Hazardous Earth Flashcards
What creates a low and high pressure belt?
At the equator the sun warms the Earth, which transfers heat to the air above causing it to rise, creating a low pressure belt. As the air rises, it cools and condenses forming clouds and rain. The cool air sinks, creating a high pressure belt with cloudless skies and very little rainfall
What are ocean currents?
Large scale of movements of water that transfer heat energy from warmer to cooler regions
How is heat transferred by ocean currents?
Surface currents are caused by winds and help transfer heat away from the equator.
Name the four natural causes of climate change?
Orbital changes
Volcanic activity
Solar output
Asteroid collisions
Orbital changes
Eccentricity - orbit of the earths shape has changed over long time. Meaning sometimes the Earths orbit around the sun is circular, making us a little warmer. Sometimes the Earths orbit becomes more elliptical, making the earth cooler
Tilt - North and South Poles are not exactly aligned at the top and bottom of the Earth. They are 23 degrees tilted, which create our seasons
Precession (wobble) - as the earth rotates it wobbles, this creates big or small difference between a summer or winter
Asteroid collisons
They are large cosmic material which could impact the earths surface. Producing large amounts of dust in the atmosphere and block sunlight leading to glacial periods.
Volcanic activity
They produce ash, sulphur dioxide gas. They can spread around the atmosphere. Ash can block sunlight and cool the earth.
Solar output
Astronomers recorded sunspots over 2000 Years ago. The sunspots. They tell us how active the sun is.
Evidence for natural climate change comes from many sources. Name them.
Tree Rings
Ice cores
Historical sources
Tree rings
Each ring shows a hear of growth. Changes in shape and size of tree rings can show conditions during that year. Bigger tree rings mean warm weather, thinner tree rings mean colder weather
Ice cores
Ice contains bubbles of the air from each year. Scientists analyse bubbles in each layer to see how much Co2 they contain. They can learn about temperatures by measuring relative amounts of different types of oxygen atoms in the water
Historical Sources
Old photos, drawings, written records, diaries. Often not accurate because they were not intended to recored climate. However they can give us some evidence of recent climate trends
What are the human activities making the greenhouse effect stronger?
Farming
Industry
Energy
Transport
How is Farming enhancing the greenhouse effect?
Live stock produce a lot of methane
Trees absorb and store Co2. When land is cleared of tree for agriculture it stops absorption of Co2, which leaves more Co2 in the atomosphere.
How is Industry enhancing the greenhouse effect?
Industry uses a lot of energy. Industrial waste may end up in landfill sites where it decays, releasing methane
How is energy enhancing the greenhouse effect?
Co2 is released into atmosphere when fossil fuels like coals, oil and natural gas are burnt
How is Transport enhancing the greenhouse effect?
Most cars, lorries, ships and planes run on fossil fuels, which release greenhouses gases when burnt. Car ownership increasing in countries developing meaning more cars, more congestion meaning engines running longer.
What evidence is there that human activity is causing climate change?
Declining Arctic Sea
Sea Level Rise and Warming Oceans
Global Temperature rise
Extreme weather events
Climate changes have serious impacts on people
Less crops could increase malnutrition, ill health and death from starvation, particularly in lower latitudes.
Death due to heat
Some areas could become hot and dry and difficult to inhabit
Features and structures of tropical cyclones
The centre of the cyclone is called an eye. The eye is surrounded by the eye wall, where there is strong winds. Towards the edge of the cyclone the wind speeds fall, clouds become smaller and more scattered, the rain becomes less intense and temperature increases.
What physical hazards are caused by tropical cyclone?
High winds Storm surges Intense rainfall Land slides Coastal flooding
What impacts does physical hazards have on the environment?
Trees are uprooted by high winds which can damage or completely destroy wooded habitats.
Storm surges can erode beaches and damage coastal habitats
When experiencing a cyclone some countries may be more vulnerable than other. Name physical vulnerabilities.
Low lying coastlines are vulnerable to storm surge flooding as well as large waves caused by the high winds.
