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Weather and Climate

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Title: Weather and Climate


1
Weather and Climate
  • Lecture 5 May 2008
  • Global Climate Change
  • Pollution

2
The Iron Hypothesis
3
Vast stretches of ocean are barren
  • Plenty of Nitrogen
  • Plenty of Phosphorus
  • Plenty of sun
  • Whats Missing?
  • IRON
  • Add iron to water, phytoplankton bloom will
    consume plenty of carbon

4
The experiment was vigorously opposed
  • It was a testable hypothesis
  • Geritol solution
  • Hazardous manipulation of the environment
  • Removes carbon from environment, trapping it in
    the ocean this idea was embraced by
    corporations and some countries to meet Kyoto
    protocols
  • Might cause algal blooms and methane release

5
Ironex I II
  • Ironex I 445 kg of iron dumped into ocean near
    the Galapos (64 km2 clear blue ocean)
  • Phytoplankton levels tripled
  • Ironex II spinkled iron into same ocean area
    several times over a period of three days.
  • Phytoplankton increased 30x
  • Produced same biomass as 30 redwood trees
  • Sequestered 2500 tons of carbon

6
Thermohaline Circulation
  • A global conveyor belt in the ocean, by which
    water moves great distances horizontally and
    vertically
  • Driven by density changes caused by cooling water
    (which makes water denser) and evaporating (which
    makes water saltier and denser)

7
Dense water in the ocean is...
  • Very cold
  • Very salty -- rain makes seawater lighter
    (fresher)

8
(No Transcript)
9
Thermohaline Circulation
  • Warm water flows north in Gulf Stream, and
    experiences strong evaporation and cooling (makes
    water saltier and colder)
  • Dense water sinks near Greenland, flows south
    through Atlantic towards Antarctica
  • Water also sinks near Antarctica
  • There are just two sources of deep water!

10
Thermohaline circulation
  • Deep water has lots of oxygen near Labrador Sea,
    and near Antarctica
  • Deep water has less oxygen in the Pacific --
    biological activity consumes oxygen as the water
    moves along

11
Thermohaline circulation
  • Why no sinking in N. Pacific?
  • Pacific Ocean waters are fresher (less salty)
    than the Atlantic, therefore less dense! Harder
    to sink
  • The deep water slowly warms and rises (over
    years!) and then returns to the north Atlantic to
    sink again

12
How to shut off Thermohaline?
  • Warm up North Atlantic/Arctic Ocean
  • Make a cheesy Jake Gyllenhaal movie
  • Put fresh water over the North Atlantic
  • Lots of Precipitation
  • Lots of Glacial melt

13
Ozone
  • Beneficial molecule in the stratosphere
  • Absorbs harmful UV radiation
  • Responsible for stratospheric temperature
    inversion
  • How is ozone formed?
  • O2 hv -gt O O (1)
  • O O2 -gt O3 (2)
  • O3 hv -gt O2 O (3)
  • O O2 -gt O3
  • O O3 -gt O2 O2 (4)

hv is energy from the sun
Ozone eventually returns to regular oxygen
molecule
14
Stratospheric Inversion
  • Helps put a cap on top of tropospheric mixing
  • Unique to Earth

15
Stratospheric Ozone Hole
  • First noticed in 1970s by surface based and
    space-based monitors, centered on South Pole
  • British Antarctic Survey
  • TOMS TOTAL OZONE MAPPING SPECTROMETER satellite
    -- measures ozone data from back-scattered UV
    sunlight (no data available during Antarctic
    winter)
  • Readings initially thought erroneous

16
Big changes as time evolves!
17
What caused Ozone destruction?
  • Catalytic reaction with Chloroflourocarbons --
    especially in the presence of ice.
  • During Antarctic night, no sunlight to produce
    ozone
  • Over Antarctica, air is isolated during winter
    because of circular vortex -- rare to replenish
    with ozone-rich air from lower latitudes.

