NATS101 Introduction to Global Change Section 16
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Aug 21:
Lecture notes shown in class are here.
No slides drawn.
Aug 23: According to Cerceo, a huge volcanic eruption in 535
AD and the consequent catastrophic climate effects should make us
realize that
some climatic disasters are out of our control, but the consequences
of
using fossil fuels are something we have a better chance of affecting.
Our Place in the Universe
Scientific
Notation- a shorthand way of compactly writing very large or
very small
numbers; the power to which “10” is raised in scientific notation tells
us how many decimal places to move to the left or right to write a
number in
expanded notation.
The origin, history and processes in the Universe
and the
material in our planet are embodied in the Periodic Table of the Elements
Characteristics
of matter
All matter
is made of small particles (atoms and their constituents)
Atoms of
the same element have similar chemical properties
Atoms are
not divided by chemical reactions
Chemical
reactions involve electrons; nuclear reactions involve protons/neutrons
Periodic
Table
Elements arranged according to
increasing Atomic Number (number of protons).
(This
arrangement is also related to filling of electrons in discrete
electron
“shells”)
Each
element has name and 1- or 2-letter shorthand notation.
When an atom is “neutral”, it will have an equal number of protons (+) in nucleus and electrons (-) orbiting nucleus. Neutrons (no charge) also can reside in nucleus at the center of atoms.
Only H and He (the most abundant elements in the Universe) were formed in the "Big Bang" 13-15 billion years ago; evidence of the Big Bang event is seen in the galaxies moving away from us at high speeds; the more distant the galaxy, the faster it is moving from away from us; Wavelengths (short wavelengths correspond to low pitch for sound waves, and red color for visible light waves; long wavelengths correspond to high pitch for sound waves, and purple color for visible light waves; see "electromagnetic radiation"); The “Red Shift” associated with the “Doppler Effect” indicates galaxies are moving away from us at high speed.
Elements from lithium (Li) to iron (Fe) (also He) produced in the interior of normal stars by “fusion” processes, i.e., lighter elements being combined to manufacture heavier elements. For example, in our Sun, fusion takes place converting 4 hydrogen atoms (1 proton in each nucleus = 4 nuclear particles) to one helium atom (2 protons and 2 neutrons in nucleus= 4 nuclear particles); the mass of the helium atom is less than the 4 hydrogens, so the difference in mass is what was converted to energy that contributes to the internal heat of the Sun (E=mc2). The energy from such nuclear reactions (involving nuclei of atoms) >> energy from chemical reactions (involving electrons of atoms); The fusion taking place in the Sun and other stars represents a tremendous energy source, and research has been directed at trying to promote controlled fusion reactions on Earth as a limitless source of energy (The world already has many fission reactors in which large radioactive elements such as uranium, decay and release energy)
Elements up to Iron can be produced by fusion because energy is released; Elements beyond (heavier than) iron cannot be produced by fusion, but can be produced by high fluxes of neutrons that are captured in the nuclei of existing atoms; such neutron fluxes occur in interior of massive stars and when stars explode (supernova).
Origin of Solar
System
There was about 10 billion years
between the Big Bang and the origin of our Solar (Sun) system (which
formed
about 4.6 billion years ago)
Our solar system is made of all the
elements of the Periodic Table but only He is being produced in our
solar
system currently (in the Sun); therefore all of the elements had to
have been produced in the 10 billion years
before the solar system was
formed (our system is from the remnants of other stars)
Solar Nebula Hypothesis has solar
system forming from a rotating ball of dust and gases that flattened to
a disk
shape. Most of the mass was in the
center and the pressure and temperature in that environment ignited
hydrogen
“burning” (fusion).
Matter was distributed in the solar system such that the internal 4 planet are more dense and rocky “terrestrial” planets and the outer “Jovian” planets are lower density, “icy” planets composed of lighter elements/frozen gases. There are also satellite planets (moons) orbiting around many of these planets, such as Titan. Several hundred other planets have been observed around other distant stars, but most are quite different than ours (hotter and much, much larger!)
Aug
28: Lecture notes shown in class are here.
Slides drawn in class are here.
Aug 30: Lecture notes shown in class are here. Slides drawn in class are here.
