Transcript Human Impact on the Environment

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 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
 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 CO2 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 CO2
eliminators
Herbicides and Pesticides
 We spray pesticides
and herbicides with out
knowing the
consequences
 DDT - (dichlorodiphenyltrichloroethane)
– 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
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.)
•10-30 million insects
•5-10 million bacteria
•1.5 million fungi
•~1 million mites