R 15 The...

15 The Atmosphere C

HA

PT

ER

Charging Toward Cleaner Air in London

• More than 4000 people in London died during a “killer smog” event in 1952.

• In 2003, London started charging a fee to people who drove into the city during the week.

• Since the program began, traffic congestion in London has decreased by 30%, but there is not a lot of evidence that air quality has improved.

Talk About It What are the pros and cons of a

congestion-charging program?

Lesson 15.1 Earth’s Atmosphere

The air we breathe and all the weather we see is contained in the lowest 1% of the Earth’s atmosphere.

N2

NOT A GREENHOUSE GAS!!!

Non atmospheric nitrogen is part of some pollutants like NO2, N2O, or NO (NOx) which can cause smog, acid rain, or global warming

21% O2

78%

Properties of the Atmosphere

• Temperature: Varies

and location

• Pressure: In general,

air pressure decreases

with altitude; can be

measured using a

barometer.


Barometer

Relative Humidity

• The ratio of water vapor in air

to the maximum amount the

same air could contain at the

same temperature

• Is affected by temperature and

location; in general, warm air

holds more water.

• When air cools, water vapor

may condense to liquid (dew or

rain) or to ice (frost or snow).

Water vapor can only

condense on surfaces, such

as a petal or a dust particle.


Hoarfrost on leaves

Convection Currents

• Warm air is less dense than cool air.

• When air near the surface heats up, it rises; as it rises, it cools and then sinks.

• Rising and sinking fluids generate convection currents.

• Cause wind and heat to move through the atmosphere


QuickTime™ and a decompressor

are needed to see this picture.

Heat Transfer in the Troposphere


• Radiation: The

transfer of energy

through space,

such as heat from

the sun to Earth’s

atmosphere

• Conduction:

The transfer of

heat directly

between two

objects that are

in contact

• Convection: The

transfer of heat by

the movement of

currents within a

fluid (liquid or gas)

Layers of Atmosphere


• Troposphere: 0–11 km;

movement of air, weather

• Stratosphere: 11–50 km;

ozone layer, absorbs and

scatters UV rays

• Mesosphere: 50–80 km;

meteoroids burn up

• Thermosphere: 80+ km;

disturbances produce

aurora borealis

Did You Know? The stratosphere and mesosphere are cold, but the upper thermosphere can be hotter than 1500°C.

The earth is surrounded by

all kind of gases. This layer

is called the earth's

Atmosphere.

•Without this atmosphere

life on earth isn't possible.

It gives us air, water, heat,

and protects us against

harmful rays of the sun and

against meteorites.

•This layer around the earth

is a colorless, odorless,

tasteless 'sea' of gases,

water and fine dust.

•The atmosphere is made

up of different layers with

different qualities. It

consists of

•78 percent nitrogen,

•21 percent oxygen,

•0.93 percent argon,

•0.03 percent carbon

dioxide

The Sky Meets The Space

Fig. 18-3, p. 467

Atmospheric pressure (millibars)

0

Temperature 110

Thermosphere

65 100

1,000

90 55

80

70 Mesosphere 45

60 35

50

Alt

itu

de (

miles)

Alt

itu

de (

kilo

mete

rs)

40 Stratosphere

25

30

20 Ozone layer 15

10 Pressure

Troposphere 5

(Sea

level) –80 –40 0 40 80 120

Pressure =

1,000 millibars

at ground level

200 120 75

0

Temperature (˚C)

400 800 600

Thermosphere (52 – 300 miles)

Thinnest gas layer Where the space shuttle orbits Temp increases rapidly due to gamma rays, X rays, and

radiation hitting molecules and converting the kinetic energy to heat Molecules broken into ions by ejecting electrons – heated

by solar energy – causes ions to glow (aurora borealis – northern lights) Extremely high temps +3000 F – but because air so thin –

would feel cold since so few molecules contacting skin and transferring heat Radio waves reflected - makes communication possible

Aurora Borealis(in north) /Aurora

Australis(in south), a luminous

atmospheric phenomenon that

generally appear as bright colorful

bands of light commonly referred to

as the southern and northern lights,

occur in the ionosphere.

