the O atoms combines with and O2 molecule to form O3; destroyed in reactions with NO, Cl (freons, CFC), methane, and potential Br and F (CO usually converted to CO2 before it can destroy stratospheric ozone); strong decrease in stratospheric ozone concentration above Antarctica since 1970; large increase in extend of ozone depletion above Antarctica- this is "ozone hole" (unrelated to global warming); increased UV-B reaching surface (because there is less ozone in stratosphere to absorb it) is of greatest concern for our health (skin cancer, cataracts, premature ageing, vitamin D) and health of plants whose photosynthesis and growth may be reduced and damage to DNA increased; Montreal Protocol in 1987 to stop manufacture and trade of CFCs.

Friday, 19 April 2002
- Stage 3 writing collected.
- More acid rain:
effects on cultural heritage, aquatic ecosystems, terrestrial systems; "buffering" (neutralization) of acid rain in carbonate terrain, whereas greatest negative impacts in granitic terrain such as the Northeast and Canada; changes in pH of rain in northeastern US through time; changes in pH of European rain, especially Scandinavia; damage to forests and aquatic ecosystems; prospects for worldwide future emissions of NOx and SO2.
- Photochemical smog: formed naturally during lightning discharges; formed largely artificially in presence of nitrogen oxides, VOCs and sunlight; however, in natural environments where there are NOx and VOCs (like terpenes from plants) photochemical smog could without human inputs; more likely to be formed in winter in large northern cities, but plenty of sunlight in cities such as LA, Phoenix and Mexico City to form ozone throughout the year; reduction of urban ozone possible by reducing concentrations of reactants, especially VOCs and nitrogen oxides many fuel pumps now designed to reduce loss of fuel vapors; temperature "inversions" promote build up of pollutants.

Wed. April 17
- Review answers to Q5; more info on writing assignment.
- Primary pollutants (directly out of the smokestack or tailpipe): such as VOCs (volatile organic compounds), nitrogen oxides, sulfur oxides, carbon monoxide (CO) and particulates; Sources dominated by transportation, power generation, industry [all primary pollutants derive from the fuel (for example coal can contain lots of sulfur), except for nitrogen oxides whose nitrogen derives primarily from air N2]
Secondary pollutants (formed by transformations of primary pollutants frequently involving water, oxygen and/or sunlight): such as sulfuric acid (from sulfur oxides), nitric acid (from nitrogen oxide) and ozone (tropospheric ozone the product of interaction of nitrogen oxides, VOCs and sunlight)
- Emissions testing of automobiles commonly targets VOCs (unburned hydrocarbons) and CO.
-Acid rain: pH scale; acid rain often defined when pH<5-5.2. The pH when background atmospheric CO2 dissolves to form weak carbonic acid is about 5.5-5.6, and sometimes other natural acids including organic acids can make the pH a little lower; thus rain from "clean" areas is slightly acidic); eastern US emissions dominated by sulfur dioxide whereas western US emissions much more related to nitrogen oxides;

Mon. April 15
-Western Water problems including demand, chemical pollution from pesticides/fertilizers/ herbicides, pollution from landfills, pollution from industry (such as TCE in Tucson), "safe yield" and groundwater "mining" (and cone of depression), land subsidence, and salinity build-up in soils.
-Low water-use crops and drip irrigation as agricultural solutions.
-Demonstration of porosity with "sand" and water, showing 35-40% of the sand was empty space that could be filled with water; this is equivalent to an aquifer in which a large volume of water is being held in the "pore" spaces between mineral grains.
- Demonstration of soil surface area with one gram of soil; importance of clays to soil surface area because it provides the locations where essential cations (like potassium or calcium) are located and available to the plant roots.
---Quiz 5

Fri. April 12
- Stage 2 of writing project returned along with numerical grade and comments.

-Final Stage 3 is due on Friday, April 19, with all of the following, improved as indicated in comments:
1a. revised positives and negatives
1b. revised title
1c. revised text of your essay/paper
1d. revised references
2. the Stage 2 paper with grade and comments
Group Activity 5- Developing a plan to reduce our influence on radiative forcing.

Wed. April 10
-Handout sample quiz 5
-Water perturbation/degradation
-[Water requirements for a western society]; world-wide use of water domestic/irrigation/industry); above and belowground water resources; hydrologic subdivisions; water supply and "withdrawal" (total water withdrawn) vs. "consumption" (portion of withdrawal not immediately returned to source- lost to evaporation, transpiration, crops, products, humans); decline of water table in many places using groundwater; ground subsidence.
-Point and non-point sources of pollution
[Eutrophication (enhanced plant growth resulting from excess nutrients in water; usually leads to loss of oxygen when increased load of dead organic matter results in enhanced decomposition consuming oxygen)]
Central Arizona Project (CAP)- water from Colorado River to Arizona metropolitan areas Distribution of Colorado River water among western states; reconstruction of Colo. R. flow using tree rings suggests the amount of water measured in the first couple of decades of the 20th Century (about 15-16 million acre-feet per year) to be apportioned among states was actually 1.5-2 million acre-feet more than real average over the last 400 years (13.5 ma-c per year). This means more water was apportioned in legal agreements (compacts) than is likely to be available on average!

