foothill high school science department chapter 6 humans in the biosphere section 6-4 charting a...

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT

Chapter 6Humans in the Biosphere

Section 6-4 Section 6-4

Charting a CourseCharting a Course

for the Futurefor the Future


Charting A Course

Key Concept:Key Concept:As We Enter The 21As We Enter The 21stst Century, Many Century, Many

Biologists Are Concerned About Biologists Are Concerned About The Biological Effects Of Two The Biological Effects Of Two Types Of Global Change:Types Of Global Change:

1.1. The thinning, or depletion, of the The thinning, or depletion, of the ozone layerozone layer

2.2. Global WarmingGlobal Warming


Oxygen Gas


Ozone Molecule


Ozone Depletion

• Ozone layerOzone layer–20/50 km above earth 20/50 km above earth (12 – 31 miles) (12 – 31 miles)

–Oxygen = OOxygen = O22

–Ozone = OOzone = O33

• Ozone at ground level is a pollutantOzone at ground level is a pollutant• In the upper atmosphere it is In the upper atmosphere it is VERYVERY

importantimportant


Ozone Layer

• Absorbs Ultraviolet Radiation (UV)Absorbs Ultraviolet Radiation (UV)

• UV Radiation Can Cause:UV Radiation Can Cause:– SunburnSunburn– CancerCancer– Eye DamageEye Damage– CataractsCataracts– Decreased Resistance To DiseaseDecreased Resistance To Disease– Destruction of Plants & phytoplanktonDestruction of Plants & phytoplankton


Ozone

The Universal SunscreenThe Universal Sunscreen


Ozone Hole

-South Pole


Ozone Depletion

• Discovered in 1970’s over Antarctica Discovered in 1970’s over Antarctica

• Hole is growing largerHole is growing larger

• Now occurring over the ArcticNow occurring over the Arctic

• 1995 1995 – grew large enough to expose U.S.grew large enough to expose U.S.


Ozone Hole Caused By

CFC’sCFC’sChlorofluorocarbonsChlorofluorocarbons

CFC’s act as a catalystCFC’s act as a catalyst

CFC’s have a long half-lifeCFC’s have a long half-life

2O2O33 + CFC’s 3O + CFC’s 3O22


Where Do CFC’s Originate?

• CFC’s found inCFC’s found in–aerosol cansaerosol cans

–coolants used incoolants used in• refrigeratorsrefrigerators

• freezersfreezers

• automobile air conditioning automobile air conditioning


Montreal Protocol

19871987

46 Nations46 Nations

Agreed to end use of CFC’s Agreed to end use of CFC’s by 2000by 2000


Change In Atmospheric Chlorine

0

2

4

6

8

10

12

14

1950 1970 1990 2000 2010 2030 2050 2070 2090

Pa

rts

pe

r B

illi

on

Historical NoRestrictions Montreal All Nations


Global Warming


Climate Change

• Any Climate Change will have profound Any Climate Change will have profound effects on the Biosphere.effects on the Biosphere.

• Over past 120 years average global Over past 120 years average global temperature has increased 0.5 degrees temperature has increased 0.5 degrees Celsius (0.9 degrees F)Celsius (0.9 degrees F)

• Rise between 1980-2000 fastest in over Rise between 1980-2000 fastest in over 100 years.100 years.


Climate Change

• Ice caps are Ice caps are meltingmelting

• Artic Sea Ice Artic Sea Ice may be gone in may be gone in 50 years50 years


• CO2 Methane (Greenhouse Gases)CO2 Methane (Greenhouse Gases)

• Burning Fossil Fuels, ForestsBurning Fossil Fuels, Forests

• Project Increase of 1 – 2 degrees Project Increase of 1 – 2 degrees Celsius by 2050 Celsius by 2050

– BUT, Some scientists wonder if this BUT, Some scientists wonder if this is not a natural cycle.is not a natural cycle.

Why is it happening?


Global Warming Effects

• Polar Ice MeltPolar Ice Melt

• Rising Sea LevelsRising Sea Levels

• Increase in number & severity of Increase in number & severity of stormsstorms

• North American droughtsNorth American droughts

• Shifts in plant & animal species Shifts in plant & animal species distributiondistribution


Ways to Help the Biosphere

• Decrease energy consumptionDecrease energy consumption– Insulate HomesInsulate Homes– Energy Efficient AppliancesEnergy Efficient Appliances– High Mileage CarsHigh Mileage Cars– High Efficiency Energy ProductionHigh Efficiency Energy Production

• Alternate Fuel SourcesAlternate Fuel Sources– Fuel CellsFuel Cells– WindWind

foothill high school science department chapter 6 humans in the biosphere section 6-4 charting a...

Documents