•Stratosphere

•Stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler higher up and warmer farther down.

•Almost completely free of clouds and weather

•Area where most long distance flights take place so they can avoid weather disturbances and take advantage of the strong and steady winds.

•Stratosphere (13-30 miles)

•Temperature increases with altitude because the ozone traps high energy radiation and holds heat.

•Ozone layer is found here –

•O3 formed by UV radiation and lightning

•Protects earth from UV radiation

•CFC’s caused “hole” over the poles seasonally – ozone layer is the thickest over the poles and thinnest over the equator

• Mesosphere (31-50 miles) • Temperature decreases with altitude.

• This is due to decreasing solar heating and increasing cooling by CO2 radiative emission.

• Coldest of all atmospheric layers – freezes water vapor into ice clouds

• Noctilucent clouds clouds visible after sunset

• Meteors burn up in this layer. Most melt or vaporize as a result of collisions with the gas particles contained there.

• The mesosphere lies above the maximum altitude for aircraft and below the minimum altitude for orbital space craft. As a result, it is the most poorly understood part of the atmosphere.

TROPOSPHERE

•0-7 miles

•75% of the mass of the atmosphere is found here

•Temperature decreases as altitude increases

•Convection currents redistribute heat and moisture around the globe

•Creates weather

•Greenhouse effect takes place here due to CO2 in the atmosphere.

Air Masses and Fronts

• Air masses: Large bodies of air with similar properties

• Fronts: Boundaries between air masses of different properties


Warm front

• Boundary along which a mass of warmer,

moister air pushes against a mass of

cooler, drier air

• Can produce light precipitation

Cold front

• Boundary along which a mass of cooler,

drier air pushes against a mass of

warmer, moister air

• Can produce heavy precipitation

Core Case Study: Different Climates Support Different Life Forms

• Climate -- long-term temperature and precipitation patterns – determines which plants and animals can live where

• Tropical: equator, intense sunlight

• Polar: poles, little sunlight

• Temperate: in-between tropical and polar

Solar Energy and Global Air Circulation: Distributing Heat

• Global air circulation is affected by the uneven heating of the earth’s surface by solar energy, seasonal changes in temperature and precipitation.

Figure 5-3

Fig. 5-3, p. 102

Spring

(sun aims directly

at equator)

Fall

(sun aims directly at equator)

Summer

(northern hemisphere

tilts toward sun)

Solar

radiation

23.5 °

Winter

(northern hemisphere

tilts away from sun)

Coriolis Effect Global air circulation is

affected by the rotation of the earth on its axis.

Figure 5-4

7-1 What Factors Influence Climate?

• Concept 7-1 Key factors that determine an area’s climate are incoming solar energy, the earth’s rotation, global patterns of air and water movement, gases in the atmosphere, and the earth’s surface features.

The Earth Has Many Different Climates (1)

• Weather • Temperature, precipitation, wind speed, cloud cover

• Hours to days

• Climate • Area’s general pattern of atmospheric conditions over decades and

longer

Fig. 7-2, p. 149

Natural Capital: Generalized Map of the Earth’s

Current Climate Zones

Fig. 7-2, p. 149

Polar (ice) Subarctic (snow) Cool temperate Highland Warm ocean current River

Warm temperate Dry Tropical Major upwelling

zones

Cold ocean current

Arctic

Circle

Tropic of

Cancer

Tropic of

Capricorn

Antarctic

Circle


• Air circulation in lower atmosphere due to 1. Uneven heating of the earth’s surface by sun

2. Rotation of the earth on its axis

3. Properties of air, water, and land

• Ocean currents • Prevailing winds

• Earth’s rotation

• Redistribution of heat from the sun

• Surface currents and deep currents

Fig. 7-3, p. 149

Global Air Circulation

Fig. 7-3, p. 149

Moist air rises,

cools, and releases

moisture as rain

Cold deserts

60°N Evergreen coniferous forest The highest solar

energy input is at

the equator. Hot desert

Northeast trades 30°N

Temperate deciduous forest and grassland

Westerlies

Air cools and

descends at lower

latitudes.