Mon. April 8
- Handout with tips on writing good paragraphs and Soil/Water Degradation.
- Historical and ancient historical observations of water/soil perturbations (cont'd)- dust from Sahel and Mongolia transported thousands of miles.
- Natural events impacting soils= floods, landslides, glaciers, wind, subsidence, drought, waves.
- Anthropogenic activities impacting soils= mining, agriculture, logging, dams, transportation, subsidence, wells
Soil Degradation:
1. Soil Erosion (57% by water, 29%by wind) in US this is erosion averages about 10 tons per hectare
Consequences: A- loss of fertile soil (reduced production; more runoff; less water storage in soils; soil harder to till B- impacts on surface water (higher flood levels; reservoirs can fill in with sediments; turbidity (muddiness) can impact aquatic life) Wind can abrade leaves and expose roots
2. Physical (2-3%) excessive compaction, water logging)
3. Chemical (12%) salt build-up; stripping of nutrients; excess fertilizers; pesticides/herbicides; wet/dry deposition (acid); industrial wastes/spills.
- Anthropogenic causes of soil degradation- overgrazing, deforestation, agricultural practices, fuelwood gathering, industrial & waste pollutants.
- Changes in erosion related to land-use change (example the Washington DC area).
- Water perturbation/degradation.
- Water requirements for a western society (household, agriculture, industry).

Fri. Apr. 5
-Handout of soil profiles/classification and rates of soil erosion.
-Estimation of Carbon (CO2) gas emissions from Great Lakes forest fire(s), about 0.1GtC in about 3 days; compared to 6GtC from fossil fuels in a year, 1-2 GtC emitted annually from tropical deforestation, and about 0.1GtC from the big Black Dragon fire in China/Siberia in 1987. Other gases including N and S gases are transferred from biosphere to atmosphere by biomass burning and wild fires. Photograph of my relatives.
-Tropical forest deforestation carbon inputs to atmosphere compared to fossil fuels and to non-tropical deforestation over the past 150 years, and projections for future (Fig. 8.8)

-Begin Soil and Water "perturbations" lectures with wisdom of Jack Handy.
- Soils are composed of layers known as "horizons":

A horizon tends to be organic-rich and materials tend to be leached from this horizon downward;

B horizon tends to accumulate materials leached downward, including clays and iron oxide, and in western US carbonate ("caliche") accumulates in this horizon.

C horizon is partially weathered horizon below B.

Soil classification by texture includes clay-silt-sand content and soils that have intermediate amounts of these 3 grain sizes are known as "loams".
Historical and ancient historical observations of water/soil perturbations- Attica (Greece) deforestation and grazing 2000 years ago; salinity impacts on agriculture in Mesopotamia and Upper Nile civilizations thousands of years ago; Aswan Dam in 1900s; salinity problems in 1900s in Iraq, Iran, Pakistan, Peru, Argentina

Mon. April 8
- Handout with tips on writing good paragraphs and Soil/Water Degradation.
- Historical and ancient historical observations of water/soil perturbations (cont'd)- dust from Sahel and Mongolia transported thousands of miles.
- Natural events impacting soils= floods, landslides, glaciers, wind, subsidence, drought, waves.
- Anthropogenic activities impacting soils= mining, agriculture, logging, dams, transportation, subsidence, wells
Soil Degradation:
1. Soil Erosion (57% by water, 29%by wind) in US this is erosion averages about 10 tons per hectare
Consequences: A- loss of fertile soil (reduced production; more runoff; less water storage in soils; soil harder to till B- impacts on surface water (higher flood levels; reservoirs can fill in with sediments; turbidity (muddiness) can impact aquatic life) Wind can abrade leaves and expose roots
2. Physical (2-3%) excessive compaction, water logging)
3. Chemical (12%) salt build-up; stripping of nutrients; excess fertilizers; pesticides/herbicides; wet/dry deposition (acid); industrial wastes/spills.
- Anthropogenic causes of soil degradation- overgrazing, deforestation, agricultural practices, fuelwood gathering, industrial & waste pollutants.
- Changes in erosion related to land-use change (example the Washington DC area).
- Water perturbation/degradation.
- Water requirements for a western society (household, agriculture, industry).


Wed. April 3
- Quiz 3 handed back; Make-ups for GA4 on Monday 9-10, 11-12 and 2-3.
- After Fri. April 12, a student can only earn 2 EC points.
- Modern forests- 4-5 billion hectares world wide, estimates vary depending on definitions of forests and woodlands;
50% of tropical forests (S. America, Asia, Africa) have been cut in last 200 years; tropical forests may have distinct wet/dry seasons related to the position of the ITCZ; tropical forest characterized by great biodiversity, including diversity with height; a genetic "storehouse" possibly containing many new compounds that could become cures and treatments for out illnesses and ailments ("Tropical Pharmacy"); about 30% of all terrestrial NPP; contains 1/3 of all carbon in terrestrial biomass, but soils only contain a small fraction (4%) of all carbon in soils world-wide; very tight nutrient cycling and retention promoted by mutualistic fungi, dense canopy that inhibits erosion, leguminous (N-fixing) trees.
- Reasons for deforestation: debt repayment (some woods are a very valuable commodity); resettlement (the only land available to poor may be forested areas that they must work by hand to own); conversion of forest to pasture; international logging; hydropower (impounding water behind dam can inundate forests); fuelwood (cooking and heating).
- Deforestation in U.S. (we are not without blame, which makes it somewhat difficult to tell developing tropical countries what to do)- Great Lakes forest fires of Oct. 8-11, 1871. Forest was considered inexhaustible resource by settlers and commercial interests moving eastward from East Coast from early 1800s to Minnesota in late 1800s. Combination of unusually dry climate, common occurrence of fires and sudden extremely windy conditions resulted in forest fires that burned over 2 million hectares, killing over 1200 people in Wisconsin (Peshtigo-Williamsville) and hundreds more in Michigan (same dates as Great Chicago Fire). Fires affect atmospheric chemistry and are part of biogeochemical cycles.

