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New Core Curriculum

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New Core Curriculum Foundations of Scientific Process Factors that govern Global & Local Climate – PowerPoint PPT presentation

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Title: New Core Curriculum


1
New Core Curriculum
Foundations of Scientific Process
Factors that govern Global Local Climate
2
Life Atmospheric Conditions Climate
Proxies- needed to infer
past climate-related changes
3
Development of the Habitable Conditions on Earth
4
The History of Life on Earth
5
Elements of Habitability
  • Stability
  • Chemical Composition
  • Temperature

6
Elements of Habitability
  • Stability
  • Chemical Composition
  • Temperature
  • Temperature of a planet is determined from an
    energy balance
  • Energy IN
    Energy OUT
  • Planets atmosphere
  • Water vapor
  • Carbon dioxide
  • Methane
  • Nitrous oxides
  • Sulfur dioxide
  • Aerosols
  • Stars Luminosity
  • Distance planet-star
  • Tilt of planets axis, eccentricity of planet's
    orbit
  • Reflectivity of planet, Albedo (cloud cover,
    surface ice, vegetation, aerosols)

7
Energy input Earth output
1) Ein (from the Sun)
Eout 2) Reflectivity (Albedo) 3) Greenhouse
Concentration
8
How do we determine the energy into the climate
system?
B L/4pd2
Distance from Sun
9
  • Sunspots!
  • More sunspots brighter sun
  • Small effect 1-2 W/m2 of 1360 W/m2
  • Sunspot cycles occur over decades to hundreds of
    years

10
1 - 2 W/m2
Year
significant climate responses to sun spots
11
Milankovitch cycles
100,000
41,000
23,000
years
years
years
Precession is the change in the direction of the
Earth's axis of rotation relative to the fixed
star.
The angle of the Earth's axial tilt varies with
respect to the plane of the Earth's orbit.
The eccentricity is a measure of the departure of
this ellipse from circularity.
12
Green house gases
How do we determine the energy out of the climate
system?
Albedo
Clouds, ice, white aerosols reflect about 30 of
incoming sunlight back to space
13
Albedo Reflectivity fraction of incoming
radiation that is not absorbed, yet just bounces
back in space
Sample albedos Sample albedos
Surface Albedo
Fresh asphalt 0.041
Conifer forest (Summer) 0.082
Worn asphalt 0.121
Bare soil 0.173
Green grass 0.253
Desert sand 0.404
New concrete 0.553
Fresh snow 0.800.903
Venus 0.65 Mars 0.15 Earth 0.3 Moon
0.12 Jupiter 0.52 Europa 0.67
14
Volcanoes cool climate, briefly
Mt. Pinatubo - 1994
Natural effects that Increases Earths Albedo
Big eruptions inject aerosols into the upper
atmosphere. Earth becomes more reflective for 2-3
years
15
Greenhouse Effect gases (H2O, CO2,..) trap heat
in the atmosphere
H2O vapor constitutes the largest of the
greenhouse effect (absorbs terrestrial radiation)
Greenhouse gases are highly influential
16
How do we determine the energy out of the climate
system?
17
Heat Temperature
  • Heat energy of atomic and molecular motion
  • Temperature measure of average kinetic energy of
    moving atoms and molecules
  • Ex Room temperature
  • T 293 K
  • Air particles as N2
  • (m 2 x 14 g/mol)
  • vavg 450 m/s
  • T (in Kelvin)
  • m (atomic mass unit,
    protons neutrons)

18
Complicated Feedback Loops in-play
  • Climate
  • average weather (average temperature) for the
    whole planet that prevails over certain
    time-span
  • it is variable with time
  • it is a sensitive system

3 factors determining the global climate
  1. Ein (from the Sun)
  2. Reflectivity (Albedo)
  3. Greenhouse Concentration

19
What controls local climate? differential heating
What causes Seasons?
20
Elements of Habitability
  • Stability
  • Chemical Composition
  • Temperature
  • Temperature of a planet is determined from an
    energy balance
  • Energy IN
    Energy OUT
  • Planets atmosphere
  • Water vapor
  • Carbon dioxide
  • Methane
  • Nitrous oxides
  • Sulfur dioxide
  • Aerosols
  • Stars Luminosity
  • Distance planet-star
  • Tilt of planets axis, eccentricity of planet's
    orbit
  • Reflectivity of planet Albedo (cloud cover,
    surface ice, vegetation, aerosols)

21
Global Trends
Climate Change (global worming, sea-level rise,
coastal flooding, extreme weather) HOW DO WE
KNOW?
22
The Earths Past (evidence from the geologic
record)
Proxies- needed to infer
past climate-related changes
23
Natural Recorders of Temperature
Paleo-climate Proxies
Tree Rings
Ice Core
Sedimentary Layers
Glacial features
Fossils
24
Retreating glaciers Proxy for past climatic
conditions
Retreating glacier in Greenland
TODAY
  • Glaciers clean rock surface
  • Leave hills or mounds of sediments (moraines) and
    discoloration

Full extent was in 1850 AD
But this is with reference to Greenland.
Is it applicable on the
global scale?
25
Retreating glaciers in the Southern hemisphere
  • Examine retreat of glaciers elsewhere on Earth
  • Franz Josef Glacier in New Zealand
  • Compare size in 1880 AD and now
  • Retreat of glacier ?
    Climate much colder in the past

26
Retreating glaciers worldwide
Ref IPCC Report 2001
Historical records of past conditions
27
Glaciers as Proxies
Glacial grooves and striations at the base of
the Matterhorn
Like in our backyard of Central Park! Evidence
that glaciers extended here in the past over
20,000 years ago
28
Ice Core Archives
http//www.pbs.org/saf/1505/video/watchonline.htm
movie of ocean sample
29
How glaciers trap bubbles ? samples of atmosphere
  • Snow falls
  • Ice becomes closer packed
  • Eventually pores are isolated and gas is trapped
  • Gas is record of the atmosphere in the past and
    the content of various gases CO2, CH4 etc. in
    it

2-5 km length
30
Earths paleoclimate
Data CO2 content of air trapped in
ice core
31
How was an estimate of CO2 obtained?
Air bubbles trapped in the ice core

How was an estimate of temperature obtained?
Ratio of Oxygen isotopes (atoms with different
number of neutrons)
32
Calibration Curve
33
Homo Sapiens about 200 thousand years ago
34
600

500
400
Mauna Loa
300
35
(No Transcript)
36
600

500
IPCC A1B
400
Mauna Loa
300
37
Global Warming of Climate Who is responsible
for the change?
Factors responsible for Climate Variation
A) Natural Causes
B) Anthropogenic Causes
38
Natural Causes
Anthropogenic Causes
  • variations in Earths orbit
  • eccentricity, obliquity, precession
  • movement of landmasses
  • volcanic activity
  • addition of CO2
  • burn burning of coal/fossil fuels
  • deforestation (vegetation decay)
  • generation of Aerosols

39
So global climate is warming. How can we
distinguish between variations due to natural
causes and those that are induced by human
activity?
Natural Causes
Anthropogenic Causes
Climate Models as Evidence used to determine the
amount of change anticipated by accounting for
certain factors
Modern Climate Changes dominated by Human
Influence
40
Testing models against past climate The last
100 years
Climate Models as Evidence
Human Influences
Natural Influences
Modern Climate Changes dominated by
Human Influence
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