Tropical deciduous forest Warm air rises

and moves

toward the poles.

Solar

energy Equator 0°

Tropical rain forest

Tropical deciduous forest

Southeast trades Hot desert

30°S Westerlies

60°S

Cold deserts

Temperate deciduous forest and grassland

Air cools and

descends at

lower latitudes.

Polar cap

Polar cap

Fig. 7-4, p. 150

Cool,

dry air

Condensation and

precipitation

Heat released radiates to space

LOW

PRESSURE

HIGH

PRESSURE

Falls, is

compressed,

warms

Rises,

expands,

cools

Warm,

dry air

Hot,

wet air Flows toward low

pressure, picks up

moisture and heat

HIGH

PRESSURE Moist surface

warmed by sun

LOW

PRESSURE

Fig. 7-4, p. 150

Energy Transfer by Convection

in the Atmosphere

Fig. 7-5, p. 150

Connected Deep and Shallow Ocean Currents

Fig. 7-5, p. 150

Warm, less salty, shallow current

Cold, salty,

deep current


• El Niño-Southern Oscillation • Every few years

• Prevailing winds in tropical Pacific Ocean change direction

• Affects much of earth’s weather for 1-2 years

• Link between air circulation, ocean currents, and biomes

Figure 4, Supplement 7

Normal and El Niño Conditions

•El Niño is characterized

by warm temperatures,

and La Niña is

characterized by are

cooler temperatures in

the Eastern Pacific.

•Occurs when a change

in the direction of

tropical winds warms

the coastal surface

water, suppresses

upwelling, and alters

weather.

Figure 3 . World-wide climatic impacts of warm ENSO events

The upper half (3a)

corresponds to the

northern hemisphere winter

(October to March) and the

lower half (3b) covers

impacts during April to

September. D indicates

drought, R stands for

unusually high rainfall (not

necessarily unusually

intense rainfall) and W

indicates abnormally warm

periods. The figure is

modified from two

illustrations given by

Pacific Marine

Environmental Laboratory

WWW home page (NOAA,

USA).

Florida El Niño Effects

• Rainfall - Above average rainfall

• Severe Weather - During El Niño the jet stream is oriented from west to east over the northern Gulf of Mexico and Northern Florida. Thus this region is most susceptible to severe weather

• Temperatures - Below normal temperatures

• Winter Storms - Increased cyclogenesis (low pressure systems) in the Gulf of Mexico

• Hurricanes - El Niño almost always reduces the frequency of storms.

Florida La Niña Effects

• Rainfall -Generally dry conditions

prevail during La Niña's in late fall, winter and early spring.

• Wildfires - Increased risk of Wildfires in Spring/summer months.

• Temperatures - Temperatures average slightly above normal during La Niña events.

• Hurricanes - According to research, the chances for the continental U.S. and the Caribbean Islands to experience hurricane activity increases substantially during La Niña.

http://www.aoml.noaa.gov/hrd/Landsea/lanina/index.html

Drought in Southern Africa, Southern India, Sri Lanka,

Philippines, Indonesia, Australia, Southern Peru, Western

Bolivia, Mexico, Central America

Heavy rain and flooding in Bolivia, Ecuador, Northern

Peru, Cuba, U.S. Gulf States

Hurricanes in Tahiti, Hawaii

Reduced upwelling can adversely affect local bird

and fish populations off the coasts of Ecuador and

Peru.