18
CFCs
  • Refrigerants
  • Were popular because they were thought to be
    chemically inert
  • CFCs slowly diffuse upwards and reach
    stratosphere
  • UV light in stratosphere breaks down CFCs
  • Chlorine atoms react with Ozone molecules

19
Chlorine in the stratosphere
  • During polar night, chlorine atoms are liberated
    from HCl and ClONO2 on cold clouds. (Converted to
    more active forms Cl2
  • Heterogeneous reaction that occurs on a surface
    -- and it happens rapidly!
  • Originally thought there were no surfaces in the
    stratosphere for this to occur on, but because
    its so cold, ice clouds will form

20
What happens when the sun rises?
  • Cl2 split apart by sunlight to two Cl atoms
  • Then
  • ClO ClO M -gt Cl2O2 M  
  • Cl2O2 hv -gt Cl ClO2  
  • ClO2 M -gt Cl O2 M 
  • then 2 x (Cl O3) -gt 2 x (ClO O2)   
  • net 2 O3 -gt 3 O2 -- and the ClO can then react
    with more ozone

21
Summary
  • The polar winter leads to the formation of the
    polar vortex which isolates the air within it.
  • Cold temperatures form inside the vortex cold
    enough for the formation of Polar Stratospheric
    Clouds (PSCs). As the vortex air is isolated, the
    cold temperatures and the PSCs persist.
  • Once the PSCs form, heterogeneous reactions take
    place and convert the inactive chlorine and
    bromine reservoirs to more active forms of
    chlorine and bromine.
  • No ozone loss occurs until sunlight returns to
    the air inside the polar vortex and allows the
    production of active chlorine and initiates the
    catalytic ozone destruction cycles. Ozone loss is
    rapid. The ozone hole currently covers a
    geographic region a little bigger than Antarctica
    and extends nearly 10km in altitude in the lower
    stratosphere.

22
Montreal Protocols 1987
  • Reduce/eliminate CFCs by 2010, replace with more
    chemically inert species, or more chemically
    reactive species so they rain out in troposphere
  • CFC accumulation is declining, but it takes up to
    100 years to remove Cl atoms from stratosphere
  • CFCs are also a powerful greenhouse gas

23
Carbon Dioxide in the atmosphere
  • Concentrations are rising because of fossil fuel
    use
  • Important greenhouse gas
  • Vital for plant growth

24
How do we know CO2 is from fuel?
  • Radiocarbon dating -- carbon in fossil fuels
    lacks radioactive carbon because it is so old -
    Roger Revelle
  • 1957 First publication
  • 1965 Presidential Advisory Panel
  • 1977 National Academy of Sciences Panel found
    40 of anthropogenic carbon stayed in the
    atmosphere

25
Where does the rest of CO2 go?
  • Ocean absorbs much of it, but more slowly than
    emitted on land -- takes about a decade to absorb
    the typical molecule (and it stays there for
    several 100 years, which is how long it takes the
    ocean to overturn)

26
Why is CO2 important
  • Top Line CO2 concentration
  • Bottom Line temperature inferred from deuterium
    concentration
  • Source Vostok Ice core (to 150000 years BP)

27
What controls a locales climate?
  • Short answer the weather
  • Latitude
  • Altitude
  • Position relative to water
  • Prevailing wind direction (where does the place
    sit with respect to the General Circulation?)

28
Note change in climate with height
29
Koeppen Climate Classification
30
East side of Continents
  • Humid, warm Affected by circulation around
    subtropical High, which circulation moves warm,
    moist air poleward
  • China
  • eastern US
  • eastern South America
  • eastern Australia

31
West side of Continents
  • Humid, cool Affected by west-east motion of
    airmasses off upstream ocean … unless the motion
    is blocked by mountains
  • Europe
  • coastal Pacific Northwest
  • coastal western South America
  • southwestern Australia

32
San Francisco, Wichita, and Norfolk are all at
the same latitude, and about the same
altitude. Do they enjoy the same climate?
33
Cities far from the moderating effects of the
ocean show greater temperature swings
during the year! They have higher Continentality
34
This is also true of Extreme Temperatures
  • Which states have record highs exceeding 120 F?
  • California (134)
  • Arizona (127)
  • Nevada (122)
  • Kansas (121)
  • North Dakota (121)
  • Which states have record highs below 110 F?
  • All border the ocean (except Vermont)
  • Only 109 F in FL!