Areas in the path of the tropical cyclones hit more frequently
When experiencing a cyclone some countries may be more vulnerable than other. Name economic vulnerabilities.
Many people depend of agriculture which is often badly affected - leads to loss of livelihoods
People may not have insurance to cover the costs of repairing damage cause by cyclones
When experiencing a cyclone some countries may be more vulnerable than other. Name social vulnerabilities.
Buildings are poorer quality so more easily damaged
Little money for flood defences or training emergency teams
Harder to rescue people because of poor infrastructure
Name the strategies used to prepare for and respond to tropical cyclones
Forecasting - when and where tropical cyclones will hit land can be predicted. Scientists can use it to monitor cyclones and calculate a predicted path for cyclone.
Evacuation - warning strategies used to alert people to a tropical cyclone. Alert will go off to warn people and give them to protect homes and businesses. Reduce deaths and injuries
Defences - defences can be built along coast to prevent damage from storm surges. Buildings can be designed to withstand a storm surge. This will number of buildings destroyed, so less people injured
What is at the centre of the Earth
The core, which is a ball of solid and liquid
Arid zone
Sinking air from Hadley and Ferrel cells meeting causes high pressure and prevents rainfall. Rainfall is very low for all or most of the year. Temps are hot or warm.
Polar zone
Sinking air from the Polar Cells create an area of high pressure at the poles. Temperature are low all year round. Temps are low all year round and there’s very little rainfall.
Tropical zone
Rising air from the two Hadley cells meeting causes low pressure and lots of rainfall. Temps are hot all the time and rainfall is high.
How do tropical cyclones develop?
Develop when sea temp is 26..5 degrees or higher and when the wind shear between higher and lower parts of the atmosphere is low. Most cyclones is between 5 and 30 degree north and south of equator - any further and the water isn’t warm enough. Warm, moist air rises and condensation occurs. Releases huge amounts of energy, which makes the storm powerful. Rising air creates an area of low pressure, which increases surface winds. Earths rotations deflects the paths of the winds, which causes the cyclone to spon.
What is the centre of the cyclone called?
The eye - its up to 50km across and is caused by descending air. There’s very low pressure, light winds, no clouds, no rain and high temp in eye.
What is the eye surrounded by?
By the eye wall - there’s spiralling rising air, very strong winds, storm clouds, torrential rain and a low temp
What happens towards the edges of the cyclone ?
Towards the edges of the cyclone the wind speed falls, the clouds become smaller and more scattered, rain becomes less intense and temp increases
What physical hazards are caused by tropical cyclones?
High winds - windspeed can reach 250kmph
Intense rainfall - rain gets heavier as you get closer to the eye
Storm surge - large rise in sea level caused by low pressure and high winds.
Coastal flooding - flooding happens as a result of storm surges and strong winds drive large waves onto the shore.
Landslides - heavy rain makes hills unstable, causing landslides
What is at the centre of the Earth?
At the centre of the Earth there is a core
The core is a ball of solid and liquid iron and nickel
Centre very dense and becomes less dense as you come out
Temp inside the core ranges from 4400-6000 degrees
What is around the core?
Is the mantle - made up of Silicon-based rocks
The part of the mantle nearest to the core is Quite rigid
The layer above this, called aestonosphere, is semi molten
Very top bit of mantle is rigid
Temp 1000 and 3700
What is the solid outer layer of the earth called?
Called crust - made of silicon based rocks
What are the two types of crust?
Continental crust is thicker and less dense
Oceanic crust is thinner and more dense
What causes convection currents?
Lower parts of the asthenosphere heat up they become less dense and slowly rise.
As they move towards the top of the asthenosphere they cool down, become less dense, slowly sink.
These circular movements of semi molten rock are called convection currents
Whats cause tectonic plates to move?
Convection currents in the asthenosphere create drag on the base of tectonic plates - and this causes them to move
What are the three plate boundaries?
Convergent boundaries
Divergent boundaries
Conservative boundaries
Describe convergent boundaries?
Where two plates move towards each other.
