Human Activities and the Earth’s Valuable Water and Air Resources

Ozone Depletion Global Warming and Global Climate Change Acid Rain Biological Magnification Human Impacts on Water, Air, Fisheries What we can do Objectives:

Ozone layer (20-50km up) protects the Earth from UV radiation Gases (CFCs) used in aerosols break down ozone causing the “holes” over the Arctic and Antarctica Montreal Protocol stopped production of CFC’s on January 1, 1996 Holes are not growing but will not recover until ! Ozone Depletion

Excess UV radiation: Skin cancer Cataracts Immune System Problems Other unknown effects on plant/animal life

Caused by gases (mostly CO 2 ) that trap heat Burning of fossil fuels, cutting/burning of forests releases CO 2 faster than Carbon cycle can remove it Temperatures have risen 0.6 o C. since industrial age Since 1980, average temp risen 0.3 O C. Global Warming

Global Climate Change  Melting of permafrost, increasing release of greenhouse gases  Melting of poles  Rising sea level  Flooding, Drought  Loss of habitat, species extinction  Loss of coral reef ecosystems (fisheries, tourist revenue, natural storm barriers)  All the above have economic impacts

Acid Rain  Burning of fossil fuels release nitrogen and sulfur gases  Combined with H2O vapor = nitric and sulfuric acids  Fall as acid rain  Plants damaged  Soil chemistry altered, potentially hazardous compounds released and flow into water system (mercury) BIOMAGNIFICATION

Eastern U.S: average pH of 3.6, with some values as low as pH 2.6 Los Angeles: pH of fog has been measured at 2.0

Biomagnification Pesticides and heavy metals work their way into rivers or lakes and move up the food chain becoming more concentrated at each level “Silent Spring” by Rachel Carson

FOR EXAMPLE: If in one day a small fish eats 1,000 plankton and a larger fish eats 1,000 small fish, the human who catches the larger fish is ingesting all the toxins that were in a 1,000,000 plankton! (1,000 x 1,000 = 1,000,000) Add that up over a lifetime and you’re in trouble!

Clean Water Renewable but not unlimited!  same water is recycled (the water cycle!)  BUT if contaminated during that cycle, may not be reusable Two issues: Pollution and loss of water filtration!

Some water pollutant sources:  Sewage  Runoff: agricultural fertilizers, factory farms  Factory outfall

Contaminated drinking water Contaminated food animals (biological magnification of toxins from the environment over their life spans) Unbalanced river and lake ecosystems that can no longer support full biological diversity Deforestation from acid rain Loss of natural beauty Some Effects of Water Pollution

For water use to be sustainable we need to protect the natural systems of the water cycle.  Preserve wetland areas = water filtration  Think before you pave it = less filtration  Think before you cut it = less transpiration llllllllllllll

Fisheries Overfishing - harvesting fish faster than they reproduce An example of “tragedy of the commons” Everyone uses the resource but no one maintains it If properly managed, can be a renewable resource

Air Air Quality Issues (caused by burning of fossil fuels): Smog Particulates - microscopic particles of ash and dust Acid Rain Their Effects: Human health Deforestation

Don’t litter Turn off lights, all electronic equipment Recycle - don’t fill up our landfills Conservative or little use of fertilizers Walk or bike when possible Drive more fuel efficient vehicles Support wetlands preservation Develop sustainable energy sources: Wind, solar, fuel cells Think before you pave it Use sustainable building practices - green space and gravel, porous paving Design pedestrian friendly cities Things we can do