 

1 April 2002 (Monday)
- Quiz 4; Stage 2 of writing project turned in.
- Population trends (from UN Report-world increasing 1.2% per year currently; life expectancy is increasing in both developed and developing nations (World Population Prospects, the 2000 Revision: http://www.un.org/esa/population/unpop.htm.
- Consequences of Industrial (developed) society, good and bad- food availability, transportation (cars), move to suburbs from central urban areas, energy-saving gizmos, 5% of world uses 1/3 of world power, pollution.
-Biosphere changes
-Exotic (invasive) species
-Land-use changes (urbanization, conversion of land to grazing, agriculture, transportation [roads/dams/reservoirs], deforestation)
-Past forests (300-350 my ago [Carboniferous], 40-100 my ago [Cretaceous]; evidence found in coal beds.
-Climate can affect type and distribution of forests, eg, warm conditions 65 my ago promoted expansion of temperate forests, and ice ages resulted in shifting of forest southward in N. America and Europe

29 March 2002
- Reminders about Stage 2 of writing due on Monday, Quiz 4 on Monday (Still missing stage 1 from about 2 dozen students).
Group Activity 4- "Gambling on the Future"

 

Wed. March 27
- Handout sample quiz 4; Handout Homework 4 with map of world population on back.
- Example of Stage 2 of writing project- it will be posted on course web site.
- Mention of Tuesday's ABC Nightline on "Weather Beaten", and possible linkage of unusual weather with global warming. Drought situation currently in US, particularly on East Coast and west, and potential influence on water resources and fire this summer.
Mention of President Bush's new EPA initiatives for "clean skies" (reduction of NOx, SO2 and Hg) and "global climate change" (reduction of greenhouse "intensity" over next 10 yrs).
- US ZPG has not been reached because of (1) death rate is falling because of improved health services, (2) about 1million people immigrate to US per year, (3) still many people in pre-reprodocutive and reproductive age groups. If fertility rate went to 2.1 children per woman, the population would achieve ZPG more rapidly.
- World population about 6 billion (similar to number of tons of carbon being released from fossil fuels each year); 80% of the population in Asia, Latin America, Africa. World population increased going from Stone-Age to Agricultural Age and then from Agricultural Age to Industrial Age. In past, technological advances in society would result in decreased population growth rate, but will it happen for developing and Third World countries in the future?
- Issues associated with population
Food- (1) natural ecosystems converted to artificial agricultural systems with degradation of environment and loss of biological diversity, (2) food production in which animal protein is produced (eg, cattle), results in loss of much of the original energy (90%) in the original plant matter, (3) poor countries may used much of their land to produce cash crops for export rather than food to feed their own population.
- Energy- Wood was primary fuel for heating and cooking 200-1000 years ago and resulted in deforestation of Europe and China; Coal became and alternative fuel as early 500 years ago when timber was depleted, it then fueled the Industrial Revolution beginning about 200 years ago, and simultaneously a movement of population to cities was promoted; Oil first produced in 1850s in US and production increased rapidly when automobiles invented; Natural gas was primarily a waste product 100 years ago, but now is a major and preferred fossil-fuel alternative.

 

Mon. March 25
- Unfinished C-cycle business
-Seasonal CO2 changes, and difference with latitude ("seasonal biomass")
- In addition to CO2, there are other carbon-containing gases that are GH gases:
methane (CH4) is increasing, and is about 45 times more effective as a GH gas than CO2 (fortunately it is a much lower concentration than CO2). Sources include cattle, termites, decomposition (swamps), gas flared from oil wells and lost from pipelines.
CFCs, like Freon, had been increasing in atmosphere. Man-made gases that are strong GH gases and cause other environmental problems.
- "Compounding"= building up of something on the basis of its rate of growth; for example, in a bank account money can earn interest at some annual rate by compounding.
- "Rule of 70"= you can determine how long it will take to double by dividing the annual rate of increase into 70. For example, a city whose population is increasing 7% per year will double its population in 10 years (70/7 = 10)
- Population and rates of growth on different continents.
- Population density (number of people per unit area) is greatest in Japan, Asia and Europe; lowest in Australia.
- Energy use per capita (per person) is highest in US, Europe, Former Soviet Union, Japan. Related to Kyoto Protocol, calling for developed nations (primary energy users) to cut back their CO2 input to the atmosphere to 1990 levels; but developing countries (China, India) are not expected to do so.
- Hypothetical population growth curve stages=> 1. lag, 2. exponential, 3. stationary, 4. death
"Carrying capacity"= optimum population that can be sustained, and depends on natural resources (incl. food), energy, waste, interactions)
- Characteristics of populations (these can influence the trajectory of population change): birth rate, death rate, sex ratio, age distribution of populations, dispersal (emigration/immigration)
ZPG (zero population growth); US is approaching it.

Fri. March 22
- First writing stage returned (scored 1-5, where 3 is ok, above 3 is better, below 3 is worse).
Information on proper bibliographic citation is given in the following:
Proper citation of electronic resources: http://www.ar.utexas.edu/Planning/students/citation.html
Style in bibliographic citation for biology: http://www.wlu.edu/~hblackme/biology/style.html
- Second writing stage is due on April 1, and it should include your references in proper format.
- Homework revised schedule: HW4 assigned 3/27, due 4/8; HW5 assigned 4/12, due 4/22
Discussion of just-released article (www.aaas.org) about tree rings and the possibility they might indicate that part (900-1000AD) of the Medieval Warm Period might have experienced similar warming to that seen in the late 20th Century. (This is highly debatable)
- Radiocarbon and the "Suess Effect" (dilution of 14C observed in tree rings 1850-1950)
Direct CO2 measurements, beginning with Keeling's measurement site established in Mauna Loa, Hawaii, and providing continuous measurements since 1958; now a world-wide network. Current CO2 concentration is almost 370 ppm.
- Connection of rising CO2 to other cycles (such as N and S) when NOx and SO2 are produced during combustion.
Past CO2 concentrations:
- Last 150,000 years=> current peak is similar to one that occurred 135,000 years ago, and a minimum (190 ppm) occurred about 20,000 years ago;
- Last 600 million years=> evidence that most of the period had CO2 concentration from about 4 to as many as 16 times the current CO2 concentration.
- Thomas Malthus and his hypothesis that world population was going to increase disastrously unless checked by war, famine and disease.