When an oceanic plate meets a continental plate, the denser oceanic plater is forced down into the mantle and destroyed. Creating volcanoes and ocean trenches.
When two oceanic plates meet, the plates collide, and the ground is folded and forced upwards to create mountain ranges.
Describe divergent boundaries?
Where two plates move away from each other. Magma rises from mantle to fill the gap and cools, creating new crust.
Describe conservative boundaries?
Where two plates are moving sideways past each other, or are moving in the same direction but at different speeds. Crust isn’t created or destroyed.
At what boundaries are volcanoes found at?
Convergent and divergent boundaries
What happens at convergent plate boundaries during volcanoes?
At convergent plate boundaries the oceanic plate goes under the continental plate because its more dense, it’s melted and destroyed here. A pool of magma forms, the magma rises through cracks called vents. The magma erupts onto the surface forming a volcano.
What happens at divergent plate boundaries during volcanoes?
Magma rises up into gap created by plates moving apart, forming a volcano
Where are hotspots found?
Away from plate boundaries
Some volcanoes form in the middle of tectonic plates hotspots.
They occur where a plume of hot magma from the mantle moves towards the surface, causing an unusually large flow of heat from the mantle to the crust.
What are the two different volcanoes?
Composite and shield volcanoes
What is composite volcanoes?
Occur at convergent plate boundaries
They have explosive eruptions that start with ashy explosions that deposit a layer of ash.
Lava cant flow
What is shield volcanoes?
Occur at hotspots or divergent plage boundaries.
Not explosive and are only lava
Flows quickly and spreads over a wide area, forming a low, gentle-sided volcano.
Describe an earthquake occurring at convergent boundaries
Tension builds up when one plate gets stuck as it’s moving down past the other into the mantle
Describe an earthquake occurring at divergent boundaries
Tension builds along cracks within the plates as they move away from each other
Describe an earthquake occurring at conservative boundaries
Tension builds up when plate gets that are grinding past each other get ctuck
What are shallow-focus earthquakes?
Caused by tectonic plates moving at or near the surface. They have a focus between 0 and 70km
What are deep focus earthquakes?
Caused by the crust that has previously been sub ducted into the mantle moving towards the centre of the earth, heating up or decomposing. They have a focus between 70km and 700km below the earths surface.
What can cause a tsunamis?
Tsunamis are a series of enormous waves caused when huge amounts of water get displaced. Underwater earthquakes caused the seabed to move, which displaces water. Waves spread out from the epicentre of the earthquake.
Name some methods for predicting earthquakes.
- lasers can be used to detect the movement of tectonic plates before an earthquake
- Rocks will crack and expand because of the increased pressure just be fore and earthquake
- scientists can measure gases that escape from cracks in the crust just before an earthquake
Name some methods for predicting volcanoes.
- Volcanic eruptions can be predicted if the volcano is well-monitored to look for the tell-tale signs that come before a volcanic eruption
- thermal imaging cameras can be used to detect changes in temp around the volcanoes. Temps increase before an eruption.
- scientists can analyse the gases escaping from a volcano. Volcanoes emit lots of sulfurous gases before an eruption.
Earthquake in Japan
Buildings were built with deep foundations, strict building laws help prevent major damage during an earthquake
Facts on Hurricane Katrina
USA had sophisticated monitoring system to predict if a hurricane will hit, they issued a hurricane warning, 70-80% of New Orleans Residents were evacuated, the city New Orleans were badly damaged - flood defences that were supposed to protect the city failed, caused flooding. Coastal habitats were destroyed. 1800 people were killed, 300,000 houses were destroyed and hundreds of thousands were destroyed.
Facts on Cyclone Nargis
Didn’t have a dedicated monitoring centre for tropical cyclones. Warning were issued, however they were on TV and radio and did not reach poor rural communities. This meant people were killed because they didn’t know what to do and where to evacuate. 38,000 of mangrove forest was destroyed and they protect the coast from flooding. Flooding caused erosion. More than 140,000 people were killed and 450,000 houses were destroyed