Effects of El Nino http://www.usatoday.com/weather/resources/graphics/2008-09-25-el-nino-la-

nina-affect-us-weather_N.htm

http://www.usatoday.com/weather/resources/graphics/2008-09-25-el-nino-la-nina-affect-us-weather_N.htm



















Figure 5, Supplement 7

Impact of El Nino-Southern Oscillation

Greenhouse Gases Warm the Lower Atmosphere

• Greenhouse gases • H2O

• CO2

• CH4

• N2O

• Natural greenhouse effect

•Gases keep earth habitable

• Human-enhanced global warming

Fig. 3-4, p. 57

Flow of Energy to and from the Earth

Earth’s Surface Features Affect Local Climates

• Differential heat absorption by land and water • Land and sea breezes

• Rain shadow effect

•Most precipitation falls on the windward side of mountain ranges

•Deserts leeward

• Cities create microclimates

Fig. 7-6, p. 152

Rain Shadow Effect

Fig. 7-6, p. 152

Prevailing winds

pick up moisture

from an ocean.

On the windward side

of a mountain range,

air rises, cools, and

releases moisture.

On the leeward side of the

mountain range, air

descends, warms, and

releases little moisture,

causing rain shadow effect.

Microclimates – usually created around cities due to heat absorbing building materials like

concrete and brick. High buildings trap radiant heat and block wind flow. This can also

increase and trap pollution causing haze and smog.

URBAN HEAT ISLAND - REASONS

MOTOR

EXHAUSTS

FACTORY &

OTHER

POLLUTION

DOMESTIC HEATING DARK AND

DRY TARMAC

SURFACES

SMOG RESULTS

FROM POLLUTION

Human heat sources (domestic heating,

cars, factories) all warm the air.

Pollution by exhausts, factories and

other dusts absorb radiation and

prevent heat loss during the night. Dark

surfaces have a low albedo. Dry

surfaces reduce latent heat loss by

evaporation

In humid conditions, this may result in

smog (a mixture of fog and smoke)

which was common in pre-war London

and still is in LA, Rome, Athens,

Mexico City etc where surrounding

hills prevent the escape of polluted air.

RUSH

HOUR

TRAFFIC

THROUGH

A HAZE OF

FUMES

Are living / green roofs the solution?

• can help act as insulation

• promote cooling in cities

• can be used as an urban garden to grow crops or

small amounts of food for a community

Lesson 15.2 Pollution of the Atmosphere

Air pollution is estimated to cause 2 million premature deaths worldwide every year.

Sources of Air Pollution

Lesson 15.2 Biomes

• Natural processes: Windblown dust, particles in volcanic

eruptions, smoke and soot from fire

• Human sources: Most come directly or indirectly from

the burning of fossil fuels.

Did You Know? Humans can increase the hazards of natural air pollution. For example, by removing trees, humans expose soil, which can dry out and add to huge dust storms when picked up by wind.

Dust storm approaching a U.S. farm during the 1930s

Types of Air Pollutants


• Primary air pollutants:

Released directly into the

atmosphere; example: soot

• Secondary air pollutants:

Formed when primary

pollutants react chemically

with other substances;

example: sulfuric acid

Sources and Types of Air Pollutants

Fig. 18-5, p. 469

METHANE (VOC)

• Agricultural sources

• Cows

• Rice paddies

• Energy Related

• Landfills

• Oil recovery/drilling

• Liquid used for industrial purposes

• offgassing

Rice paddies are one

of the largest man-

made sources of

methane, and rice is

the world’s second-

most produced staple

crop.

As more carbon

dioxide enters the

atmosphere, rice

plants grow faster, the

experimental data

showed. This growth,

in turn, pumps up the

metabolism of

methane-producing

microscopic

organisms that live in

the soil beneath rice

paddies. The end

result: More methane.

Methane and

permafrost • https://www.youtube.com/wat

ch?v=2w4UQfJHD-A

https://www.youtube.com/watch?v=2w4UQfJHD-A




How Air Pollutants Affect Your Health


• Lung irritation and respiratory

illnesses, such as asthma

• Carbon monoxide interferes with

body’s ability to use oxygen.