Wed. March 20

- (today is vernal equinox, Vern! 12 hours light, 12 hours dark)
- Collapse of part of Antarctic ice sheet the size of Delaware in the last few days/weeks.
- Equinox and solstices, related to seasons, length of day (versus night), solar intensity, ITCZ.
- Trends in fossil-fuel and cement CO2 emission world-wide.
- Cement manufacture is a source of CO2 in process of isolating lime for cement.
- Reserves of oil, coal and natural gas in U.S. (lots of coal and natural gas, relatively little oil)
- How do we know fossil-fuel CO2 is being retained in the atmosphere?
1. radiocarbon dilution evidenced in tree rings (the "Suess Effect")
(Living matter is in equilibrium with natural atmospheric radiocarbon (14C) content, but when it dies, the radiocarbon decays (half-life 5700 years) without replacement. By measuring the amount of radiocarbon left, we can determine age since material went out of equilibrium with atmosphere. Wood, bones, shells, hair, fur, feathers, teeth, etc can thus be dated back to about 50,000 years old)
The atmospheric dilution seen in radiocarbon of tree rings over the last 150 years is consistent with "dead" carbon (from fossil fuels) being retained in the atmosphere.

Mon. March 18
- Field trip overview; reminder of mid-term questions to be answered to listserve by Wed. at 3pm; reminder of first step in writing assignment due on Wed.
- Imbalanced carbon cycle in IPCC carbon cycle figure- "anthropogenic" (human-generated) inputs of carbon the atmosphere from fossil fuels and cement manufacture.
- The "missing sink" problem (maybe better called the "unidentified sink" problem)=> about 6GtC are going into atmosphere from fossil fuels per year + another 1-1.5 GtC from land-use change (largely Amazon deforestation) =7-7.5GtC.

HOWEVER, we can only account for sinks for this excess carbon of about 3.3 GtC in the atmosphere (about 50% of the fossil-fuel carbon release) + 2GtC in oceans by inorganic dissolution=5.3GtC. So where is the rest of the carbon (1.5-2GtC) going, ie, what is the "missing sink"? There must be natural "sinks" for CO2 that have taken it up; a large amount of research money and effort is going to identifying and understanding those sinks.
- Exponential rise in carbon releases (coal, oil, natural gas, cement, flaring); coal was dominant until about 1970, but oil is as great or greater now, and natural gas usage is growing rapidly; global per capita fossil-fuel use is about 1 ton per person per year and has been fairly steady over the last 30 years, which means rate of fossil-fuel use is increasing at the same rate as population.
Reserves of coal, oil and natural gas are enough to sustain us well into future, but their distribution is variable, for example US has large reserves of coal and natural gas, but not oil.

Fri. March 8
- Return mid-term exam (average 72%). Review answers to #46 and #47. For #47, what was intended as a reward for coming to appointment with Prof. Leavitt, turned into a ghoulish house of horrors for many of you. Students were assigned questions #1-45 and #48 to provide a correct answer to the listserve by 3pm, Wed. March 20.
Carbon cycle:
- Main reservoirs= atmosphere (CO2,CH4,CO gases), biosphere (CH2O=plant matter; sometimes subdivided as living part and dead part[soils and litter]), ocean (sometimes subdivided into surface ocean and deep ocean), rocks and sediments (including carbonate rocks, fossil fuels and kerogen), hydrosphere (dominantly dissolved CO2,CO3--,HCO3-)
Main fluxes= photosynthesis, respiration (decomposition, natural combustion), dissolution in ocean, diffusion out of ocean; and now "anthropogenic" sources (for example, internal combustion)
- Imbalance of carbon cycle related to energy production, transportation, heating, agriculture and other needs of modern society
Consequently, fossil-fuel CO2 release has exponentially increased from less than 0.1 gigatons 150-200 years ago to over 6 gigatons per year of carbon today (1 gigaton[GT]= 1 billion tons = 1015 g carbon); political events (Great Depression, WWII, 1970s oil embargo) had a visible but minor effect on this trend.

Wed. March 6
Mid-term exam [55 minutes]

Mon. March 4
- Handed back quiz 3 and went over answers; also handed back Homework 3 and unclaimed other graded work; handout of global carbon cycles.
- Study recommendation- sample quizzes, real quizzes, you lecture notes, my lecture synopses on course web page, readings, homework, group activities; it will be through today's lecture.
- There will be review session Tuesday, 4:30-5:30 in room 312 Space Sciences next to our classroom
More selling of advertisements, even when they are for poisons and carcinogens, i.e. the tobacco ads. You don't see iron lungs, chemotherapy treatments, surgery recovery rooms and scars, or oxygen bottles being rolled along by elderly people with tubes in their nose. Rather they try to sell some positive images of apple pie, strength, vigor, youth, romance, sex, health, old-fashioned values, etc.
Oxygen cycle and its effect on both atmospheric oxygen and carbon dioxide over the last 600 million years, associated with major coal-forming periods 300 million years ago and 50-100 million years ago.
- Sulfur cycle and recently-learned importance of sulfur compounds (carbonyl sulfides and dimethyl sulfide) naturally emitted from ocean that may influence climate by their effect in developing clouds as "condensation nuclei" or on high atmosphere (stratosphere) sulfate, both of which can influence albedo and reflection of incoming solar radiation.
- Carbon cycle schematic diagram, showing different reservoirs and primary forms of carbon [atmosphere- CO2, CO, CH4; hydrosphere- HCO3-, CO3-, dissolved CO2; biosphere- CH2O; lithosphere- limestone (CaCO3) and kerogen (oil, coal, and finely dispersed organic matter).

