Ch. 19 Climate Disruption & Ozone Depletion. How Might the Earth’s Temperature & Climate...

Ch. 19

Climate Disruption & Ozone Depletion

How Might the Earth’s Temperature & Climate Change in

the Future? * Considerable scientific evidence indicates that the earth’s atmosphere is warming, because of a combination of natural effects and human activities, and that this warming is likely to lead to significant climate disruption during this century.

Weather & Climate Are Not The Same

Weather• Short-term changes

in atmospheric variables in given area over a period of hours/days

• Temperature• Precipitation• Wind• Barometric

Pressure

Climate• Average weather

conditions of a particular area over long period of time (decades, centuries, thousands of years)

• Temperature• Precipitation

Minimum Period = 3 decades

Climate Change is NOT New

Over the past 4.7 billion years the climate has been altered by– Volcanic emissions

Climate Change is NOT New

Over the past 4.7 billion years the climate has been altered by– Changes in solar input

Climate Change is NOT New

Over the past 4.7 billion years the climate has been altered by–Movement of the continents

Climate Change is NOT New

Over the past 4.7 billion years the climate has been altered by– Impacts by meteors

Climate Change is NOT New

Over the past 4.7 billion years the climate has been altered by– Changing global air and ocean

circulation

Climate Change is NOT New

Over the past 900,000 years– Glacial and interglacial periods

Climate Change is NOT New

• Over the past 10,000 years– Interglacial period

• Over the past 1,000 years– Temperature stable

• Over the past 100 years– Temperature changes; methods of

determination

Estimated Changes in the Average Global Temperature of

the Atmosphere

Fig. 19-2, p. 494

Fig. 19-2a, p. 494

17

Aver

age

surf

ace

tem

pera

ture

(°C)

800 700 600 500 400 300 200 100

Thousands of years ago

16

14

910

11

12

13

15

900 Present

Fig. 19-2b, p. 494

15.0

Aver

age

surf

ace

tem

pera

ture

(°C)

1880 1900 1920 1940 1960 1980 2000 2020

Year

14.8

14.6

14.4

14.2

14.0

13.8

13.6

*

Fig. 19-2c, p. 494

TEMPERATURE CHANGE (over past 22,000 years)

2

1Agriculture established

End of last ice age-2

Average temperature over past 10,000 years = 15°C (59°F)

-4Tem

pera

ture

cha

nge

(°C)

20,000 2,000 200 100 Now

Years ago

0

-1

-3

-5

10,000 1,000

Fig. 19-2d, p. 494

0.5

0.0

-0.5

Tem

pera

ture

cha

nge

(°C)

-1.0

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100Year

How do we know past changes in temperature?

• Radioisotopes in rocks & fossils• Plankton & radioisotopes in ocean

sediments• Pollen from lake bottoms• Ice cores from ancient glaciers• Tree rings• Radioisotopes in corals• Historic record – since 1861• Temperature measurements

Ice Cores Are Extracted by Drilling Deep Holes in Ancient Glaciers*

Fig. 19-3, p. 495

The Natural Greenhouse Effect(tropospheric heating effect)*

Greenhouse Gases (1% of earth’s lower atmosphere)

• Water Vapor (H2O)

• Carbon Dioxide (CO2)

• Methane (CH4)

• Nitrous Oxide (N2O)

How does the greenhouse effect work?

1. Heat radiates into atm. from earth2. Causes molecules of gases to

vibrate3. Molecules release infrared

radiation (even longer wavelength)4. Radiation interacts w/ molecules 5. kinetic energy - warms lower atm.

& earth’s surface6. Overtime affects earth’s climate.