• Trace amounts of some air

pollutants, such as benzene or

soot, may contribute to cancer.

How Pollutants Are Formed from Burning Coal and Oil, Leading to Industrial Smog

Fig. 18-9, p. 474

Smog


• A mix of air pollutants that forms over cities

• “Smog” is a combination of the words smoke and fog.

• Industrial smog (soot, sulfur, and water vapor) comes from

industrial sources. GREY smog

• Photochemical smog is mostly tropospheric ozone created

when primary pollutants from vehicle exhaust react to

sunlight. BROWN CLOUDS

Charging Toward Cleaner Air in London

• More than 4000 people in London died during a “killer smog” event in 1952.

• In 2003, London started charging a fee to people who drove into the city during the week.

• Since the program began, traffic congestion in London has decreased by 30%, but there is not a lot of evidence that air quality has improved.

Talk About It What are the pros and cons of a

congestion-charging program?

• Normally, air near Earth’s surface warms and rises, carrying pollutants with it.

• When a layer of warmer air sits over a layer of cooler air, it traps pollution near Earth’s surface.

Temperature Inversions Lesson 15.2 Pollution of the Atmosphere

Did You Know? A

thermal inversion

caused London’s

“killer smog.”

QuickTime™ and a decompressor


Acid Deposition Lesson 15.2 Pollution of the Atmosphere

• Sulfur dioxide and nitrogen oxides can react with water,

oxygen, and other chemicals to form acids.

• Acid falls as particles or dissolves in precipitation, lowering the

pH of rain and snow.

• Acid deposition harms forest and lakes and damages human

structures.

Did You Know? Rainwater

is naturally acidic (pH 5.6),

but acid precipitation in

some parts of the U.S. has

a pH as low as 4.

For humans, touching or

walking in acid rain is not

harmful BUT the acidity

can dissolve heavy

metals and other

compounds that can

cause injury to humans

that may come into

contact with

contaminated water or

soil.

Lesson 15.3 Controlling Air Pollution

Since the Clean Air Act was first enacted in 1963, emissions of the worst pollutants in the U.S. have decreased by 57%.

The Clean Air Act


• First passed in 1963 to protect

human and environmental health

by improving air quality; has been

revised several times

• Limits emissions of pollutants

• Sets standards for air quality,

• Establishes a legal framework for

suing industries that break the

rules, and provides funding for

pollution control

CAFÉ Standards

•Corporate average fuel economy

•An effort to reduce fuel consumption and emissions

•Avg mpg efficiency of 27.5 (cars) 22.5 (suv and trucks) – 2010 standards

The Background

On May 19, 2009, President Barack Obama proposed a new national fuel economy program which adopts uniform federal standards to regulate both fuel economy and greenhouse gas emissions while preserving the legal authorities of DOT, EPA and California. The program covers model year 2012 to model year 2016 and ultimately requires an average fuel economy standard of 35.5 miles per US gallon (6.63 L/100 km; 42.6 mpg-imp) in 2016 (of 39 miles per gallon for cars and 30 mpg for trucks), a jump from the current average for all vehicles of 25 miles per gallon.

The Argument

The evidence is overwhelming that CAFE standards result in

more highway deaths. A 1999 USA TODAY analysis of crash

data and estimates from the National Highway Traffic Safety

Administration and the Insurance Institute for Highway Safety

found that, in the years since CAFE standards were mandated

under the Energy Policy and Conservation Act of 1975, about

46,000 people have died in crashes that they would have

survived if they had been traveling in bigger, heavier cars

Major Accomplishments of the Clean Air Act


• Catalytic converters, present in all

cars since 1975, have reduced

vehicle emissions.

• Lead has been phased out of gasoline.

• Industries and power plants have reduced releases of

pollutants by using scrubbers, which remove or alter

chemicals before they leave factory smokestacks.

Did You Know? The removal of lead from gasoline has led to a 99% reduction in lead emissions since 1973.