Fri. March 1
-Some good questions asked by students in the first few minutes (biomass and eating low on food chain, TH circulation vs. upwelling, TH circulation and climate, "horse latitudes" and "doldrums").

- Students reminded of last opportunities of appointments to meet Prof. Leavitt (drop in today until 4pm and Monday 8:30-10am and 5-6pm); make-up GA3 Monday; possible review session, 4:30-5:30 Tuesday and opportunities for questions in last 10 minutes of class Monday.

- MID-TERM EXAM WED. MARCH 6 "Selling" example related to NOVA "Methuselah Tree" program and water vs. real estate/ gambling/resorts in Las Vegas.
- Reminder that the "box models" of biogeochemical cycles help us to better understand interactions among parts of the Earth system, and to identify problems related to changes in fluxes or changes in reservoirs
Calculation of MRT and turnover rate using numbers for atmosphere in carbon cycle; students to try to calculate MRT of carbon in ocean reservoir by Monday
-Oxygen cycle- reservoirs, fluxes and O2 levels reconstructed over the last 600 million years

Wed. Feb. 27
- Handout of Ca and C biogeochemical cycling
- Mention of autotrophs and heterotrophs (the former [=producers] can manufacture their own food, the latter must eat other organisms [=primary and secondary consumers]), and field trip where we will see biomes of different productivity.
- Modern systems have great abundance of species (especially insects), but extinction rates seem to be high. There have been massive extinctions in the past, unrelated to human activity:
- Permian-Triassic extinction event the largest of the 6 major extinction in the Phanerozoic (last 600 million years); evidence from geological record suggesting the possibility it was driven by large volcanic eruptions (Siberian traps) or meteorite/comet impact. Evidence suggests loss of land plants and lots of sediments, and many "Bucky Balls" (fullerenes) containing inert gases whose isotopic composition suggests extraterrestrial origin. Some of the extinctions have recently been found to be not as "major" as suggested in text.
- "Box Models" of biogeochemical cycles require defining the system and subsystems including the reservoirs (compartments, pools) and predicting and evaluating paths and fluxes between reservoirs.
Terminology: reservoirs/compartments=places where element/compound resides; flux/flow/transfer=rate of movement between reservoirs
- Mean residence time (MRT)= reservoir size/flux in (or out)
- Turnover rate= flux in (or out)/reservoir size
- Calculation of MRT and turnover rate using numbers from calcium cycle
- Examples of persuasive prose that attempts to sell something by making it seem attractive and desirable (real estate, restaurant, dog poop exhibition)

Mon. Feb. 25
- Sample quiz 3 handed out; writing assignment handout; biomass/productivity handout
-Energy and mass losses in going from lower trophic levels to higher levels
-A closer look at abiotic factors of nutrients (eg, major nutrients C,O,H,N,S, and minor nutrients K, Ca, Fe, Mg) and climate; world climate classification map
- Distribution of dry organic matter in biomes (living=leaves,trunks/stems,roots + dead=litter,soil organic matter)

- Contrast of grassland and tropical rainforest biomes that are similar in total organic matter, but differ in distribution (handout)
- Biomass is mass of living organisms (= phytomass + zoomass, which is approximately equal to phytomass alone) (mass/volume; mass/area)
-Primary productivity is amount of plant matter produced [by photosynthesis] (per area per time)
-Gross Primary Productivity (GPP) is total production
-Net Primary Production (NPP) is GPP-respiration losses
-Biomass in oceans is about 0.5% of biomass on continents, but NPP in oceans is almost 1/2 of NPP on continents. Biomass is needed on continents to provide support to reach light, and therefore the continental biomass is dominated by structural components (CHO). Marine biomass does not need the structural components, tends to have a higher ratio of proteins to carbohydrates, and have much shorter life spans than terrestrial organisms
- Distribution of biomass and production on land and water (Figs. 4.11 and 4.12)

Fri. Feb. 22
- Group Activity 3 "

Wed. Feb. 20
- Message sent to listserve for preparation for Friday GA3, including 2 web page readings, a request for you to estimate the amount of beef you eat per week, and reminders to bring a calculator. Group leader received handout with GA3 information in addition to a message on their listserve.
- Tides- primarily caused by gravity force between Earth and moon (and Earth and Sun); 2 high tides in ocean per day because of tidal bulges facing moon (direct gravitational attraction force) and opposite moon (indirect gravitational force associated causing "centrifugal force")
- High biological productivity in upwelling areas and in "estuaries" where fresh water streams encounter coastlines in embayments with highly variable environments of salinity (higher salinity toward bottom and lower salinity at top) and organism associated with tidal mixing and rates of stream flow.
- "Ecosphere"/Biosphere general importance (eg, connected to other parts of Earth system, namely biosphere, atmosphere & lithosphere; involved in biogeochemical cycles of elements such as C,O, N, & S; and its operation in energy and mass tranfer)
- Two primary groups of organisms- prokaryotes, eukaryotes
- Biosphere "biotic components"- trophic (nourishment) levels [primary producers=autotrophs; primary consumers=herbivores; secondary consumers=carnivores; decomposers]
- Food chains and food webs:
90% loss of energy going from one trophic level to the next level above it
Energy consequences of "eating low" on the food chain
- Biosphere "abiotic components"- climate, nutrients (eg, C,O,H,N,S), sunlight, water
- Abiotic and biotic components comprise biosystems (ecosystems)
- Large, easily identified community units are known as "biomes"; interaction of biota and climate on a regional scale. Biomes around the world, such as grasslands (fig. 4.8; table 4.3).

