FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Chapter 6 Humans in the Biosphere Section 6-4 Charting a Course for the Future for the Future

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Charting A Course Key Concept: As We Enter The 21 st Century, Many Biologists Are Concerned About The Biological Effects Of Two Types Of Global Change: 1.The thinning, or depletion, of the ozone layer 2.Global Warming

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Oxygen Gas

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Molecule

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Depletion Ozone layerOzone layer –20/50 km above earth (12 – 31 miles) –Oxygen = O 2 –Ozone = O 3 Ozone at ground level is a pollutantOzone at ground level is a pollutant In the upper atmosphere it is VERY importantIn the upper atmosphere it is VERY important

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Layer Absorbs Ultraviolet Radiation (UV)Absorbs Ultraviolet Radiation (UV) UV Radiation Can Cause:UV Radiation Can Cause: – Sunburn –Cancer –Eye Damage –Cataracts –Decreased Resistance To Disease –Destruction of Plants & phytoplankton

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone The Universal Sunscreen

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Hole - South Pole

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Depletion Discovered in 1970’s over AntarcticaDiscovered in 1970’s over Antarctica Hole is growing largerHole is growing larger Now occurring over the ArcticNow occurring over the Arctic –grew large enough to expose U.S.

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ozone Hole Caused By CFC’sChlorofluorocarbons CFC’s act as a catalyst CFC’s have a long half-life 2O 3 + CFC’s 3O 2

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Where Do CFC’s Originate? CFC’s found inCFC’s found in –aerosol cans –coolants used in refrigeratorsrefrigerators freezersfreezers automobile air conditioningautomobile air conditioning

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Montreal Protocol Nations Agreed to end use of CFC’s by 2000

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Change In Atmospheric Chlorine

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Global Warming

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Global Warming

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Global Warming

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Climate Change Any Climate Change will have profound effects on the Biosphere.Any Climate Change will have profound effects on the Biosphere. Over past 120 years average global temperature has increased 0.5 degrees Celsius (0.9 degrees F)Over past 120 years average global temperature has increased 0.5 degrees Celsius (0.9 degrees F) Rise between fastest in over 100 years.Rise between fastest in over 100 years.

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Climate Change Ice caps are meltingIce caps are melting Artic Sea Ice may be gone in 50 yearsArtic Sea Ice may be gone in 50 years

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT CO2 Methane (Greenhouse Gases) CO2 Methane (Greenhouse Gases) Burning Fossil Fuels, ForestsBurning Fossil Fuels, Forests Project Increase of 1 – 2 degrees Celsius by 2050Project Increase of 1 – 2 degrees Celsius by 2050 –BUT, Some scientists wonder if this is not a natural cycle. Why is it happening?

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Global Warming Effects Polar Ice MeltPolar Ice Melt Rising Sea LevelsRising Sea Levels Increase in number & severity of stormsIncrease in number & severity of storms North American droughtsNorth American droughts Shifts in plant & animal species distributionShifts in plant & animal species distribution

FOOTHILL HIGH SCHOOL SCIENCE DEPARTMENT Ways to Help the Biosphere Decrease energy consumptionDecrease energy consumption –Insulate Homes –Energy Efficient Appliances –High Mileage Cars –High Efficiency Energy Production Alternate Fuel SourcesAlternate Fuel Sources –Fuel Cells –Wind