HUMAN CAUSED HAZARDS AND DISASTERS

Unit III – Chapter 5

WHAT ARE THEY?1. Global Warming2. Ozone Depletion3. Loss of Biodiversity4. Destruction of Ecosystems

Deforestation Desertification Introduction of New Species

WHAT ARE THE CHARACTERISTICS? They affect people in many parts of the

world Their effects are long term – they

remain a threat for many years They cause permanent damage or

serious contamination to the environment

1. GLOBAL WARMING Most serious UN’s International Panel on Climate

Change – noted continuous warming of climate

Continuous warming is caused by humans (summer temperatures in Ontario in 2010 were 2 degrees higher than normal)

Signs: decrease in thickness of Arctic ice cap

WHY SHOULD WE BE CONCERNED? Sea levels will rise by as much as 1 m because of

melting glaciers YouTube - Melting Trends: Arctic Ice Completely Gone by 2020?

Rainfall and temperature patterns will shift = change in agricultural areas and loss of biodiversity

More violent and more intense weather Deforestation due to lack of water Deserts will enlarge Permafrost areas will melt Significant drop in food production – higher

temperatures and desertification

2. OZONE DEPLETION Oxygen makes up about 20% of Earth’s atmosphere It is essential to life on Earth Ultraviolet UV radiation is found about 25 km above the

Earth’s atmosphere (here to Sackville) UV rays split Oxygen into its two separate atoms Free atoms combine with oxygen molecules to form ozone Ozone layer is important because it blocks out radiation

that damages cell structure Normally there is balance A 1% reduction in the ozone layer leads to a 2 to 4%

increase in melanoma

THE HUMAN EFFECT ON THE OZONE In 1930s chemical compounds containing chlorine, fluorine and

carbon were created – chlorofluorocarbons (CFCs) Used in aerosol cans, refrigeration systems, air conditioners Stable – very difficult to break down BUT – because of this, they stay in the air for a long time Then they rise up into stratosphere where they are broken

down and release chlorine atoms The chlorine atoms react with the ozone and break it down into

chlorine oxide (CIO) and O2 – thus thinning the ozone layer Result - Holes are appearing in ozone layer Example -

Ozone hole over Antarctica is now a little larger than North America

EFFECTS OF OZONE DEPLETION More UV rays are allowed to reach earth Effects:

Cataracts Skin cancer Suppression of the immune system in

animals and humans Damages plants – affects photosynthesis

and growth Damages phytokplankton - affects Earth’s

oxygen supply

3. LOSS OF BIODIVERSITY Biological diversity – refers to variety of

life forms on Earth 1.8 million species have been identified

– many more exist Diversity described at three different

levels1. Genetic2. Species 3. Ecosystem

GENETIC DIVERSITY Refers to various genetic information

that distinguishes species Manipulation of this genetic materials

allows the production of variety of grasses and grains

SPECIES DIVERSITY Describes various life forms that

appear in a particular area

ECOSYSTEM DIVERSITY Indicates different habitats,

environments or biological communications that appear in given areas – i.e. coral reefs, deserts, ponds, tropical forest

Each provides a habitat for a particular species

Habitat destruction is one of the main threats to biodiversity on Earth

WHY IS IT IMPORTANT? We depend on plants and animals for our survival Much of the world economy depends on making

use of biodiversity Other reasons: Without plant diversity around the world, the

balance within the atmosphere would be disrupted Agricultural production would not be possible

without different species of birds and insects Ecosystem stability would collapse without

species diversity

HOW IT IS LOST1. Eliminates the various species of plants and

animals that live there Cascading effect - The disappearance of

one species affects all around it i.e. if a specific plant disappears, the insects that feed off it are affected, and the birds that feed off the insect are at risk

Introduction of a new species of plant or animal into an area also threatens biodiversity – Refireproofing of Florida

4. DESTRUCTION OF ECOSYSTEMS Deforestation Forests are important for fuel, building materials, food and medicinal

products Humans viewed forests as a constant With loss of forests:

Increased flooding - Landslides, mudslides Soil erosion Increase in wildfires Increase in carbon dioxide from burning plus removal of carbon

dioxide from the atmosphere by plants/trees lost Global Consequences

Loss of biodiversity for the area Loss of living space and therefore culture Increased global warming

Desertification Desertification threatens nearly 1/3 of land

surface It occurs when productive dry land is

degraded to the point that it becomes unproductive desert

Causes: Over-cultivation Overgrazing Deforestation Inappropriate irrigation

CASE STUDY OVERVIEW: DESERTIFICATION IN THE SAHEL

A region of grassy plain along the southern edge of the Sahara Desert

Covers 2.5 million square kilometres Includes the following countries:

Mauritania, Senegal, Mali,

Burkina Faso, Niger, Chad, Nigeria, Sudan, Ethiopia,Somalia (Foundation for

Sustainable Agriculture, 2010)