Hand back in-class exercise #1 (map) and #2 (greenhouse effect)
REMINDER: Your term paper topic is due next
Thursday (Sept.
13)- A title with one or two sentences of description/explanation
should be
OK. Try to be explicit and focused; Also
quiz next Thursday
REVIEW: Wien’s Law (λpeak=2880/TK) determines the peak wavelength and at Earth’s temperature (15ºC, 288K) the peak of emitted radiation is at 10um (10 micrometers, infrared), whereas at Sun’s temperature (6000K) the peak of the emitted radiation is at 0.5um (0.5 micrometers, visible).
REVIEW: major atmospheric gases (N2, O2, Ar =most abundant); and important minor atmospheric gases (CO2 and H2O vapor =key contributors to greenhouse effect and to life). Sources (mechanism/process for gas getting into atmosphere), sinks (mechanism for removing gas from atmosphere); for example, photosynthesis is a sink to remove CO2 from the atmosphere (CO2 + H2O => CH2O + O2); respiration (the reverse reaction of photosynthesis) is a mechanism (sink) to put CO2 into the atmosphere, and to remove oxygen from the atmosphere (CH2O + O2 => CO2 + H2O) The same equation can likewise represent combustion processes that also remove oxygen from the atmosphere (sink) or put CO2 into the atmosphere.
Demonstration of 4 atmospheric gases (N2, H2O, CO2 and O2), some in unusual (cold) forms.
Demonstration of the relationship of temperature, pressure and volume for gases, known as the “universal gas law” => the product of volume x temperature is proportional to temperature (PV=nRT), ie, if temperature is decreased, you will reduce pressure and/or volume, and conversely if temperature is increased, you will increase pressure and/or volume.
Required reading on Earth reaching a “tipping point” (a point of no return to a planet with which we are not familiar)- Washington Post Jan. 29, 2006
Clip of AIT on Roger Revelle and CO2 measurements.
Homework
to
prepare before Thursday (Sept. 6) will be sent out on class Listerve.
Sept. 6:
Quiz 1 handed back.
Records of Global Change
1) Global CO2 emissions. These are currently about 8,000 million metric tons of carbon [=8,000,000,000 tons C= 8 Gigatons(Gt C)= 8 billion tons C= 8 x 109 tons C)]. This CO2 comes from oil, coal, natural gas, “flaring” and cement manufacture.
These emission have increased since the beginning of the “Industrial Revolution” around 1800.
2) Atmospheric CO2. Direct CO2 measurements (“the most important graph of the 20th Century”), 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 385 ppm (part per million)- about 33% increase since 1958. The rate of increase has been variable over this time period, related to sources and sinks. Analysis of gas in ice cores tells us the pre-Industrial Revolution concentration of CO2 was about 280 ppm. Current concentration is the highest it has been in the last million years, but in geologic history there have been times when atmospheric CO2 has been much higher than today.
3) Sea ice. Current sea ice extent is the smallest of the record several decades long.
4) Retreat of glaciers world-wide.
5) Instrumental climate records.
The longest world-wide temperature records go
back to 1659 in
Examination of temperature
records from around the
(A) A site will have a “mean” temperature, but the actual average temperature from one year to the next is highly variable- In fact, rarely is the average temperature of any year equal to the mean of many years
(B) The trends of temperature at different sites are often not the same, and some stations may show an increasing temperature trends, but others show a decreasing trend.
(C) Depending on what part of the temperature record from a single station you look at, the trend may be different, even increasing in one time interval and decreasing in another.
(D)
Therefore
regional temperature mean trends (such as that for the
Sept. 11: Lecture notes shown in class are here. The geostrophic balance animation is here. The coriolis effect java applet is here. Tank experiment #1 is here. Tank Experiment #2 is here. Slides drawn in class are here. The activity we did in class is linked in the Syllabus/Schedule for this week. Sample Quiz 2 is also linked in the Syllabus/Schedule for this week.
Sept 13:
Lecture notes shown in class are here.
A link to the movie of high resolution ocean model output (from the
Navy HYCOM model) is here.
Link to Landsea (May 1, 2007 EOS)
on historical hurricane frequencies is here. Link to Holland (Sept
4, 2007 EOS) on changes in numbers of landfalling hurricanes is here. Link to Mann et al.