Mon. Feb. 18
- Handout of deep-water formation and Younger Dryas records.
- More "ENSO" (El Niño/Southern Oscillation)- during El Niño events, there is increased precipitation along Peru and Ecuador, but there is reduced precipitation in Amazon, so it is ripe for fires just like the rainforests in Indonesia during El Niños (the opposite occurs during La Niñas).
- Deep ocean currents ("thermohaline circulation", "oceanic conveyor belt")
Requires dense water to start cycle by sinking
- Dense water achieved by

(1) cooling

(2) increase in salinity through

(2a) evaporation or

(2b) freezing

- Densest water forms in Arctic and Antarctic areas of ocean, where there are cold temperatures and salinity greater than 35permil (35 parts per thousand=the average of ocean water).
- The excess salinity in N. Atlantic contributes to sinking of dense water that then moves as a deep current through the S. Atlantic Ocean, Indian Ocean and Pacific Ocean before rising and returning as a warm-water surface current back to the N. Atlantic (to replace water that has sunk to the deep currents).
-Thermohaline circulation transports heat and salinity (salt) as nature tries to even out these imbalances around the world ocean.
-Younger Dryas was an abrupt return to cold conditions about 12,000 years ago, after the last ice age appeared to end; evidence is seen in Calcium concentration of ice cores; it was likely caused by a shift in meltwater discharge from the Gulf of Mexico to the N. Atlantic as melting N. American glaciers retreated; it may contribute to or counteract possible future global change.
- Ocean food chain example
-Ocean "zones": Deep ocean below about 1.5-2km is very uniform (homogeneous) in salinity (35ppt) and temperature (0C); surface zone from surface to 200-500m is highly variable in characteristics, subject to effects of atmosphere and organisms- for example salinity might be 37ppt in tropics but 34ppt at higher latitudes, and temperature might be 20C in tropics but near 0C at high latitudes; the transition zone from about 200-500m down to 1.5-2km is where the characteristics change rapidly with depth

 

Fri. Feb. 15
- Quiz 2 returned; raw average was 16 but 2.5 "quiz adjustment" points were added to raw score; about 10 minutes spent on reviewing answers
- Homework #3 was handed out; due Monday Feb. 25.
- El Niño tends to recur in irregularly from 3-7 years, and strength varies among events
Evidence for El Niño events
- Warm water pooled on east side of Pacific.
- Reduced upwelling off S. American coast and fishing crash.
- Higher sea level in east Pacific than west.
- SOI (Southern Oscillation Index) negative (the atmospheric pressure at Darwin is greater than Australia).
- Westerly winds (west to east winds) in Pacific near equator.
- High precipitation in Ecuador/Peru; Low precipitation in Australia/Indonesia
- During La Niña events conditions are opposite of those listed above.
- The 1982-83 and 1997-98 events were the El Niño's of the Century, and climate in the Southwest was particularly unusual (examples were given).
-"Teleconnections" are the influence of El Niño outside of the confines of the Pacific Ocean Basin; these include statistical correlations of El Niño with climate of diverse locales such as climate effects in the US Southeast and Northeast, eastern S. America (including the Amazon Basin), India, and Africa.
- In addition to El Niño, there is evidence of other cycles on longer scales that may influence Pacific climate and teleconnect elsewhere, including PDO (Pacific Decadal Oscillation).

Wed. Feb. 13
- Quiz 2, First 22 minutes
- Water chemistry- differences in cation and anion concentrations in rainfall, rivers and sea water (that have progressively higher TDS). Some observations:
1. In rainfall, Na+ and Cl- tend to be high near coasts but lower inland (from oceans)
2. Ca++ and HCO3- tend to dominate in rivers even though they do not dominate rainfall (as water percolates through soil and rocks, Ca++ is being weathered and added to water, and very high CO2 in soils [from respiration] dissolves in the percolating water to produce high HCO3-. That percolating water eventually ends up in rivers with all the extra dissolved ions)
3. Na+ and Cl- dominate ocean because they are constantly added to oceans from the rivers, but there are few mechanisms to remove them.
Oceans
- Surface currents- driven by wind; flow in semicircular patterns known as "gyres"; high pressure drives air circulation that drives gyres; direction of circulation is different in the North and South hemispheres; Columbus, Horse latitudes and Doldrums; California Current, Gulf Stream.
- Upwelling along coast and nutrients to support food webs
- El Niño and currents in S. Pacific

Mon. Feb. 11

- Reminder of Sample Quiz 2 and requirement of of people assigned questions to respond before noon Tuesday.
- Global hydrologic (water) cycle-most water in oceans, most fresh water locked up in ice caps, more fresh water in groundwater than surface water. Fluxes between water reservoirs, eg, runoff the primary direct flux between continents and ocean, or precipitation transferring water from atmosphere to land or ocean.
-Pattern of latitude precipitation- highest at equator, and secondary peaks at about 45-55 latitude; minima at about 30 latitude and 90 latitude.
-General circulation (GC)

-Air is rising, sinking and being transported between latitudes in convection cells such as the Hadley Cells that operate near the equator. Where air rises, there is low pressure, cloudiness, storminess and precipitation, whereas when air sinks, there is high pressure, lack of clouds, storms and precipitation. GC cells have air rising at equator, 60S and 60N near precipitation peaks, and air sinking at 30N and 30S and at the poles (deserts). Other GC features such as tradewinds and westerlies and their relation to Coriolis effect.
-TDS (total dissolved solids) represents the amount of material dissolved in water and is usually measured in ppm (parts per million) Rain water typically has very low TDS (a few ppm) and at the other extreme is the ocean (35000ppm or 35 permil or parts per thousand) and Great Salt Lake (150ppt to 280 ppt). Domestic water supplies are generally in the 100-2000ppm range

Fri. Feb. 8
- Handout Sample Q2; 13 students are required to send message to listserve selecting the best answer and providing an explanation why it is correct (by noon Tuesday).
- Quiz 2 is next Wed.
- Homework #2 was handed back with the group packets.
- GA #2, water resources and water health/pollution in foreign countries, and water (pH, conductivity, TDS) in Tucson.
Students who missed GA2 should send e-mail to Prof. Leavitt ASAP.