THE SAHEL Despite 40 years of tree planting, land-

use modification and education programs – still a problem

Main Causes for Desert Advancement Fragile natural environment Agricultural practices Population growth

THE NATURAL ENVIRONMENT Most fragile ecosystem in Africa Hot, dry climate

60 and 100 mm per rain / year Nova Scotia 1260 to 1600 mm per rain / year Falls only three months a year Nova Scotia precipitation expected every month Droughts are common Nova Scotia – rare High temperatures – 40°C to 42°C Nova Scotia 5°C to 7°C

Sandy soil thin, susceptible to damage, slow to recover, easily eroded

Vegetation Annual grasses with isolated trees and shrubs

AGRICULTURAL PRACTICES Originally people lived as nomads

Kept small herds of animals Rotated crops Each crop area was allowed to restore fertility for about 10 years

During 1950s and 60s Farmers moved from south where they were having lots of rain to north Started cultivating cash crops Required heavier land use Improved vet care and creation of more watering holes for animals led to

increase in size and number of herds More land clear cut for farming, grazing an firewood This situation depended on high rain falls for sustainability

Droughts came from 1968 to 1973 and again in the 1980s 1990s rainfall occurred again with devastating results

Flooding, followed by disease Rapid plant growth from rainfall increase insect population – grasshoppers

killed more than 19 million hectares of land

POPULATION GROWTH In 1996 – population estimated at 247 million Canada’s population approximately 34 million Annual population growth = 3% In Canada – 1.3% Population increasing but arable land declining Has led to greater degradation of land Hundreds of villages abandoned Thousands have died More have suffered malnutrition – 859,000

children alone – most in Chad and Niger

NEW SPECIES INTRODUCTIONLamprey Eels Introduced into St. Lawrence Seaway Lampreys are parasitic fish that latch on to

other fish and kill them Had no natural enemies in the Great Lakes so

flourished Threatened several species of fish and

completely wiped out lake trout Scientists helped control numbers but could not

eliminate them

Purple loosestrife Vigorous and aggressive growth Introduced as an ornamental flower Now threatens wetlands Thick and matted root system Dries out land

Hog Wild In 1539 Spaniard Hernando de Soto brought pigs from Spain to

Florida Some escaped into Florida swamps and multiplied Only natural enemy was Florida panther which was on endangered

list while pigs multiplied Damage ground and plants with sharp tusks and canine teeth

(rooting) Damage by wallowing in Everglade water which destroys

vegetation Voracious eaters – eat almost anything including salamanders,

snakes, newts, worms, snails grubs and even small deer; also alligator and bird eggs

Aggressively efficient reproducers – a sow can breed 2 litters a year – each litter has about 6 piglets.

In turn these piglets are sexually mature by 6 to 12 months To control pigs – hunting and trapping is encouraged

Chapter 6

POLLUTION AND WASTE DISPOSAL

POLLUTION Any material or product produced by

humans and disposed of in such a way that it interferes with the health of our world – living organisms, environments and natural processes of Earth (Global Connections, 1999)

TYPES OF POLLUTANTSA. Persistent – remain in the environment

for many years without breaking downB. Non-persistent – biodegradable

pollutants

Two main types:Primary

Secondary

AIR POLLUTION

PRIMARY AIR POLLUTANTS Carbon dioxide

fossil fuels when burned, release CO2 into the atmosphere Carbon monoxide

burning fossil fuels are not completely oxidized Odorless Colourless poisonous

Hydrocarbons organic compounds that contain carbon and hydrogen waste from production exhausts from factories Cause smog Respiratory problems

Particulates Tiny pieces of solid material dispersed into atmosphere from production Dangerous – act as centers that collect hazardous gases and chemicals Can cause respiratory difficulties Carcinogenic Chief source = smoke Other sources

bits of asbestos and insulation fibers dust particles from construction, mining and demolition

Sulphur dioxide Burning fossil fuels – factories and power plants Reacts with water, oxygen and other chemicals = sulphuric acid Odor and irritation to throat and lungs

Nitrogen oxide Burning fossil fuels Combustion in atmosphere – nitrogen and oxygen combine Harmful to respiratory system

SECONDARY AIR POLLUTANTS Form when primary air pollutants react

with one another1. Smog2. Acid Rain

SMOG Industrial and photochemical smogIndustrial: Build up of particles, smoke and dust released into atmosphere from

manufacturing Were common in MDCs Emission controls put in place which has lessened but not removed

this Now common in LDCs Manufacturing moved to LDCs No emission controls in placePhoto-chemical: Forms over urban centres on hot calm days Nitrogen oxides and hydrocarbons combine to form ozone and PAN

(see Figure 6.4, pg. 133 – Global Connections)

ACID RAIN AND ACID DEPOSITION Oxides containing sulphur and nitrogen

released into atmosphere from burning of fossil fuels and manufacturing

Dissolve in cloud droplets and fall to Earth as rain

Can move through atmosphere and effect areas far from site of manufacturing – i.e. manufacturing done in Eastern US affects Nova Scotia – acid deposition