35
Which places are HOT
  • Low altitudes (Death Valley)
  • Away from ocean (North Dakota)
  • Sunny (downward motion in General Circulation)
  • Dry regions -- not a lot of precipitation, so no
    need for a lot of evaporation

36
Which places are COLD
  • High altitudes
  • Away from ocean (North Dakota)
  • Clear (allow radiational cooling)
  • Dry regions -- not a heat content
  • Far from equator (more energy input into Earth
    system at the Equator)

37
Which places are DRY
  • Very cold regions (saturation vapor pressure will
    be very low)
  • Away from ocean
  • Leeward side of mountains
  • Downwelling branch of General Circulation (Hadley
    Cell)

38
Which places are WET
  • In the ITCZ -- plenty of moisture, upward motion
  • Near the Polar Front
  • Windward side of mountains
  • Downwind of moisture sources (ocean)

39
What are ways WI climate could be altered?
  • Build an east-west Rockies-type mountain range
    from North Carolina to Colorado
  • No more moisture from Gulf of Mexico
  • South winds downslope/warming
  • Cold air couldnt sweep south
  • North winds moving up into mountains would
    deposit any moisture they had

40
What are ways WI climate could be altered?
  • Build an east-west Rockies-type mountain range
    along the US-Canada border
  • Still get moisture from Gulf of Mexico
  • Much warmer in winter -- cold airmasses would be
    unable to move over the mountains
  • North wind downslope wind with warming

41
What are ways WI climate could be altered?
  • Gulf of Mexico moves north, flooding TX/OK/KS
  • More moisture/warmth available year round with a
    south wind
  • More plentiful snows
  • Increased threat from hurricanes in summer

42
What are ways WI climate could be altered?
  • Remove Rocky Mountains
  • Mild, moist air from Pacific could penetrate
    farther inland in winter
  • More difficult to generate cP air in winter
    because mountains would not block flow
  • Mountains help lock in flow patterns

43
How is Earth affected by Mountains?
  • Higher altitudes are colder
  • Plentiful snows will increase the albedo
  • Temperature decreases with height
  • Mountains divert west-east flow
  • Air can stagnate and become very cold
  • Warm/Wet on windward side
  • Cold/dry on leeward side
  • A flat Earth is a warmer Earth

44
What kind of cloud?
45
What kind of cloud?
46
Air Pollution
  • Not all pollution is anthropogenic (i.e.,
    man-made). Choking gases can also come from
    volcanoes and sea vents
  • Air pollution effects are magnified when areas
  • have light winds (little or no horizontal mixing)
  • under inversions (little or no vertical mixing)

What kind of feature has light winds and
inversions?
47
Smog
  • Term coined by London physician Harold Des Voeux
    in 1911 -- a combination fog and smoke.

48
The solution to pollution is dilution
That is, the short-term solution to an immediate
problem
49
There are some very famous pollution episodes
  • Donora, Pennsylvania in October 1948
  • London, England in December 1952

50
Donora, Pennsylvania
  • Inversion under a High Pressure System (warm air
    aloft, little vertical mixing)
  • Weak horizontal winds associated with High
    pressure

51
Donora Pennsylvania
H
Donora is in a valley along the Monongahela River
southeast of Pittsburgh
52
Donora, Pennsylvania October 1948
  • That smoke puts bread on my table
  • Killed about 20 people (primarily those with
    pre-existing respiratory problems)
  • American Steel and Wire Company
  • Donora Zinc Works -- zinc and iron works
  • Lots of Sulfur Dioxide emissions mixed with fog
    to yield sulfuric acid fog
  • Persisted Friday-Sunday, then it rained
  • Conspiracy theorists killed by flouride

53
Why not in Pittsburgh?
  • Just started cutting back using bituminous coal
    as a power source for Steel works
  • Just started a smoke control ordinance
  • Walter Winchell reported from Donora, and it
    gained national infamy
  • Donora (and others) lead to Clear Air Act (1970)

