Hazardous Earth Flashcards
How does air move at the equator?
Air rises up
What is the normal weather conditions at a high pressure belt?
Low rainfall, often cloudless skies`
How does atmospheric circulation distribute heat energy from the equator to the poles?
The sun heats the earth at the equator causing air to warm up and rise. As the air rises it cools and moves away. The cool air sinks and some is drown towards the poles as surface winds
What are the theories about the causes of natural climate change?
The eruption theory
Asteroid collisions
The sunspot theory
The orbital theory
What is the eruption theory?
During big volcanic eruptions, ash and gas can block some sunlight reaching the Earth’s surface. This cools the planet and lowers the temperature
How can asteroid collisions cause natural climate change?
Large asteroid collisions would blast millions of tonnes of ash and dust into the atmosphere and cool the climate as the sunlight would be blocked.
What is sunspot theory?
These are black areas on the sun’s surface. Lots of spots means more solar energy being fired out from the sun towards the earth increasing the temperature
What is the orbital theory? (sometimes called Milankovitch cycles)
Changes in the earth’s orbit affect where sunlight falls on Earth
What is the difference between weather and climate?
Weather is the day to day conditions e.g. raining, snowing, sunny whereas climate is the average conditions for a time of year e.g. autumn, winter
What evidence is there for past climates?
Fossilised plants, animals and pollen that no longer live in the UK
Ice cores
Tree rings
Landforms like U shaped valleys
How do ice cores tell us about past climates?
Trapped in ice layers are air bubbles which contain carbon dioxide. Scientists measure the amount of carbon dioxide
How do tree rings tell us about past climates?
Each ring on a tree is a year’s growth. Scientists examine tree rings to learn about past climate conditions.
What are the greenhouse gases?
Carbon dioxide
Methane
Nitrous Oxide
What is the enhanced greenhouse effect?
Pollution of the atmosphere with carbon dioxide
What is thermal expansion?
The sea expanding as it warms
By 2100, estimates predict temperature will increase by how much?
Between 1.1 and 6.4 degrees Celsius
By 2100, estimates predict sea levels will rise by how much?
30cm and 1m
Why is predicting future global warming difficult?
We don’t know what the future population will be, whether fossil fuels will continue to be used or if people will change their lifestyles and recycle more or use public transport
What are the impacts of climate change?
More frequent floods, droughts and heatwaves.
Stronger storms and hurricanes
Changes to farming as they adapt to new climates
Climate refugees as people evacuate low lying places that are no longer habitable.
What are the different names for tropical cyclones?
Hurricane
Cyclone
Typhoon
What is the Saffir-Simpson Hurricane scale?
5 different categories to measure wind strength
Name the features of tropical cyclones?
Circular shape
Hundreds of km wide
Eye at the centre of the cyclone
In the eye, pressure is low and winds are light
Eye wall surrounds the eye
The eyewall have strong winds, torrential rain and a low temperature
What measurement is used to give the category rating of a cyclone?
Wind speed
What is needed for a tropical cyclone to form?
Warm ocean with temperatures above 26.5degrees Strong winds (to move the cyclone)
What are the physical hazards of tropical cyclones?
High winds Intense rainfalls Storm surges Coastal flooding Landslides
Identify the ways tropical cyclones impact people?
Buildings destroyed
Roads damaged
Electricity supplies damaged
Describe the impacts tropical cyclones can have on the environment
Trees may be uprooted by high winds
Beaches may be eroded by storm surges
Coral reefs may be damaged by storm surges
Harmful chemicals may pollute the environment
How can we work out the predicted paths of cyclones?
Satellite photos
Computer models
Weather forecasting technology
Is the air pressure high or low during a tropical cyclone?
Low
Give an example of a tropical cyclone in a developed country
Hurricane Katrina, New Orleans, USA
Give an example of a tropical cyclone in a developing country
Typhoon Haiyan, Philippines or Cyclone Nargis, Myanmar
How can we prepare for tropical cyclones?
Weather forecasting Satellite technology Warning Systems Evacuation strategies Storm surge defences
What are the 4 layers of the earth?
Inner Core
Outer Core
Mantle
Crust
What is the lithosphere?
The uppermost layer of the Earth. It includes the very top of the mantle and the crust.
Describe how continental crust is different from oceanic crust
Continental crust is thicker
Continental crust is less dense
Explain how convection currents cause tectonic plates to move
The core heats the mantle causing the mantle to rise. As it rises it begins to cool and falls again in a circular motion. As the tectonic plates sit on top of the mantle, the circular motion causes the plates to move.
What are the different plate boundaries?
Conservative
Divergent
Convergent
What happens at a conservative plate boundary?
Two plates slide past each other creating earthquakes
What happens at a divergent plate boundary?
Two plates move apart creating small earthquakes and not very explosive/dangerous volcanoes
What happens at a convergent plate boundary?
Two plates collide creating large earthquakes, explosive volcanoes with the potential for tsunamis.
What is a collision zone?
A type of convergent plate boundary creating mountain ranges such as the Himalayas. Earthquakes can also happen.
What is subduction?
When oceanic crust sinks into the mantle at a convergent plate boundary.
What are the different shapes of volcanoes?
Shield volcanoes
Composite volcanoes
Explain how earthquakes are caused at convergent plate boundaries
Tension builds up as one plate get stuck as it moves down past the other into the mantle. The plates eventually jerk past each other sending our shock waves.
What is the Richter scales?
A scale from 1-9 which measures the power of an earthquake MAGNITUDE!
Where is the focus of an earthquake?
The point in the crust where the earthquake starts
Where is the epicentre of an earthquake?
The point on the earth’s surface above the focus
If the focus of an earthquake is shallow what is the earthquake like?
More destructive
Give an example of an earthquake in a developed country
Sendai, Japan, 2011
Give an example of a tropical cyclone in a developing country
Port-au-Prince, Haiti, 2010
How can people prepare for earthquakes?
Earthquake drills
Emergency kits being prepared at home
Earthquake proof buildings where gas supplies cut off to reduce the risk of fire
What is the Volcanic Explosivity Index (VEI)?
It measure the destructive power of volcanoes on a scale of 1 to 8.
What are primary effects?
Effects which are caused instantly
What are secondary effects?
Effects which happen in the hours, days and week after the event
What are the hazards produced by volcanoes?
Pyroclastic flows Landslides Lava flows Lahars (volcanic mudslide) Lava bombs Ash fall
What are the benefits of volcanoes?
Creates fertile land suitable for farming
Hot springs can create tourist attractions
How can we predict volcanoes?
Seismometers to measure the earthquake tremors which increase as magma rises
Boreholes to measure water temperature as magma heats it up
Tiltmeters to detect when the volcano swells as it fills with magma
Aircrafts to measure the amount of gas given off
Why are people in the developing world at a greater risk from hazards than those in developed countries?
They build in risky location because there is nowhere else affordable to live
They can’t afford safe, well built houses
They don’t have insurance
Their governments don’t have the money and resources to provide aid
Communications are poor so warning and evacuation may not happen
What is a refugee?
People who are forced to move due to natural hazards or war
What is aid?
Aid is help given in an emergency.
