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Global Effects

Lecture #21HNRT 228 Spring 2015Energy and the EnvironmentAdapted from GMU, UNM and USGS

First: Latest About Pollution

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Second: Latest About CO2

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Chapter Material Overview

• Earth as a planet• The polar regions and sea ice effects• The stratospheric ozone situation• Another look at greenhouse gasses• Climate change• Global warming

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iClicker Question

Which of the following layers of the atmosphere is highest above the surface of the Earth?

A TroposphereB StratosphereC ThermosphereD MesosphereE Ozone Layer

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iClicker Question

What is the primary ingredient of the Earth's atmosphere?

A NitrogenB OxygenC Nitrogen and oxygen in equal partsD HydrogenE Carbon dioxide

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iClicker Question

In what part of the atmosphere does weather occur?

A HydrosphereB StratosphereC IonosphereD TroposphereE All of the above

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iClicker Question

How rapidly a planet loses its atmosphere depends on the planet's

• I. mass• II. atmospheric composition• III. temperature• IV. rotation period

A I & IIB III & IVC I, II, & IIID II, III, & IVE I, II, III, & IV

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iClicker Question

The presence of Earth’s magnetic field is a good indication that

A there is a large amount of magnetic material buried near the North Pole.

B there is a quantity of liquid metal swirling around in the Earth's core.

C the Earth is composed largely of iron.D the Earth is completely solid.E there are condensed gasses in the core of

the Earth.

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The Earth

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General Features

Mass: MEarth = 6 x 1027 g

Radius: REarth = 6378 km

Density: = 5.5 g/cm3

Age: 4.6 billion years

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Earth's Internal Structure

Crust: thin. Much Si and Al(lots of granite). Two-thirds covered by oceans.

How do we know? Earthquakes. See later

Mantle is mostly solid, mostly basalt (Fe, Mg, Si). Cracks in mantle allow molten material to rise => volcanoes.Core temperature is ~6000 K. Metallic - mostly nickel and iron. Outer core molten, innercore solid.

Atmosphere very thin

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Earth's Atmosphere78% Nitrogen21% Oxygen

gas is ionized by solar radiation

ozone is O3 , which absorbs solar UV efficiently, thusheating stratosphere

commercial jet altitudes

room temperature

Original atmosphere changed over time. Atmosphere today is largely due to volcanoes and life (especially plant).

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Ionosphere

Particles in the upper reaches of the atmosphere are ionized by the sun.

Radio signals below ~20 MHz can “bounce” off the ionosphere allowing communication “over the horizon”

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Convection

Earth's surface heated by Sun. What would happen if it couldn't get rid of the energy as fast as it gets in?

Convection causes both small-scale turbulence and large scale circulation patterns. It also occurs within Earth, on other planets, and in stars.

Convection also occurs when you boil water, or soup. Think of Earth's surface as a boiling pot!

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The Greenhouse Effect

Main greenhouse gases are H2O and CO2 .

If no greenhouse effect, surface would be 40 oC cooler!

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iClicker Question:

The dinosaurs were most likely wiped out by:A: disease

B: hunting to extinction by cavemen

C: a giant meteor impact

D: the close passage of another star

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iClicker Question:

A leading cause of Global Warming is:A: Increased soot (smog) in the atmosphere.

B: Increased carbon dioxide in the atmosphere.

C: The Earth is getting closer to the sun.

D: The luminosity of the sun is steadily increasing.

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iClicker Question:

The Greenhouse effect would not occur if:A: The Earth had no atmosphere.

B: The amount of carbon dioxide doubled.

C: We got rid of all the forests.

D: The Earth didn’t have an ocean.

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Burning carbon-containing fossil fuels produces carbon dioxide.

(Combustion)

C + O2 CO2

PollutionPollution

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CO2: Most Significant Greenhouse GasCO2: Most Significant Greenhouse Gas

Source: ACIA 2004

Jennifer Allen graphic

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CO2

CH4

Humans have increased carbon dioxide (CO2) in the atmosphere by

more than 35% since the Industrial Revolution. (National Oceanic and Atmospheric Administration 2006)

The most carbon dioxide in 650,000 years. (IPCC 2007)

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Temperature Measurements“Warming of the climate system is UNEQUIVOCAL” (IPCC 2007)

Top 11 warmest years on record have all occurred in the last 12 years.(IPCC 2007)

2006 warmest year on record in continental US. (NOAA 1/07)

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Alaska as Ground Zero for WarmingAlaska as Ground Zero for Warming

In past 50 years,

Alaska: Temperatures haveincreased

•4oF overall(National Assessment Synthesis Team)

Worldwide:Temperatures haveincreased

•Slightly more than 1oF

(IPCC 2007)

Surface Air Temperature Trends 1942-2003

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Chapman and Walsh, 2004

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Snow and sea ice reflect 85-90% of sun’s energy.