54
Whats the difference between smog in Donora in
1948 and in LA of Houston today?
  • Smog in Donora a mix of fog and SO2 -- led to
    sulfuric acid mist (ouch!)
  • Smog today -- ozone, Nitrogen oxides, volatile
    compounds
  • Today smog causes different types of health
    problems

55
Fog in 1952
Light surface winds, an inversion aloft
56
London in December 1952
  • Spell of cold weather -- lots of coal burned for
    heat -- lots of dirty smoke
  • Inversion developed at night on the 5th/6th
  • Visibility lt50 m for more than 2 days!
  • Thousands of tons of black soot and sulfur
    dioxide particles from coal burnt for heat
  • weight of smoke (mg/m3) increased 5-10x
  • SO2 concentration increased up to 10 fold

57
(No Transcript)
58
London England 1952
From a book People…found their way along the
sidewalks by feeling the walls of buildings
59
What was in smog?
  • 1000 tons of smoke particles
  • 2000 tons of Carbon Dioxide
  • 140 tons of hydrochloric acid
  • 14 tons of flourine
  • 370 tons of sulfur dioxide converted to 800 tons
    of sulfuric acid

60
How did Fog kill?
  • Bronchitis/asthma suffers suffocated as they
    wheeze to death
  • Congestive heart failure -- lack of oxygen makes
    heart work harder -- leads to cardiac arrest
  • ozone causes permanent lung damage -- other
    contaminants damage respiratory cells, cause lung
    inflammation
  • Week before 2000 died.
  • Week of fog 4000 died

61
Fog as a Killer
Death rates rose most for 45-64 year-olds 2/3rd
s of those who died were gt 65.
62
When did the Fog lift?
  • 10 December -- after 5 days -- winds shifted to
    west and blew the fog out down the Thames and out
    to sea.
  • Probably more vertical mixing as the weather
    regime shifted, so pollutants moved higher into
    the atmosphere as well
  • During the episode, pollutants were confined to
    the boundary layer

63
Other famous pollution problems
Houston, Texas
Causes Automobiles, Petrochemical
plants Aggravations Sea breeze/land breeze
circulation Stagnant weather for much of summer
-- no change in airmass
64
Houston pollution from satellite
Convert difference in downward looks and fore/aft
looks to particulate density (optical depth)
65
Denvers Brown Cloud
Sources Automobiles, wood-burning stoves big
improvements since early 1980s
Periodic inversions trap air below mountain tops
66
Los Angeles
  • Sited in a basin
  • Downstream of Pacific High (downward motion, and
    an inversion)
  • Difficult to ventilate -- pollutants get trapped
    in sea/land breeze circulation
  • Lots of cars!

67
Mexico City
7500 above sea level
24,000,000 people
View From Space Shuttle
68
Beijing
New Delhi
The persistent haze is a pungent mixture of
wood, coal, and cow-dung smoke, with generous
contributions from diesel auto, bus, and truck
exhaust, and from the ubiquitous gas/oil-burning
scooters and rickshaws
69
Why do inversions promote pollution?
70
Pollution distribution in vertical controlled by
the stability
Difficult for particles to move in the vertical
Particles easily move in the vertical
Particles easily move to the surface, but dont
move aloft
71
Pollution Mitigation
  • Make smoke stacks very tall!
  • Stack output into inversion layer, above the
    unstable boundary layer
  • Site smokestack in a region where drainage winds
    will remove pollution -- or where youre far from
    population
  • Put your powerplants somewhere besides downtown!

72
Other effects of pollution
  • Adds cloud condensation nuclei to air
  • Fox River Valley cloudiness from extra CCN from
    paper plants (more fog?) -- ditto Tyrone PA in
    the 1960s
  • Heat source at smokestack, so cumulus cloud at
    the top of smoke plume
  • If you live on a lake, pollutants can get trapped
    in Lake Breeze and never ventilate.