(Sept. 4, 2007 EOS) reply to Landsea's article is here.
Activities 3 and 5 handed back.
Fire alarm at about 20 minutes into class; we reassembled when alarm ended
US
“instrumental” temperature records of the last 120 years shows rising
temperature but not as steeply rising as global temperatures over that
period. The greatest rise seems to be at high latitudes, which
could have drastic consequences to Earth’s energy budget.
“Proxy” records of global change are used to estimate past climate (e.g., temperature or moisture)- tree rings, pollen, packrat middens, ice cores (high and low latitude), marine (ocean) and lake sediment cores (and microscopic shells), corals, speleothems (stalagmites), etc.
Earth has long history of warm and cool periods with the last 70 million years (since the demise of the dinosaurs) generally cool, but a series of alternating and very regular short interglacial (warm) periods and longer cold periods over the last 2 million years. The last interglacial period about 130 million years ago was warmer than the current interglacial.
Highest temperatures in last 180 million years estimated to have occurred about 120 million years ago when global temperature may have been at least 10C higher than present.
“Hockey stick” curve has been used to describe estimated temperature changes over the past 1000 years (slowly cooling from 1000 to 1900 and then rapid rise in temperature after 1900), but proxy records get fewer as we go back further during this time frame. Little Ice age corresponds to coolest conditions of the millennium (about 1500 to 1850AD), and Medieval Warm Period (about 1000AD)
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 action has an equal and opposite reaction (“conservation of
momentum” follows from this)
Law of Universal Gravitation- any and all objects exert a 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)
Sept. 20:
Quiz 2 handed back; Activity 6 (hydrologic cycle) was done at the end of class
Intro to water cycle (driven by solar energy)- reservoirs (or pools where water resides, represented by the amount [mass, volume] present), and fluxes (or flows/exchange processes represented by movement of water between reservoirs) Most water in ocean reservoir, most fresh water locked up in ice cap (and glacier) reservoir, more fresh water in groundwater than surface water (lakes and streams). Fluxes between water reservoirs, eg, runoff is the primary direct flux between continents and ocean, precipitation transfers water from atmosphere to land or ocean, evapotranspiration is the combination of evaporation from land and transpiration from land plants.
Streamflow can be measured with stream gage instruments back into the 20th Century, but tree rings can be used to reconstruct streamflow back hundreds of years.
Humidity in the atmospheric reservoir of the water cycle can be measured with a psycrometer, which has the bulb of one thermometer (the “wet-bulb thermometer”) covered with a moistened cloth. The larger the difference between the “dry-bulb” thermometer and “wet-bulb thermometer”, the lower the humidity in the air- WHY? (evaporation and cooling). Warmer air can “hold” more humidity- an increase in global temperature could result in more evaporation and more water vapor in the atmosphere, but relative humidity would not necessarily change because higher temps would mean more water-vapor holding capacity. Try USA Today and USA Today2 for more explanation. (TempCelsius = [TempFahrenheit – 32) x 5/9]
Pattern of latitude precipitation- highest at equator, and secondary peaks at about 45-55° latitude; minima at about 30° and 90° latitude (related to solar heating and general circulation)
With global temperature increase, the hydrologic cycle can be affected. Precipitation will change but not necessarily uniformly- in some places, more precipitation is forecast and others less. Where less, this could result in increasing incidence of drought such as conditions in the Dust Bowl of the 1930s.
Regions of the US have different circumstances with respect to population trends, water sources, and water quality, but the anticipated climate changes can influence many factors such as the amount of snowfall, retention of mountain snow and timing of melting, frequency of floods, etc.
In
the US
Southwest, the Colorado River system is a major source of water for 7
states
and
The
demise of
Lake Chad illustrates how climate change can be important in the face
of the
demands of a large, growing population (“
Oct. 2:
A
measure of the
amount of material dissolved in water is TDS (total dissolved solids)-
it
ranges from 0 parts per million (pure distilled water) to
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. Items inadvertently thrown in ocean can serve to inform us about ocean circulation.
Gulf
Stream
provides mild climate of British Isles and Scandinavia (compared to
more
extreme climate of
“Upwelling”
of nutrient-rich deep water along S. American coast supports food webs
(fisheries
along coastal
El Niño and currents in S. Pacific
El Niño tends to recur in irregularly from 2-7 years, and strength varies among events.