EFFECTS OF ACID RAIN AND DEPOSITION Contact damages plans Affects soil which in turn affects root

systems of plants Pollutes rivers – kills fish stocks Loons in Kejimkujic Lake in NS – have high

levels of mercury because they feed on contaminated fish

Corrodes buildings, roofs and cars Increase respiratory problems – asthma

Once thought to be nature’s cleaning system capable of absorbing and purifying waste

WATER POLLUTION

RIVERS, LAKES AND OCEANS Rivers are being polluted by human and

toxic industrial waste Example: Danube Lakes and inland seas – susceptible

because they lack outflows and currents to dilute or remove pollutants

Often receptors for rivers that dump waste Oceans are destinations for rivers bringing

with them toxic and human waste

WATER POLLUTION HAZARDS Disease causing bacteria, viruses and protozoa

cause cholera, dysentery and hepatitis Too much nitrogen and phosphorous causes

excessive algae growth – blocks light to deeper water

Sediment caused by erosion suffocates fish, plants and other organisms

Oil spills kills seabirds, fish, and aquatic animals Synthetic compoounds and heavy metals are

extremely toxic to many life forms

EVIDENCE OF WATER POLLUTION

Algae growth Fish kills Floating aste Oil slicks Foul odours Beach closures

WASTE DISPOSAL

TYPES OF WASTE Domestic sewage Solid waste Toxic and hazardous waste

DOMESTIC SEWAGE Produced from homes and commercial buildings Through sinks, toilets, showers and bathtub drainsTreatment: Most often dumped directly into rivers, lakes and

oceans Municipalities treat sewage by removing solids and

most organic materials Aerate the sewage to kill bacteria and allow micro-

organisms to decompose solid waste – sludge Some sludge is dried and used in fertilizers No method removes toxic chemicals

SOLID WASTE Majority is from packaging Paper, plastic, metal, glass and

styrofoamDisposal:

Burying Incinerating Recycling

LANDFILLS Early landfills Unslightly dumps Breeding grounds for disease Smell Leeching Current landfills Designed to eliminate above problems Problems: finding adequate space and

NIMBY

INCINERATION Advantages:

Reduces the volume of waste Heat can be used for electrical or

heat generation Disadvantages

Increased amounts of carbon dioxide

Release of toxic chemicals into the air

RECYCLING REDUCE – most important – cut down

on consumption REUSE RECYCLE

TOXIC AND HAZARDOUS WASTE Live in chemical age Pesticides, herbicides show up in

drinking water People living near dumps sites have

higher rates of cancer, congenital defects and other disabilities

Chemical spills kill life

WHAT IS HAZARDOUS VS TOXIC WASTE?

Waste that has dangerous properties that when activated become toxic (poisonous)

Inflammable Explosive Chemical

HOW DO MDCS DISPOSE OF HAZARDOUS WASTE?

Dump into sanitary landfills thus contaminating them Discharge untreated waste into sewers, streams,

rivers and lakes High pressure injection to force waste into deep wells Store liquid waste or sludge in surface pits, ponds or

lagoons Place solid waste in specially designed dumps Cover waste with soil Store in special containers in abandoned mines or

caverns Send it to LDCs for disposal

HAZARDOUS WASTE DESTRUCTIONThermal Burn waste in furnaces where the heat can be raised to a very high

temperature Costly Must ensure fumes don’t escape Disposal of toxic ash is problem

Neutralization Waste can be neutralized through another type of reaction

Acidic waste can be treated with an equally strong alkaline solution

Micro-organisms can break down some toxic substances (bacteria digest oil spills)

Waste produced by one industry can be used by anotherOnly true solution is reduction

WASTE ON FILM The Story of Stuff The Trail of Trash Holiday Waste

REFERENCES http://visual.merriam-webster.com/images/plants-gardening/plants/plant/photosynthesis.jpg,

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a13addc07e&furl=http%3A%2F%2Flibrary.thinkquest.org%2FC003124%2Fimages%2Ftides.jpg March 3

http://www.harcourtschool.com/activity/science_up_close/314/deploy/interface.html March 3 file:///H:\My%20Pictures\Hurricane_formation.gif retrieved March 11 file:///H:\My%20Pictures\flappy_tornado_formation.jpg retrieved March 11 http://www.bing.com/images/search?q=global+warming&FORM=BIFD#focal=9da80adaf076

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http://www.youtube.com/watch?v=vhrWCGIlku4 retrieved January 6, 2011. http://www.syngentafoundation.org/db/1/49.gif&imgrefurl retrieved January 6, 2011. http://postconflict.unep.ch/galleries4.php?key=desertification retrieved January 7, 2011 http://kasms.blogspot.com/2009/06/shit-me-lamprey-eel-mouths-are-cool.html– retrieved

January 7, 2011 http://www.spiderchainoflakes.org/projects.html retrieved January 7, 2011 The Story of Stuff retrieved February 5, 2011 from thestoryofstuff.com