73
Main pollution sources
  • Mercury and sulfur from coal-burning power
    plants
  • Smoke from forest fires can cause pollution over
    very large areas
  • Carbon Monoxide, Nitrous Oxides from vehicles

74
Alaska had many fires in 2004
75
Visible from space
76
In the infrared channels too!
Dark Pixels are very warm (fire)
77
Acid Rain
  • Acid Rain is mostly caused by SO2 and NOx
  • 2/3 of SO2 from coal-fired power plants
  • 1/4 of NOx from coal-fired power plants
  • Pure rainwater has pH of 5.5
  • pure water pH of 7
  • Acid rain pH of 4.3
  • pH down to 2.5 observed (Mt Tsukuba, 1984)

78
(No Transcript)
79
Effects of Acid Rain
  • Increased mortality in aquatic species…chart at
    right shows that some are more tolerant of acid
    than others
  • Effects tempered by local geography, especially
    limestone

80
Effects of Acid Rain
  • Increased nitrogen deposition in water leads to
    algal blooms
  • Damages leaves, and weakens trees
  • Weakens paint on cars
  • Erodes marble in buildings

81
More on Acid Rain
Trees die from the top down (spruce, sugar maple )
Deforestation in Germany 1970 and 1985 images
82
Acid Rain weakens and then something else kills
the tree
  • Ice Storm
  • Persistent drought
  • Too much water

83
Pollution Modeling
  • Use numerical models to tell where the pollutants
    from a stack will end up
  • Employs many meteorologists!
  • Fundamentals of Stack Gas Dispersion
  • buoyant smoke plume rise
  • Gaussian modeling theory
  • Local meteorological observations
  • very realistic topography
  • interaction between microscale and mesoscale

84
Changing the Climate
  • Climate naturally changes due to changes in solar
    forcing (Milankovitch Cycles).
  • Feedbacks can amplify any change

85
Iron can cause Climate Change!
  • Expand desert areas more likely to get dust
    storms
  • Dust includes iron, which is transported to the
    ocean, fertilizing it for phytoplankton
  • Plankton blooms remove carbon from atmosphere,
    and store it in ocean (confirmed in 2002 field
    experiment SOFEX)
  • CO2 removal leads to temperature drop
  • Whats missing a brake on the cooling!

86
Other trace gases impact the climate
  • Dimethyl sulfide (DMS)
  • Gas produced by phytoplankton
  • Acts as a cloud condensation nucleus
  • Enhanced production as temperature increases
  • More CCN with warmer temperatures, more clouds
    and albedo increases, Earth temperature drops
  • Puts the brakes on warming

87
Snow Affects the climate!
Snow-Albedo feedbacks
88
View from GOES West
89
Did this affect the temperature?
2.5 snow in MKE
90
Same Thing This Winter
  • Clear, calm night, temperature falls to the
    dewpoint
  • Clear, calm night, temperature falls to below the
    dewpoint

Which event has snow on the ground?
91
How does snow cool? Remember these?
  • Incoming solar radiation reflected back to space
  • Insulate bottom of atmosphere from warm
    underlying surface
  • Cool down more rapidly at night snow is a great
    emitter!
  • Also, fresh snowcover has a HUGE surface area

92
Why is snow darker over a city?
  • Note that Chicago is not as white
  • Urban Heat Island -- maybe less snow fell
  • City is a very dirty place -- snow rapidly gets
    sooty
  • Albedo effects reduced over the city
  • More shadows?

93
Todays Topic Global Warming
  • Is the Earth getting warmer?
  • YES!

94
How to tell what temperature was?
  • Examine sediments and soil deposits
  • Heavy water more common when glaciation
    preferentially removes light water from the
    ocean/lakes.
  • Pollen in ice cores, sediments
  • Deuterium in ice cores
  • Heavy hydrogen more common when its cold
  • Tree Rings
  • Need to know what T was if youre trying to
    figure out how its changing

95
Today 385 ppmv
Extract dissolved CO2 from ice cores, compare to
heavy water
96
Note on the previous slide
  • Temperature increases, then CO2 increases
  • Likely cause warmed ocean releases CO2
  • CO2 has increased before temperature in the past
    200 years this behavior is different than in
    the past
  • The historical record shows that temperature
    increases, then the CO2 increases, then the
    temperature drops