It
is related to
atmospheric and ocean circulation in the tropical
Evidence for El Niño events
Thick, 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
High precipitation in Ecuador/Peru; Low precipitation in Australia/Indonesia
During La Niña events conditions are opposite of those listed above.
“ENSO”
(El
Niño/Southern Oscillation)- during El Niño events, there
is increased
precipitation along
“Teleconnections”
are the influence of El Niño outside of the confines of the
El Niño has tended to be more frequent and stronger after the mid-1970s, whereas La Niña tended to dominate in the decades prior, suggesting some decadal periodicity; consequences of “El Niños of the Century” (1982-83 & 1997-98) in the western US (lower area burned, but in the next few years when there is La Niña the area burned is very large).
Exercise 8 involving improving your wording in formal writing.
Oct. 4:
More
writing
stuff; Remember, from now to the end of
the semester, improper use of “due to”, “since”, “while”,
or “that/which” on any formal writing activity (including
quizzes/mid-term/term
paper) will automatically result in a deduction of 5% of the total
value of the
exercise for each occurrence within the writing product.
Deep-ocean currents and the Ocean Conveyor Belt
Requires dense water to start cycle by sinking
Dense water achieved by (1) cooling or (2) increase in salinity through (2a) evaporation
or (2b) freezing
Salinity can be measured using electrical conductivity, because water with more ions (cations and anions) conducts electricity more readily than water with lower ionic concentration.
Densest water forms in far North Atlantic and far South Atlantic 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
Thermohaline circulation transports heat and salinity (salt) as nature tries to even out these imbalances around the world ocean.
There may have been times in the past, and maybe in the future, where the thermohaline circulation could slow or stop, with important climate consequences. Younger Dryas was an abrupt return to cold conditions about 12,000 years ago (10,000 radiocarbon years), 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 appears to have been teleconnected world-wide, probably by its influence on suppressing thermohaline circulation. This is an example of “abrupt climate change”
The story of tree rings and Younger Dryas in
central
Biosphere "biotic components"- trophic (nourishment) levels from bottom to top: (1)-primary producers=autotrophs; (2)-primary consumers=herbivores (=heterotrophs); (3)-secondary consumers=carnivores (also =heterotrophs) and additionally a group (4)-decomposers. “Omnivores” may eat at more than one trophic level.
These can be altered by global climate change or other influences/events. For example:
1. Change in species (abundance or composition; pioneering, invasion and extinction)
2. Change timing of species development or activity; loss of breeding habitat
3. Contribute to emigration or adaptive response
4. Catastrophic change- wildfire and frequency
Food
chains and
food webs:
90% loss of energy (and biomass) going from one trophic level to the next level above it. In other words, each trophic level has about 10 times the mass/energy as the trophic level above it.
Discussion of 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 (related to “climate” regions)
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) = GPP-respiration losses
Hawaiian CO2 curve and its wiggles representing photosynthesis (reduction of CO2) and respiration (increase in CO2) related to “seasonal biosphere” where there is big difference in winter and summer conditions. This occurs at high latitudes around the world, but most of the terrestrial plants at high latitudes are in the N. Hemisphere, so it shows the greatest “amplitude” of wiggles (difference between maximum and minimum in each wiggle). Colors of Life (seasonal greening of the world related to productivity)
Global Carbon Cycle- major reservoirs are the ocean, land plants and soils, and the atmosphere. Major fluxes are photosynthesis (from atmosphere to plants), respiration (from plants and soils to atmosphere), dissolution (from atmosphere to ocean) and evasion (from ocean to atmosphere). Fossil-fuel emissions are another flux (transferring CO2 from lithosphere to atmosphere) and although small relative to natural fluxes into the atmosphere, they are very important because the ocean and biosphere cannot take it all up, so atmospheric CO2 is rising.
Activity #9 on beef consumption and plant production needed to “grow” the beef being consumed, meat production and greenhouse gas emissions, fast food.
Oct. 18:
Midterm Exam handed back; add 7 adjustment points to your raw score to get the recorded score.