Ocean surface and dark soil reflect only

10-20%.

The Albedo Effect

“White shirt versus Black shirt”

Why has Alaska warmed the most?Why has Alaska warmed the most?

Increased melting of

snowand sea ice

Increased melting of

snowand sea ice

More of sun’s heat energy is absorbed

More of sun’s heat energy is absorbed

More dark earthand ocean surface

is exposed

More dark earthand ocean surface

is exposedLand or water warms faster

Land or water warms faster

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(ACIA 2004)

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Source ACIA, 2004Jennifer Allen Animation

An area twice the size of Texas has melted away since 1979 (over 20%

decrease). (National Snow and Ice Data Center 2005)

Ice 40% thinner. (Rothrock,D.A, et al. 1999)

Ice only 6 – 9 feet thick at North Pole (NOAA FAQ 2007).

Northwest passage opened Aug 21, 2007

Impacts in Alaska1. Melting

Melting Sea IceMelting Sea Ice

1978 1983 1988 1993 1998 2003

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Source: NSIDC, 2005

ARCTIC SEA ICE AREA1979-2005

2005

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Impacts in Alaska1. Melting

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Melting Sea IceMelting Sea Ice

Arctic Ocean could be ice free in summer by 2040

(U.S National Center for Atmospheric Research 2006).

“Our research indicates that society can still minimize the impacts on Arctic ice.” Dr. Marika Holland, National Center for Atmospheric Research

2000 2040

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Impact World-wide1. Melting

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Impact on Ski IndustryImpact on Ski Industry

• In the US skiing is a $5B industry• 2006 saw a 78% decline in skiers visiting the pacific northwest US• Ski Seasons have shortened by 1 day/year for the last 20 years• Many European ski resorts below 1800 m (6000 ft) will close • 50 to 90% of Alpine glaciers will be gone by 2100• Some resort to snowmaking

• Expensive• Requires lots of water• Requires lots of energy

• In New Mexico, many ski areas can’t open until after Xmas

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Impacts in Alaska1. Melting

The rapid retreat of Alaska’s glaciers represents about 50% of the estimated mass loss by glaciers through 2004 worldwide. (ACIA 2004)

Loss of over 588 billion cubic yards between ’61 and ’98. (Climate Change 11/05)

Alaska’s glaciers are responsible for at least 9% of the global sea level rise in the past century. (ACIA 2004)

19411941

20042004

Glacier Bay (Riggs Glacier)

USGS photo

Bruce Molnia photo

Glacial RetreatGlacial Retreat

20032003

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McCall Glacier

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Melting of the Greenland Ice Sheet

• According to NASA scientists, the Greenland ice sheet is melting faster than it is being replaced, contributing to sea level rise

• The loss of ice from Greenland doubled between 1996 and 2005

• From 1996 to 2000, the largest acceleration and mass loss came from southeast Greenland

• From 2000 to 2005, the trend extended to include central east and west Greenland

• It is estimated that 69 per cent of the ice-mass loss in recent years came from eastern Greenland

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Greenland ice is declining faster than expected

• Between 2003 and 2005 the low coastal areas of Greenland lost 155 gigatons of ice per year due to excess melting while the high elevation interior gained 54 gigatons annually from excess snowfall

• Between 2004 and 2006, the rate of melting accelerated, with the massive ice sheet melting two and one-half times faster than the previous two-year period

• Greenland lost roughly 164 cubic miles of ice from April 2004 to April 2006—more than the volume of the North American Great Lake Erie

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Greenland Ice Sheet

Dramatic ice mass losses concentrated in the low-elevation coastal regions, with nearly half of the loss coming from southeast Greenland

NASA Earth Observatory

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Greenland Ice Sheet

Greenland is now losing 20 percent more mass than it receives from new snowfall each year.