Wed. Feb. 6
- Acting! Master Thespian!
- Handouts on water and water cycle
- At end of hour, we broke out into groups to delegate responsibilities for collecting drinking
water samples from different places where group members live or work for GA2 on
Friday. All student must bring in information (web or library) about the water resources,
water pollution issues, water health issues related to their group's country on Friday.
- Properties of water
- Strong covalent bonds between hydrogen and oxygen
- Polar water molecule promotes cohesion, adhesion, capillary rise (water pulls itself
upward in small tubes because of cohesion and adhesion), and surface tension
- Latent heat- 600 cal heat required to evaporate 1 g water (major mechanism of heat
transfer from Earth's surface to atmosphere).
- Specific heat- 1cal of heat energy will raise temperature of 1 g of water 1C. Most other
substances, eg: metals, sand, have lower specific heat
- As water cools density increases to 4C (39F), and with further cooling density decreases
Water can dissolve many different types of substance such as salts (like table salt), polar
compounds (like carbohydrates and proteins), and non-polar substance (like CO2 and O2)
more salts and polar compounds can be dissolved in water at higher temperature, but non-
polar gases are less soluble in water at higher temperatures.
- Intro to water cycle- reservoirs where water resides, represented by the amount [mass, volume]
present), and fluxes represented by movement of water between reservoirs [mass per time, volume per time])
Intro to general circulation.

Mon. Feb. 4
- The list of countries assigned to groups for GA #2 was shown; homework for GA#2 described.
- Cause of seasons= tilt of the Earth's axis and whether our hemisphere is tilted toward the Sun or away from the sun as the Earth revolves around the Sun during 365 days.

- Rules of Electromagnetic (EM) Radiation

(1) The hotter the object, the shorter the wavelength of peak radiation (Wien's Law- we calculated peak wavelengths of terrestrial [in the infrared] and solar [in the visible] radiation).

(2) Shorter wavelengths have greater energy.

(3) Energy emitted as EM radiation increases as the 4th power of an objects temperature (An object twice the temperature of another emits 16 times as much energy).

(4) Objects emit visible light (reddish glow) as objects reach a temperature of about 550-600C.
Atmosphere absorbs some wavelengths of terrestrial and solar radiation (Fig. 3.2). Incoming solar radiation has much of its UV radiation removed by oxygen and ozone; outgoing terrestrial radiation is absorbed by greenhouse (GH) gases such as water vapor and CO2.
- Our detailed definition of the greenhouse effect- the atmosphere is transparent to (does not absorb) much of the incoming solar radiation (like the greenhouse windows), but greenhouse gases effectively absorb many wavelengths of the outgoing terrestrial radiation and prevent the energy from escaping to space (like greenhouse windows keeping heat energy in the greenhouse).

- Fig. 3.3 gives us the blueprint for how to change the temperature of our planet or why it might have changed in the past. For example, changing solar luminosity affects incoming solar radiation, changing atmospheric or surface albedo affects incoming solar radiation absorbed in Earth-atmosphere system, changing abundance of GH gases affects amount of outgoing terrestrial radiation prevented from escaping to space.

Fri. Feb. 1

- Announcement of call for e-mails from those who would like to attend the field trip on March 23 to Prof. Leavitt at (sleavitt@ltrr.arizona.edu)

- Reminder of GA #1 make-ups on Monday, Feb. 4 at 11-12 (tungsten), and 3-4 pm (uranium).

- Major gases tend to have constant concentration no matter where and when they are measured, but trace gases tend to be more variable depending on where and when measured (for example, CO2 concentrations vary seasonally with higher values in late winter and lower values in late summer; amplitude of this shift is related to seasonal biosphere by way of photosynthesis).

Sources, sinks and importance of major and trace gases; for example,

(a) photosynthesis produces (source) oxygen (CO2 + H2O => CH2O + O2 in the presence of chlorophyll and with energy from sunlight)

(b) we need oxygen to live (importance)

(c) oxygen can be removed (sink) from the atmosphere in combustion processes.

Temperature structure of atmosphere-- averaged over the whole planet and over the whole year, we see temperature change as we go upward into the atmosphere as follows: Average surface temperature is +15C (Earth’s surface would be -18C if no greenhouse gases were present) As you go further upward, temperature decreases to about -57C at a height of 10 km, which is the top of the lowest atmospheric layer (known as the “troposphere”) The thin layer above the troposphere is called the tropopause where temperature remains constant as you continue to go upward As you continue further upward, temperature then starts to warm in the next layer (“stratosphere”) until it is a balmy 0C at the top of the stratosphere at 50 km Above the stratosphere, temperature is constant in a thin layer known as the “stratopause” and then begins to decrease in the “mesosphere” Cause of Earth seasons.

- Electromagnetic radiation is means by which energy is gained and lost by the Earth.

- Electromagnetic spectrum.

- Earth’s energy budget- short-wave incoming vs long-wave outgoing radiation.

Wed. Jan. 30

 - Homework #2: question #2, you need to go to the following web site to answer the question: http://www.hwr.arizona.edu/Alpine/IGCL/home.html 

- Change in temperature with increasing elevation, example from Tucson to Mt Lemmon.

