Hazardous Earth Flashcards
Describe the movement of ocean current
Cold salty and water sinks at the poles then it flows towards the equator and it’s warmed again, creating a convection current
What are the pressure differences on Land
Land
Heat quickly in summer and cools quickly in winter
Heats air above it,air become lighter and rises
Generally formes areas of low pressure in summer and high pressure in winter
What are the pressure differences on sea
Takes longer to heat and cool so the air is dense and cool in the summer
Forms high pressure in the summer and low pressure in winter
What’s the intertropical convergence zone (ITCZ)
Occurs near equator between two Hadley cells where warm tropical air converges at the equator.sun radiation most intense causing air to rise rapidly, creates area or low pressure brings heavy rainfall,as air moves away from equator it looses moisture and density ,descending to form arid zones
What are the 4 main theories that climate change occurs in the past
Eruption theory-eruptions produce ash that rises into stratosphere,reflecting back sunlight cooling planet
Asteroid collision theory-asteroid hit earth tonnes dust,ash into atmosphere,blocking sunlight cooling planet
Sunspot theory,lost if sunspots means more solar energy warming planet
Orbital change-earth orbit changing ,affecting amount of estimation earth receives this tilt also ,can affect seasons
What sources tell us about oast climates
Ice cores -air bubbles contain co2 that tell his about previous warm and cold periods
Tree rings- each ring shows a rings growth,in warmer and wetter years tree grew more
Historical sources,drawings diaries or newspapers
What is the enhanced greenhouse effect
Way human activities (industry,transport energy) produce greenhouse gasses that trap heat from the sun and warm planet
How has the enchanted greenhouse effect been measured
Near 1*c rise in average temp
Sea levels risen over 200mm(thermal expansion)arctic sea ice have halved since 1980
90 of worlds valleys glaciers are shrinking
What could climate change causes
More frequent storms and droughts
Stronger strom
Changed to farming(unreliable rainfall)
Climate refugees to low lying areas
What is an tropical cyclone
Rotating system of clouds and storm
Forms over tropical waters 26.5degrees
Has winds which can exceed 118km/h
What factors do cyclones need to form
A warm ocean exceeding 26.5degrees
Creates a warm body of air to develop
Strong wind that draw the air up rapidly from ocean surface
A strong coriolis force created by earths rotation
What hazards do cyclones bring
Strong winds-bring downs tree and power lines
Strom surges -bring flooding owing to low pressure
Intense rainfall- is flood risk
Landslides -saturated hills can slump
Why is Bangladesh vulnerable to cyclones
Much of population is rural
Urbanisation means increases surface runoff , mroe rainwater reaches rivers
Unplanned settlements have been built on low lying land prone to flooding
It’s GDP is low so it’s less able to invest in costly flood defences
He does Bangladesh attempt to protect population for cyclones
Forecasting (issued through tv and radios)
Satalitle technology to track cyclones
Warning system evacuation strategies and storm defences ( embankments)
Primary and secondary impacts form cyclone Alia
Primary-killed 190 people and made 750000 people homeless
Secondary crops being destroyed farm animals being killed, sickness spread from contaminated water