Review of question on Activity #9: it takes 10 times as much primary production (lowest trophic level; made up of plants) to support the herbivore trophic level, ie, it would take 400 pounds of grain to “grow” 40 pounds of beef.
Net primary productivity (NPP) = GPP(gross primary productivity) – respiration loss
Respiration loss is about ½ GPP
Aquatic: 125g d.m./m2/y to 2500g/ m2/y
(open ocean) (algal beds, reefs)
Terrestrial: 10g d.m./ m2/y to 300g/ m2/y to 400g/ m2/y
(desert) (tropical rain forests) (tropical wet lands)
(where “g d.m.” is grams of dry matter)
Coral reefs are like the “rain forests of the ocean” in terms of productivity. They are damaged or threatened by:
1) Hurricanes
2) Humans (excess nutrients, dynamite fishing, aquarium tropical fish trade, overfishing of starfish predators and algae and seaweed eating fish)
3) Change in environment (salinity, clarity, pH, temperature)
The pH change could be toward increasing acidity as more CO2 dissolves in the water (rising atmospheric CO2 concentrations)
The current dieback observed in coral reefs may be a result of several factors, often hard to isolate. Coral reefs may be reduced/killed by future warming of the ocean, but coral species are not equally susceptible to the conditions forcing coral bleaching, so the relative abundance of coral species may change and reefs may persist
Invasive species come from different locations, in many cases different contintents. Invasive species in US may be responsible for over $100 billion in losses each year. Examples:
Buffelgrass
(from
Africa, introduced to US in the 1940s) and cheatgrass (from
Zebra mussel were introduced into the Great Lakes from ship ballast in the 1980s, and are now spread throughout the Great Lakes and other nearby river systems including the Mississippi River. ZM’s are prolific filter feeders and filter fine organisms and particles out of the water, which removes the food for some fish species. Also, they encrust pipe taking up water and boats. Climate warming is expected to help them extend their range northward.
Change of Seasons- seasons may be shifting and expanding as a result of global warming.
Phenology is the study of timing of recurring biologic phases such as budbreak, flowering, first leaf unfolding, leaf fall, migration, hibernation, emergence, and breeding. Phenology can be linked to carbon and water cycling and energy of biosystems.
Lilacs in US appear to be flowering about 3-4 days earlier now than the first half of the 20th Century.
Growing season
in the
A US
Phenology network is coordinating and tabulating this information
for
several species, and other networks exist outside the
Activity #10, avoiding the use of “there is”, “there were”, “there are”, “there had been”, etc in writing.
In middle of class there was student survey regarding the class so far- instructors will get feedback.
Hypothetical logistic population growth curve stages=> 1. lag, 2. exponential, 3. stationary, 4. death (crash of population)
“Carrying capacity”= optimum population that can be sustained, and depends on natural resources (incl. food), energy, waste, interactions)
Plate tectonics and types of plate boundaries (plates colliding = “convergent” boundary; plates moving apart = “divergent” boundary; plates sliding past each other = “transform” boundary). Caused by convection (flow) in upper mantle. Contributes to lateral heterogeneous distribution of chemicals across the Earth’s surface. Boundaries associated with earthquakes and volcanoes.
In many cases, besides
earthquakes and
volcanoes, the location of ore
deposits of specific metals/elements is related
to plate tectonic and plate boundaries.
The richness of metal resources of a country is dictated by
their
current and past position with respect to plate tectonics ore-forming
processes, and other ore-forming processes such as related to climate. For example, western “porphyry” deposits
associated with former convergent plate boundaries have given the
Energy demand of world is now overwhelmingly met with fossil fuels; nuclear, hydropower, windpower, and direct solar power make only a small contribution to those demands.
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. World reserves of coal and oil would last about 125-200 years at current rate of usage. However, much lower reserves of oil compared to coal portend serious problems in the very near future. In the 1970s M. King Hubbert (petroleum geologist) predicted the world peak production of oil in the mid-1990s. Although it may be occurring now, or will occur within a few years, prices will subsequently spiral upward, and petroleum use is firmly entrenched in activities of world societies.
Activity 13, done as group discussing raw materials and energy aspects of common consumer goods.
Nov. 8:
Quiz 5 first 20 minutes; turn in Term Paper.