NASA Earth Observatory

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Greenland Ice Sheet

University of Colorado, CIRES

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Melting of ice in Greenland

2001-2003:

A significant increase in the melting area has been observed along the edge of the ice cap in Greenland.

NASA Earth Observatory

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Retreat of Ice and Snow in Greenland

NASA Earth Observatory

Ice loses in Greenland range from 5 to 25 centimeters of water equivalent per year

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This May 2005 picture of Helheim Glacier, demonstrates high calving activity associated with faster glacial flow

Helheim glacier, located in southeast Greenland, is now one of the fastest moving glaciers in the world1986-2006: These images show the retreat of Helheim glacier’s calving front

Calving of Helheim Glacier, Greenland

The glacier’s peak rate of flow has increased from 8 km/yr in 2000 to 11 km/yr in 2005

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Dramatic changes in Arctic Sea Ice

Imagine an ice-free Arctic

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Evidence of extensive snowmelts in West Antarctica

• January 2005: Areas of extensive snowmelt (shown in yellow and red) have been discovered by a team of NASA and university scientists in response to warmer temperatures in west Antarctica .

• The combined area affected is as big as California.

NASA Jet Propulsion Laboratory

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Breakup of Larsen ice shelf (Antarctic Peninsula)

220 metres thick Larsen B shelf existed for at least 400 years prior to breakup

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Disintegration of the Larsen B Ice Shelf, Antarctic Peninsula

The ice shelf disintegrated suddenly in March 2002 due to warm summer temperatures

NASA Earth Observatory

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Breakup of Antarctica’s Ross Ice Shelf

• An iceberg (B-15J) of size of a small United States state cracked off the Antarctica’s Ross Ice Shelf in March 2000

• On February 1, 2007, three new icebergs were formed due to the break up of the original iceberg

NASA Earth Observatory

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Breaking Off Filchner Ice Shelf Antarctica

Filchner Ice Shelf is the largest ice shelf on the planetIn 1986 the front edge of Ice Shelf broke off into three enormous icebergs

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Calving of Ninnis Glacier Antarctica

22 January 2000: The Ninnis Glacier Tongue soon after the initial calving5 February 2002: Iceberg split into two sections and started moving away from Ninnis Glacier

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Cracks on Drygalski Ice Tongue Antarctica

The ice tongue was discovered in 190221 February 2005: Drygalski calved an iceberg Image shows cracks formed by time and ocean currents

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Shrinking Lake Chad shared by Nigeria, Niger, Chad and Cameroon

Persistent drought has shrunk the lake to about a tenth of its former size

• 1972: Larger lake surface area is visible in this image• 2001: Due to regionally drying climate and human demand for fresh water, Lake Chad is fraction of what is once was• 2004: In many places, the green of wetlands is being replaced by drifting sand dunes (tan ripples mixed with green)

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Shrinking Breidamerkurjökull Glacier Iceland

• 1973-2000: Images show glacier has receded and the glacial lake at its tip has enlarged

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• 1986: Images show Degradation of forest area

• 2001: Between 1984 and 1999, 38 per cent of forests were degraded

Ayles Ice Shelf, Ellesmere Island, Canada

Ayles Ice Shelf on Ellesmere Island, broke free on August 13, 2005 and drifted out to the sea

NASA Earth Observatory

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Disappearing Icecap of Mt. Kilimanjaro, Tanzania

Africa’s highest mountain with a forest belt having rich diversity of ecosystems

• 1976: Glaciers covered most of the summit

• 2000: The glaciers had receded alarmingly

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Retreat of Gangotri Glacier, India

NASA Earth Observatory

• Gangotri glacier has retreated more than 850 meters, in the last 25 years

• It has retreated more than 76 meters from 1996 to 1999

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Glacial Lakes and Glacial Lake Outburst Floods

Jeffrey Kargel, USGS/NASA JPL/AGU

• Glacial lakes are formed due to the melting of ice and snow from glaciers

• Due to the faster rate of melting from the glaciers, possibly due to global warming, water is accumulating at an increasing rate in these lakes

• Sudden outburst results in Glacial Lake Outburst Flood (GLOF) downstream causing destruction of life and property

Glacial Lakes in the Bhutan-Himalaya Region

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Retreat of Upsala Glacier, Argentina

NASA Earth Observatory

The Upsala glacier has retreated more than 4 kilometers since late 1960’s to mid 1990’s and continues to retreat

January 2004 position

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Retreat of San Quintin Glacier, Chile

NASA Earth Observatory

The San Quintin Glacier appears to be losing mass and retreating

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Impacts in Alaska3. Animals

Animals at RiskAnimals at Risk

Rising temperatures Shrinking habitat Food harder to get Expanding diseases Competition

Polar bearsWalrusesIce seals

Caribou

Black guillemotsKittiwakesSalmon

Arctic grayling

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Inundation

Sea level has increased 3.1 mm/year between 1993 and 2003 (IPCC 2007).

