Mrs. Stewart Honors Biology

Human Footprint  the effects humans have on our planet

WHAT IS GLOBAL CHANGE ?  Global change includes natural and human- induced changes in the Earth's environment.  Global change can be defined as changes in the global environment (including alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems) that may alter the capacity of the Earth to sustain life.

Human dependence on the natural Environment  a resource for food supply  a major source of medicines  an energy source  a source for recreation  natural resources for industrial products

Ecological Overshoot  The WWF's (World Wildlife Fund) Living Planet Report 2004 confirms that humanity is now consuming over 20 % more natural resources than the Earth can regenerate.  We are plundering the planet at a pace that outstrips its capacity to support life.

Current Global Situation  It now takes the Earth one year and four months to regenerate what we use in a year.

Human activity = Impacts Human activity = Impacts  Human activity is a major cause of environmental change  Environment degradation has an impact not only on human beings but on all species and most natural systems

How Big is Your Footprint?  Each and every living organism consumes the Earth's resources in order to survive.  However, this consumption and subsequent waste has an impact on our ecosystems.  When these consumption and waste activities extend beyond the earth's carrying capacity, an imbalance is struck and ecological degradation ensues.

Carbon Footprint  A measure of the amount of carbon dioxide emitted through fossil fuel combustion.

Human population growth Human population growth  Our population is rapidly rising beyond the earth's ability to regenerate and sustain us.  We are exceeding the carrying capacity of our planet.

Impact of Population Growth Deforestation Over exploitation of Bioresources Pollution Rapid mining of non-biological resources

Population growth leads to  Industrialization –Burning fossil fuels –Non-renewable resources –Pollution –Increased CO 2 levels

Acid Rain  Burning of fossil fuels releases sulphates and nitrates into air  Sulphates and nitrates mix with water vapor in air and form sulphuric acid and nitric acid

Acidification of lakes  Lakes and ponds can become so acidified that no life can live in them!

Deforestation  Population growth leads to the loss of natural habitats  Cut down trees to build new homes  Loss of biodiversity  Loss of oxygen producers and CO 2 eliminators

Herbicides and Pesticides  We spray pesticides and herbicides with out knowing the consequences  DDT - (dichloro- diphenyl- trichloroethane) –Used to combat Malaria, Typhus, other insect borne diseases

DDT  Claimed to be a miracle  No effect on humans  Can build up in the environment –Biological magnification

Human health impacts of pesticidal pollution  Affect and damage the nervous system.  Cause liver damage.  Damage DNA and a variety of cancers  Cause reproductive and endocrine damage.  Cause other acutely toxic and chronic effects.

Bioaccumulation of DDT  Accumulated to such levels in top predators that it started having lethal effects.  Endangered many species of birds, Including our Bald Eagles.

Ozone depletion  In the ’80’s it became apparent that the ozone layer was disappearing  It was confirmed that is was directly caused by human activity

CFC’s  Chloro-Fluoro-Carbons  Aerosols - leaking into the atmosphere and eating away the ozone  Freon is also a CFC

Global Warming  Increase in CO2  Increase in greenhouse effect  Increase in global temperatures

Pollution  Water Pollution –Nutrient loading – runoff from fertilization = eutrophication –Affects drinking water –Oil Spills –Gasoline spills

Exxon Valdez

BP – Gulf Coast

Biodiversity

Threats to Biodiversity Habitat loss and destruction Alterations in ecosystem composition Introduction of exotic species Over- exploitation pollution and contamination Global climate change

Who dominates the earth? Estimates of total number of species: (some taxa may be much higher.) million insects 5-10 million bacteria 1.5 million fungi ~1 million mites