New Core Curriculum Foundations of Scientific Process Factors that govern Global & Local Climate

Life – Atmospheric Conditions – Climate Proxies- needed to infer past climate-related changes Time before present (billions of years) Atmospheric CO 2 Atmospheric O 2

Development of the Habitable Conditions on Earth

The History of Life on Earth

Elements of Habitability Stability Chemical Composition Temperature

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

Energy input = Earth output 1) E in (from the Sun) E out 2) Reflectivity (Albedo) 3) Greenhouse Concentration

How do we determine the energy into the climate system? Distance from Sun B = L/4πd 2

Solar Max 2001 Solar Min 2006 Solar Max 2011 Sunspots! More sunspots = “brighter” sun Small effect: 1-2 W/m 2 of 1360 W/m 2 Sunspot cycles occur over decades to hundreds of years

significant climate responses to sun spots W/m 2 Year

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. 100,00041,00023,000 Milankovitch cycles years

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

Albedo = Reflectivity fraction of incoming radiation that is not absorbed, yet just bounces back in space Sample albedos SurfaceAlbedo Fresh asphalt0.04 [1] [1] Conifer forest (Summer) 0.08 [2] [2] Worn asphalt0.12 [1] [1] Bare soil0.17 [3] [3] Green grass0.25 [3] [3] Desert sand0.40 [4] [4] New concrete0.55 [3] [3] Fresh snow0.80–0.90 [3] [3] Venus ~ 0.65 Mars ~ 0.15 Earth ~ 0.3 Moon ~ 0.12 Jupiter ~ 0.52 Europa ~ 0.67 Venus ~ 0.65 Mars ~ 0.15 Earth ~ 0.3 Moon ~ 0.12 Jupiter ~ 0.52 Europa ~ 0.67

Volcanoes cool climate, briefly Mt. Pinatubo Big eruptions inject aerosols into the upper atmosphere. Earth becomes more reflective for 2-3 years Natural effects that Increases Earth’s Albedo

Greenhouse Effect: gases (H 2 O, CO 2,..) trap heat in the atmosphere Greenhouse gases are highly influential H 2 O vapor constitutes the largest % of the greenhouse effect (absorbs terrestrial radiation)

How do we determine the energy out of the climate system?

Heat & Temperature Heat: energy of atomic and molecular motion Temperature: measure of average kinetic energy of moving atoms and molecules  T (in Kelvin)  m (atomic mass unit, # protons + # neutrons)  T (in Kelvin)  m (atomic mass unit, # protons + # neutrons)  Ex: Room temperature  T = 293 K  Air particles as N 2 (m = 2 x 14 g/mol)  v avg ~ 450 m/s  Ex: Room temperature  T = 293 K  Air particles as N 2 (m = 2 x 14 g/mol)  v avg ~ 450 m/s

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)E in (from the Sun) 2)Reflectivity (Albedo) 3)Greenhouse Concentration Complicated Feedback Loops “in-play”

What controls local climate? differential heating What causes Seasons?

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

Global Trends Climate Change (global worming, sea-level rise, coastal flooding, extreme weather) HOW DO WE KNOW?

The Earth’s Past (evidence from the geologic record) Proxies- needed to infer past climate-related changes Time before present (billions of years) Atmospheric CO 2 Atmospheric O 2

Natural Recorders of Temperature Paleo-climate Proxies Ice Core Glacial features Tree Rings Sedimentary Layers Fossils

Retreating glaciers – Proxy for past climatic conditions TODAY Full extent was in ~1850 AD Glaciers “clean” rock surface Leave hills or mounds of sediments (moraines) and discoloration But this is with reference to Greenland. Is it applicable on the global scale? Retreating glacier in Greenland

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 Retreating glaciers in the Southern hemisphere

Historical records of past conditions Ref : IPCC Report 2001 Retreating glaciers worldwide

Glacial grooves and striations at the base of the Matterhorn Glaciers as Proxies Like in our backyard of Central Park! Evidence that glaciers extended here in the past over 20,000 years ago

Ice Core Archives movie of ocean sample

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 – CO 2, CH 4 etc. in it 2-5 km length

Data: CO 2 content of air trapped in ice core Earth’s paleoclimate

How was an estimate of temperature obtained? How was an estimate of CO 2 obtained? Air bubbles trapped in the ice core Ratio of Oxygen isotopes (atoms with different number of neutrons)

Calibration Curve

Homo Sapiens about 200 thousand years ago Nature, June ,000 YEARS AGO

Mauna Loa

Mauna Loa IPCC A1B scenario Time (years) CO2 concentrations (ppm)

IPCC A1B Mauna Loa

Factors responsible for Climate Variation: A) Natural Causes B) Anthropogenic Causes Global Warming of Climate: Who is responsible for the change? +0.6°

Natural Causes Anthropogenic Causes addition of CO 2 burn burning of coal/fossil fuels; deforestation (vegetation decay); generation of Aerosols variations in Earth’s orbit eccentricity, obliquity, precession movement of landmasses volcanic activity

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

Climate Models as Evidence: Modern Climate Changes dominated by Human Influence Testing models against past climate: The last ~ 100 years “Natural” Influences Human Influences