Without the greenhouse effect, earth would be frigid and uninhabitable

So, what’s the

problem? *

Global Climate Change

• AKA Global Warming • Caused by ENHANCED

Greenhouse Effect

CO2, NOX, CFCs, CH4

These gases absorb infrared (IR) radiation in upper atmosphere (stratosphere) and trap heat in lower atmosphere (troposophere) ABOVE “normal” levels, increasing greenhouse effect hence the name Greenhouse Gases

Global Climate Change Caused by

CO2 Concentration in atmosphere from: – Burning fossil fuels– Land conversion (loss of plant

material that absorb CO2)

• 2010: 389 ppm• 2050: 560 ppm• 2100: 1,390 ppm• 450 ppm as tipping point

other gases in atmosphere such as: –NOx, CFCs, CH4

Global Climate Change Caused by

Human Activities Emit Large Quantities of Greenhouse

Gases• Since Industrial Revolution – CO2, CH4, and N2O emissions higher

–Main sources: agriculture, deforestation, and burning of fossil fuels

• Correlation of rising CO2 and CH4 with rising global temperatures

Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels

Fig. 19-4, p. 496

Correlation of CO2 and Temperature

Fig. 19-5, p. 497

Greenhouse Gases from Human Activities

Greenhouse Gas

Average Time in the Troposphere

Relative Warming Potential (CO2)

Carbon Dioxide 50-120 years 1

Methane 12-18 years 23

Nitrous Oxide 114-120 years 296

Chloroflorocarbons

11-20 years 900-8,300

Hydrochloro-flurocarbons

9-390 years 470-2,000

Hydroflurocarbons

15-390 years 130-12,700

Halons 65 years 5,500

Carbon Tetrachloride

42 years 1,400

Intergovernmental Panel on Climate Change (IPCC)

• Established 1988• Document past and project

future climate changes• Includes more than 2,500

scientists from more than 130 countries

IPCC Major Findingssee page 497

– 90–99% likely that lower atmosphere is warming• Especially since 1960• Mostly from human-caused increases in

greenhouse gases• Earth’s climate is now changing from

increased greenhouse gases

– Increased greenhouse gas concentrations will likely trigger significant climate disruption this century

– Ecological, economic, and social disruptions

Climate Change & Human Activities

• Increased Use of Fossil Fuels (CO2, CH4)

• Deforestation (CO2, N2O)

• Cultivation of Rice Patties (N2)

Global Warming = ENHANCED Greenhouse Effect–Melting icecaps & glaciers– Coral reef bleaching –Other

Global Warming Effects *

1. Melting ice caps & glaciers a. Evidence = retreating glaciers,

shrinking ice sheets

Global Warming Effects

2. Sea Level Rise a. FROM added

volumes of freshwater BUT also from thermal expansions

b. Coastline threats

(resulting in pop. displacement – LA, NYC, Miami)

Areas of Florida to Flood If Average Sea Level Rises by One

Meter

Fig. 19-11, p. 507

Global Warming Effects

3. Permafrost Decline in tundra regions (microclimate changes)

Global Warming Effects

3. Permafrost Decline in tundra regions (microclimate changes) –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

Global Warming Effects4. In precipitation patterns

a. Frequent drought, rain, snow, flooding

b. Increased frequency and intensity of storms over warmed surfaces (Sandy/Katrina)

Global Warming Effects5. In biology

a. Migration patterns disruptedb. Food web disturbancesc. Habitat fragmentation (reduced

realized niche)

Global Warming Effects

6. Human Healtha. Health related

illnessesb. Disease spread by

organisms now with extended ranges (mosquitos & malaria)

Global Warming Effects

7. Agriculture a. Sea level rise will

impact farmland by flooding coastal regions

b. Severe Droughtc. Shift in farming

regions

Factors Contributing to Global Warming

Biggest Factor = CO2 Emissions

World’s Larges Emitters of CO2

Largest emitters, 20091. China2. United States3. European Union (27 countries)4. Indonesia5. Russia6. Japan7. India

World’s Larges Emitters of CO2

Factors Contributing to Global Warming

Waste Heat– Second Law of Thermodynamics!!– Burning Fossil Fuels = CO2 emissions + Waste

Heat

Factors Contributing to Global Warming

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