We Can Use the Marketplace to Reduce Outdoor Air Pollution

• Emission trading or cap-and-trade program • https://www.youtube.com/watch?v=EKT_ac4LPkU

• https://www.youtube.com/watch?v=axr95YXuxPE

• Mixed reactions to program

• SO2 emissions down significantly

• NOx now in effect

• Mercury plan strongly opposed for creating toxic hotspots

• Many problems with making cap-and-trade effective

https://www.youtube.com/watch?v=EKT_ac4LPkU

https://www.youtube.com/watch?v=axr95YXuxPE

The Ozone Hole


• Ozone is a pollutant in the troposphere,

but in the stratosphere it creates a

protective barrier against UV radiation.

• Chemicals called chlorofluorocarbons

(CFC), which used to be found in

everything from aerosol cans to

refrigerators, have destroyed ozone,

causing an “ozone hole” to form over

Antarctica.

• An ozone hole allows more UV

radiation to reach Earth’s surface,

potentially increasing cases of skin

cancer.

Recovery of the Ozone Layer


• The Montreal Protocol is an international treaty signed in

1987 that has cut CFC production by 95% since the 1980s.

• Ozone levels in the stratosphere have begun to stabilize,

and the ozone hole will likely start to disappear….?????

Ozone Hole 2000

QuickTime™ and aTIFF (Uncompressed) decompressor


The Antarctic ozone hole, which

was expected to reduce in size

swiftly when manmade chlorine

emissions were outlawed 27

years ago, is stubbornly

remaining the size of North

America, new data from Nasa

suggests.

Natural Capital Degradation: Effects of Ozone Depletion

Fig. 19-22, p. 522

What Role Do the Oceans Play in Projected Climate Disruption?

• Solubility of CO2 in ocean water

• Warmer oceans • Last century: 0.32-0.67C°increase

• Absorb less CO2 and hasten atmospheric warming

• CO2 levels increasing acidity

• Affect phytoplankton and other organisms

There Is Uncertainty about the Effects of Cloud Cover on Global Warming

• Warmer temperatures create more clouds • Thick, low altitude cumulus clouds: decrease surface temperature

• Thin, cirrus clouds at high altitudes: increase surface temperature

• Effect of jet contrails on climate temperature

Enhanced Atmospheric Warming Could Have Serious Consequences

• Worst-case scenarios • Ecosystems collapsing

• Low-lying cities flooded

• Wildfires in forests

• Prolonged droughts

• More destructive storms

• Glaciers shrinking; rivers drying up

• Extinction of up to half the world’s species

• Spread of tropical infectious diseases

Permafrost Is Likely to Melt: Another Dangerous Scenario

• If permafrost in Arctic region melts • Methane, a greenhouse gas, will be released into the atmosphere

• Arctic permafrost contains 50-60x the amount of carbon dioxide emitted annually from burning fossil fuels

• Methane in permafrost on Arctic Sea floor

Sea Levels Are Rising (1)

• 0.8-2 meters by 2100

• Expansion of warm water

• Melting of land-based ice

• What about Greenland?

Agriculture Could Face an Overall Decline

• Regions of farming may shift • Decrease in tropical and subtropical areas

• Increase in northern latitudes

• Less productivity; soil not as fertile

• Hundreds of millions of people could face starvation and malnutrition

Fig. 19-16, p. 513

Collect Greenhouse Gas Emissions and Stash Them Somewhere

• Solutions 1. Massive global tree planting; how many?

2. Restore wetlands that have been drained for farming

3. Plant fast-growing perennials on degraded land

4. Preserve and restore natural forests

5. Promote biochar

6. Seed oceans with iron to stimulate growth of phytoplankton

7. Carbon capture and storage – from coal-burning plants

Governments Can Help Reduce the Threat of Climate Disruption

1. Strictly regulate CO2 and CH4 as pollutants

2. Carbon tax on fossil fuels

3. Cap-and-trade approach

4. Increase subsidies to encourage use of energy-efficient technology

5. Technology transfer

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