97
What does past T record tell us?
  • Earth is now warmer than its been -- were
    emerging from a Glacial period
  • Warming started about 18K years ago
  • Period of cooling between 14K and 10K years ago,
    then renewed warming

Younger-Dryas
98
Younger-Dryas
  • Melting Glacier flooded North Atlantic, capping
    the ocean with fresh water, shutting off the
    Thermohaline circulation

99
(No Transcript)
100
Feedbacks can amplify change
  • Remove snow albedo drops, Earth warms
  • Add vapor, Greenhouse forcing increases, warms
    Earth so more water evaporates …
  • Plants die from drought, air is drier because of
    reduced evapotranspiration

101
Feedback can damp change
  • Add vapor, more clouds will form, shading Earth
    and causing cooling
  • Warm the Earth, and it emits more energy, causing
    cooling (and the amount emitted varies as T4)

(Stefan-Boltzmann Equation)
102
From Last time Mountains
  • Cause preferred flow regimes
  • Block mild air from penetrating to center of
    Continents…cP air can form unimpeded
  • Also, if land at poles, more likely to have
    glaciers there, which increases the Earths albedo

103
Politics of Global Warming
  • Some entities have a vested interest in the
    status quo -- government-mandated restrictions
    related to Global Warming reduce profitability
  • Politicization of science does little to advance
    true understanding

104
Model Studies of Global Warming
  • Most studies suggest that warming is concentrated
    at the Poles
  • Can model, if run backwards, predict the past
    climate? (Usually, no is that a reason to
    ignore model results?)

105
Climate Change is natural
This time series suggests the Earth should be
cooling!
106
What causes the regular pulses in temperature?
  • Milankovitch forcing
  • Changes in orbital parameters -- three different
    effects
  • Change in time of perihelion/aphelion
    (Precession of the Equinox)
  • Change in ellipticity of orbit
  • Change in Inclination (Obliquity)

107
Precession of the Equinox
  • Perihelion occurs about 5 January.
  • Changes with time -- regresses 1 day every 58
    years.
  • Period is 21000 years
  • In 21000 years, perihelion will be 5 January
  • in 10500 year, perihelion will be 5 July
  • Snowier in northern Hemisphere when its warmer
    -- more likely that snow will persist through the
    summer (and become a glacier)
  • More snow reduces Earths temperature through
    albedo affect
  • Effects in Northern Hemisphere dominate because
    theres more land in the northern Hemisphere

108
Changes in ellipticity
  • Varies from nearly circular to 3x as elliptic as
    now with a period of 100,000 years
  • Eccentricity varies between 0 and 0.05 (right
    now 0.018)
  • Modulates the effects of precession of the
    equinox -- greater effects with very elliptic
    orbit when perihelion is during NH winter
  • Much cooler in NH summer -- support Glaciation
    because winter snows wont melt

109
Obliquity
  • Axis tilt now is about 23.5 degrees -- in the
    middle of the range of tilts.
  • Tilt varies with a period of 41,000 years between
    22 and 24.5 degrees
  • Smaller tilt favors glaciation -- if NH winters
    are warm
  • Note that even warm winters are cold enough for
    snow….you want warmth because that means more
    moisture is available, and because summers are
    cooler so glaciers wont melt

110
What is not natural ? (to the extent that you
consider anthropogenic changes unnatural,
although man is a part of the ecosystem!)
  • Large increase in CO2 to atmosphere due to
    burning of fossil fuels
  • Increases greenhouse effect warming
  • CO2 values now very high (not as high as when
    dinosaurs roamed)
  • Lots of particulate matter from burning fossil
    fuels
  • Increases shading of Earth cooling

111
One Aspect of more CO2
  • Increased plant growth
  • When theres more CO2 in the atmosphere, all
    plants grow more vigorously
  • Carbon dioxide water yields sugars and oxygen
    (this is how plants remove CO2 from the
    atmosphere -- they convert it to sugar).
  • Plants use carbon dioxide in different ways.
    Response to enhanced CO2 varies by species --
    some good plants grow faster, some weeds grow
    faster

