1. Meteorological and Hydrological Hazards

2. Vocabulary
The Equator: an imaginary line that separates the world into a northern and southern have
Saffir-Simpson Scale: scale from 1 to 5 that measures a hurricane’s force
Greenhouse effect: the warming of the layer of air surrounding the Earth due to pollution
Urbanization: the movement of the population into city life
Deforestation: the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use. 

3. Meteorological Disaster: Hurricanes
Hurricanes are also called severe tropical cyclones or typhoons
They are exceptionally strong tropical storms
These storms develop along the equator.
They are giant whirlwinds that are 100 to 500 kms wide
They occur when the temperature at the waters surface rises above 26 degrees Celsius and wind speeds exceed 117 km/h

4. Saffir- Simpson Scale

5. Hydrological Hazards: Floods
Floods are natural disasters that occur when rain is both heavy (50-70 mm/h) and continuous(over 200 mm in 24h)
This causes and unusual rise in water levels
Flooded streets make it difficult for rescue workers to reach victims and transport supplies
The force of the water destroys fragile buildings and damages property

6. Natural Hazards and Humans
During the 1990’s the centuries highest temperatures this century were recorded
During the summer of 2003 an unusual heat wave swept through Europe killing people. Mostly the elderly and the sick
Since the end of the 1960’s snowfall has decreased by percent
Since 1980 the Arctic has lost almost 10 percent of its layer of sea ice
Since the end of the 19th century the Earth has warmed by 0.4 to 0.8 degrees and sea levels have risen to cm

7. Major cause 1: Greenhouse Gases
Three main gases lead to the greenhouse effect
Carbon Dioxide: from burning fossil fuels
Methane: gas leaks, pig farms and decomposing waste materials
Chlorofluorocarbons: used in refrigerators, air conditioners and aerosol cans
Most scientists believe that humans must decrease the use of these gases
If they don’t these gases can cause major weather upheavels such as hurricanes, flooding and drought which could be bad for life on earth

8. Cause 2: Urban Development
Environmental modifications and development along coastal areas are increasing the risk of flooding
Water proof asphalt and buildings allow the water run off during rain fall, and less trees in the cities mean the water is not absorbed allowing water to rise quicker
Highways act as canals and allow floods to spread further and faster than before by changing their natural pathways

9. Cause 3: Deforestation
Deforestation modifies the water cycle by changing the soils capacity for absorbing and storing water
Deforestation increases the risk of landslides