Some final thoughts on energy resources; A Crude Awakening and Peak Oil videos (2 min. each) (Full peak oil video, about 55 minutes)
Population and Resources- Forests and Deforestation:
Land-use changes (urbanization; conversion of land to grazing, agriculture; dedication of land to transportation [roads] or energy-flooding-resource concerns [dams/reservoirs])
Major mechanism of land-use change is deforestation
First forests in Devonian (about 400 my ago), but perhaps largest past forests were 300-350 my ago [Carboniferous], 40-100 my ago [Cretaceous]. evidence of which is found in coal beds. Although many of the tree species in the Earth’s early forests not longer exist, there are some descendants, many of which are diminutive in size.
Modern forests- 4-5 billion hectares world wide, estimates vary depending on definitions of forests and woodlands
40-50%
of
tropical forests (S. America, Asia, Africa) have been cut in last 200
years,
ie, very rapid deforestation (
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)
Tropical
forests
(India, Indonesia, Brazil have greatest deforestation; Japan, USA among
the
biggest importers of tropical wood); 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 our
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.
Fate could be linked to provisions of the
Deforestation (cont’d)
Deforestation
in
U.S.- Great Lakes forest fires of
Reading of account of human devastation in the aftermath of the Peshtigo fire.
Begin Soil degradation material with generalized statements on water and soil problems from the philosopher Jack Handy.
On-site costs (loss of nutrients and water) and off-site costs (sedimentation of rivers and lakes and adverse effects on aquatic organisms) of erosion in US might be $44B annually ($400B for whole world).
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.
Natural events impacting soils= floods,landslides,glaciers,wind,subsidence,drought,waves.
Anthropogenic acivities impacting soils= mining,agriculture,logging,dams,transportation, subsidence,wells.
Population and Waste
Radiative forcing by greenhouse gases- our understanding is “very high” that contributions to global warming by greenhouse gases have been important associated with inputs of CO2, CH4, and N2O. The “Global Warming Potential” (GWP) of methane (CH4) is about 20 times that of CO2 and the GWP of N2O is about 300 times that of CO2.
Anthropogenic sources of
CO2: industry, autos, land-use change/deforestation, wildfires and biomass burning
N2O: industry, autos, feedlots, fertilizers, wildfires and biomass burning
CH4: rice paddies, cattle, natural gas from wells and distribution system, natural gas from coal mines and landfills, wildfires and biomass burning.
Activity 14- group activity to (a) think of 6 alternative sources of energy other than fossil fuels, and which are related to solar (directly or indirectly) [for example, wind power is derived from solar energy causing differential heating of the Earth’s surface], and (b) come up with a 5-point plan to reduce GH gas emissions (2 points related to CO2, and the other 3 pts related to CH4 and N2O).
Nov. 15:
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
Despite the best intent of “The solution to pollution is dilution”, a build-up of air pollutants is favored by very stable atmospheric conditions (reducing vertical movement) associated with temperature inversions
Auto emissions usually check for particulates, unburned hydrocarbons (“HC” or VOCs), and CO; catalytic converters on automobiles are designed to convert CO to CO2, 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)
Natural sources exist for emission of nitrogen oxide, sulfur oxide, VOCs (such as terpene) and even ozone itself (lightning).
Acid rain (more properly “acid precipitation” or “acid deposition”)
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 5.6 (much more acid than neutral pH of 7), and sometimes other natural acids including organic acids can make the pH a little lower; thus rain from “clean” areas is slightly acidic); effects on “cultural heritage”, materials such as metals/marble, aquatic ecosystems, terrestrial systems.
“buffering"
(neutralization) of acid rain in carbonate terrain, whereas greatest
negative
impacts in granitic terrain such as the Northeast and
Even
if SO2
emissions were reduced, there are still large NOx emissions
across
the
Prospects
for
worldwide future emissions of NOx and SO2; “cap
and
trade” program of 1995 and its influence on SO2 emissions from
utilities in the
Stratospheric ozone- the “good” ozone (O3)is very effective in absorbing incoming UV; it is destroyed in reactions with Cl (freons, CFC)
A strong decrease in stratospheric ozone concentration above Antarctica has occurred since 1970; large increase in extent 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); Montreal Protocol in 1987 to stop manufacture and trade of CFCs and other chlorine-containing compounds