-  Make-up opportunities for GA #1 will be Monday Feb. 4 11-12 - with Kelly (room 330 Space Sciences element=tungsten) OR 3-4pm - with Li (meet in room 218-1 West Stadium; element=uranium). 

- You must prepare before meeting; instructions were sent to listserve-send Prof. Leavitt an e-mail if you did not receive them. 

- Be on time, or you jeopardize losing this opportunity. 

- Plate tectonics and types of plate boundaries (plates colliding = “convergent” boundary; plates moving apart = “divergent” boundary; plates sliding past each other = “transform” boundary Major natural global change events in the first 4 billion years of Earth history- Earth origin; early heating of Earth and "differentiation" into layers; origin and abundance of life; cyanobacteria and changing atmospheric oxygen concentrations; banded iron formations (BIF) preventing early build up of oxygen; "ice house" and "hot house" periods"; early Sun “paradox” when solar luminosity was 30% less than present and why the oceans did not freeze (answer= greenhouse gases such as CO2 may have been at very high concentrations in early Earth atmosphere).

- Our “sea of air” with highest pressure at the surface and decreasing pressure upward Today’s atmosphere dominated by nitrogen (78%), oxygen (21%), argon (1%) and “trace gases” Origin of atmosphere- "outgassing" of Earth's interior=> H2O condenses to form oceans, CO2 and SO2 dissolve in water; H2 escapes to space, N2 and Ar build up, photosynthesis builds up O2 (after BIF oxygen “sink” was filled) Demonstration of 4 atmospheric gases, some in unusual (cold) forms Demonstration of the relationship of temperature and volume for gases, known as the “universal gas law” => at constant pressure, if you increase the temperature of a gas its volume will increase and if you cool the gas its volume will decrease

Mon. Jan. 28

Reminder for students who did not sign up for interview with Prof. Leavitt to make a appointment with Linah after first looking at class web site to see what times remain.,/p>

Return and review of Quiz 1 with emphasis on Newton’s Laws (Q #7), potential energy and Laws of Thermodynamics (Q #10), and origin of universe (Q #5).

Homework #2 was handed out at end of period- due next Monday Feb. 4 at beginning of class Revisit group activity #1 with slides of mining activities around U.S. and some of the environmental problems associated with mining.

Structure of the Earth

Differences in chemistry among layers (for example low SiO2 in mantle and higher in continental crust, and more Fe in mantle and less in crust) is consistent with Earth’s “differentiation” into the layers early in its history. Crust and rigid upper mantle constitute the lithosphere. The lithosphere rides over the portion of the upper mantle (asthenosphere) that flows (heat from Earth’s interior leads to convection processes in the asthenosphere). The plates move and interact with each other in a dynamic system known as “plate tectonics” There are 3 different types of plate

Fri. Jan. 25

- Announcement that if you do not want your graded work (homework, quizzes, etc) placed in the bins outside the classroom send Prof. Leavitt an e-mail (sleavitt@ltrr.arizona.edu), and we will make another arrangement to get your work back.

- Group Activity 1- Metallic Elements

Wed. Jan. 23

Quiz 1 for 20 minutes near the beginning of hour, students were randomly assigned seats.

- Preparation for first group activity on Friday was discussed- Students were sent e-mail via listserve with questions to research using web or library before Friday’s class.

- Students will bring materials they find to class to help themselves and their group answer the questions.

- You can check your element and group on course web site.

- Law of Universal Gravitation- example of gravitational force exerted by nearest star (other than Sun) on you at birth versus the gravitational force exerted by the doctor who delivers you.

- Structure of the Earth During early stages of Earth history our planet was at least partly molten resulting from heat of collisions and gravitational potential energy converted to heat energy (decay of radioactive elements was also important source of heat over all of Earth’s history) During this early period, Earth began to differentiate into layers with heavier material sinking to interior and lighter material rising to surface. Consequently Earth’s core is made predominantly of iron and nickel (like some meteorites). The mantle layer above the core is primarily magnesium (Mg) and iron (Fe) silicate rock, and the crust on the surface is composed of silicate rock with less Fe and Mg and more K, Na and Al.

Fri. Jan. 18

Origin of Solar System

  Newton’s Laws

 1st- Every object persists in a state of rest or in uniform motion in a straight line unless acted on by an external force to change that state.

2nd- The change in velocity (= acceleration) with which an object moves is directly proportional to force applied and inversely proportional to the mass of the object (a=F/m)

3rd- Every force or action has an equal and opposite reaction (conservation of momentum)

 Law of Universal Gravitation- any and all objects exert an force of attraction between them proportional to the product of their masses and inversely to the distance between them squared. (F= G x (m1 x m2)/r2)

Wed. Jan. 16

Periodic Table (cont’d)

Laws of Thermodynamics        

 First Law- Energy cannot be created or destroyed, but it can be converted from one form to another (examples of energy- heat, like, kinetic energy, electrical energy, potential energy of petroleum, food and gravity)

 Second Law- No energy transformation is 100% efficient or Energy can be converted from one form to another but in all conversions there is formation of some ‘low quality’, ‘non-usable’ heat or Heat cannot be completely converted to work.

Mon. Jan. 14

Announcements:       Homework #1 due at the beginning of class Wed, Jan. 16

Fri. Jan. 11

Homework #1 handed out; Lecture-related photocopies handed out.

Introduction to the  novel of epic proportions (sort of like Star Wars, Bible, etc) known as The

Characteristics of matter

Wed. Jan. 9

Overview of class content (examples of temperature change in last 140 years, last 1000 years and over Earth history of 4.6 billion years; unusual climate of the last 2 years; natural and human-driven change)