112
What are some effects of warming?
  • Longer summers
  • Would the number of cold frontal passages
    decrease? That will increase the length of
    pollution events over the US
  • Longer growing season for some plants
  • Some plants require a specific amount of cool
    weather
  • Warmer oceans mean more hurricanes?
  • Reality Only the Atlantic Basin shows hurricane
    activity trending upwards in the past 23 years

113
Does Global Warming Warming everywhere on the
Globe?
  • NO!
  • Studies show strongest warming at Poles
  • Relatively less warming at Equator
  • Local effects (shut down of Thermohaline
    circulation, for example) could cause dramatic
    cooling in one location even though the Globe as
    a whole warms

114
Warming Flooding
  • Glacier meltwater increases ocean levels
  • 6.5 m if Greenland ice cap melts
  • 8 m and 65 m if west Antarctic and east Antarctic
    ice caps melt
  • Prediction of 5 to 15-inch rise by 2100
  • 1-meter rise Half of Bangladesh is underwater
  • Thermal expansion of sea water as it warms raises
    ocean levels and warmer water cannot hold as
    much CO2 in solution
  • Stronger hurricanes over warmer waters have
    higher storm surges.

115
Glaciers are sensitive to temperature and
precipitation
  • Most Glaciers retreated in 1900s
  • 80 of the glaciers on Kilimanjaro have melted
  • Most glaciers in Glacier National Park have
    retreated
  • Also examples in the Andes and Antarctica
  • Is this from warmth or dryness? Not known for
    sure

116
Blue Retreating Glaciers Red Advancing Glaciers
Drake Peninsula, Antarctica
117
Example From Alaska
118
From The Alps
119
Glacier National Park
120
1993
Mt. Kilimanjaro
2000
121
What happens when Glaciers melt?
  • Albedo drops
  • Earth warms up
  • Glaciers melt some more
  • Sea levels rise
  • Are glaciers melting or evaporating?

122
Collapse of Larsen Ice shelf in
Antarctica, summer 2002
123
Lake Ice Seasons are shorter
  • Canada, Europe, USA, Japan Lake Ice records are
    centuries long
  • Ice appears 8.7 days later than 150 years ago
  • Ice melts 9.8 days earlier than 150 years ago

124
Some Climate Features confound the record in the
short term
125
Other Lakes
126
Other Lakes
127
Other Lakes
128
Sea Ice over Arctic Ocean
  • Decreasing, consistent with predictions
  • Each year shows more of a decrease
  • Decreases albedo, which causes further
    warming/melting
  • Open Arctic Ocean source of plenty of moisture
    to yield heavy snows and glaciation
  • Model studies stress the importance of wind in
    ice formation/melting over the Arctic, yet how
    the wind changes with warming is not well
    understood

129
Where will most change occur
  • From Computer Simulations
  • AT THE POLES
  • Snow-albedo feedbacks?

130
How is change manifest?
131
Temperature Anomalies at the Pole
132
Arctic is getting cloudier with time
133
Shorter time when roads on ice are open
134
Permafrost is warming!
135
Siberian Permafrost is warming, too again!
136
New species (in this case, birds) are colonizing
the Arctic, Moving north from warmer latitudes
137
Other species, Black Guillemots are declining
138
Problems for migratory birds
  • When birds leave might be tuned to the Sun
    (amount of daylight)
  • When prey emerges might be tuned to temperature
  • Time of departure for birds stays constant
  • Time when food is available gets earlier and
    earlier

139
Bering Sea is warming up!
140
Number of days with ice after 15 March 56-58 N/
163-165 W
141
Shrimp catch way up…cod catch way down!
142
Sea Ice in Arctic is decreasing
143
Here is 2005
144
Glaciers are in retreat
145
Glacier Volumes in NH are dropping
Eurasian Arctic
Russian Arctic
Total
N. American Arctic
146
(No Transcript)
147
For More Information
  • http//www.arctic.noaa.gov/detect

148
The big question
  • Is the increase linear, or part of an oscillation
    of unknown cause?
  • Hard to tell if youre in a linear increase or
    wave as its occurring
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