This is 10-20 times faster than during the last 3,000 years (ACIA 2004).

0.4-0.6 meters of sea level rise by 2100 if 3 times pre-industrial CO2 or 1% increase/year (Overpeck et al. 2006).

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Inundation InundationInundation from Four Meter Sea Level Rise (or, 1m rise + 3m storm surge)

Weiss and Overpeck, 2006

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What We Can DoWhat We Can Do

1. Is it Achievable?

2. Action Is Possible at Every Level

• Individual• Corporate• Local• State• Federal• International

3. Some Steps

R E D U C E C O 2

E M I S S I O N S

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What We Can Do

Wind PowerWind Power

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Measuring Your Carbon Footprint

Major Carbon Contributors:

Electric Consumption Gas/Heating Oil

Consumption Car and Miles Driven Miles Flown Recreational Vehicle Use

Average Footprint is 30,000 pounds

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Conservation: Three Examples

Unplug Appliances Vampires! 43 billion kWH lost/year in

US Est: 1,000 lbs/year/person

Pump Up Tires 4 million gallon of gas

wasted daily in US Extends life of tires by 25% Est: 1,000 lbs/year/person

Lower Thermostat 2 degrees Est: 2000 lbs/year/person

What We Can Do

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Energy Efficiency: Two Examples

Compact Fluorescents

Four to six times more efficient

Est: for each bulb converted, save about 100 lbs/year

Bus/Walk/Bike Save money on fuel

and maintenance Est: 5,000 lbs/year

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EarthquakesThey are vibrations in the solid Earth, or seismic waves.

Two kinds go through Earth, P-waves ("primary") and S-waves ("secondary"):

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How do they measure where Earthquakes are centered?

* *

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seismic stations

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Like all waves, seismic waves bend when they encounter changes in density. If density change is gradual, wave path is curved.S-waves are unable to travel in liquid.Thus, measurement of seismic wave gives info on density of Earth's interior and which layers are solid/molten.

But faint P wavesseen in shadow zone,refracting off denseinner core

Curved paths ofP and S waves:density must slowlyincrease with depth

Zone with no S waves:must be a liquid corethat stops them

No P waves too:they must bend sharplyat core boundary

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Earth's Interior Structure

Average density

CrustMantleCore

5.5 g/cm3

3 g/cm3

5 g/cm3

11 g/cm3

Density increases with depth => "differentiation"

Earth must have been molten once, allowing denser material to sink, as it started to cool and solidify.

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Earthquakes and volcanoes are related, and also don't occur at random places. They outline plates.

Plates moving at a few cm/year. "Continental drift" or "plate tectonics"

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When plates meet...

1) Head-on collision (Himalayas)

2) "Subduction zone" (one slides under the other) (Andes)

3) "Rift zone" (two plates moving apart) (Mid-Atlantic Ridge, Rio Grande)

4) They may just slide past each other (San Andreas Fault)

side view

top view

=> mountain ranges, trenches, earthquakes, volcanoes

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iClicker Question:

Sunlight absorbed by the Earth’s surface is reemitted in the form of?A: radio waves

B: infrared radiation

C: visible radiation

D: ultraviolet radiation

E: X-ray radiation

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iClicker Question:

What steps are you willing to take to reduce your carbon dioxide footprint?A: Walk/bike/bus to work

B: Unplug appliances when not in use

C: Replace light bulbs with compact fluorescents

D: Wash clothes in cold or warm water

E: Buy a Prius

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The Mid-Atlantic Ridge is a rift zone.

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What causes the drift?

Convection! Mantle slightly fluid and can support convection. Plates ride on top of convective cells. Lava flows through cell boundaries. Earth loses internal heat this way.

Cycles take ~108 years.

Plates form lithosphere (crust and solid upper mantle).Partially melted, circulating part of mantle is asthenosphere.

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Pangaea: 200 million years ago, all the continents were close together.