Paper 1 Hazardous Earth Flashcards
How do pressure differences regulate the Earths temperature
Land heats up quickly in summer due to darker surfaces but cools quickly in winter. When land heats, the air above it heats, expands, becomes lighter and rises forming areas of low pressure land in summer
When the Sea is heated, some sunlight is reflected and some is absorbed to 30m depth. Takes longer to heat up/cool down. In summer air over the sea is coller and denser so forms areas of high pressure
air moves from high to low pressure in a circular way
How do ocean currents regulate the Earths temperature
Cold salty water is heavy and sinks while hot salty water rises above it, creating a convection current that brings warm water from areas near the equator like the gulf of Mexico to northern areas like Europe with the gulf stream, warming up the air
What causes the ITCZ
As the earths axis tilts, the area that receives the most sunlight varies between the tropic of cancer in June and the tropic of Capricorn in December. With this brings a belt of low pressure and rain that moves between the tropics seasonally.
What were the 4 causes of climate change in the past
Asteroid collisions - Throws ash and dust into the air which blocks out the sun, just like the asteroid that caused an ice age and killed the dinosaurs
Volcanic eruptions - Throws up ash and Sulphur dioxide gas into the stratosphere which blocks out sunlight. Usually not common but in 1815, the eruption of Tambora was so large that 1816 was called the year without summer and 200,000 people died from failed harvests.
Sunspot theory - Black spots on the sun. More sunspots show higher solar activity and that more sunlight is being fired at Earth, heating it up. They can explain most previous warm and cold periods.
Orbital changes - The Earth’s orbit changes from an elliptical to a circular orbit over a long period. The Earth’s axis also tilts and wobbles. These changes affect how much sunlight the Earth receives and where it falls.
How do we know about climate change in the past
Ice cores - Every winter, a layer of snow falls in Antarctica. Air from that year is trapped in the ice which can then be taken out in the present to analyse the quantity of CO2 in the atmosphere at the time, and therefore show the climate of millions of years ago.
Tree rings - In temperate deciduous forests, trees grow every year. This can be seen from the tree rings. Larger distance between tree rings shows a more growth and therefore more CO2 and a warmer climate. While trees only survive 100 years, fossils in peat bogs can show trees from hundreds of years ago.
Past records - While they are not always accurate as they weren’t intended to record climate, consistent records of harvests/seasons, old photos, and paintings of landscapes, and written records can help to give an idea of the climate.
Explain the greenhouse effect
Greenhouse gases such as carbon dioxide and methane in the atmosphere allow short wave radiation from the sun to pass through. These rays are then reflected off the Earth but are reflected back to the Earth by the greenhouse gases. This warms up Earth significantly and makes it habitable.
Why are there big differences in CO2 production
How has pollution led to enhanced greenhouse effect
Burning fossil fuels releases greenhouse gases. This enhances the greenhouse effect as more greenhouse gases mean that more sunlight is reflected at the Earth, warming it up.
What is a tropical cyclone
A spinning storm with a wind speed of over 112km/h.
What hazards do tropical cyclones bring
Avalanches -
Storm surges - Can cause flooding
Strong winds - blow away garden furniture, knock down trees and knocks down buildings
High rainfall -
Where do tropical cyclones develop
Tropical cyclones develop in warm still ocean over 26.5℃ in late summer
Strong winds in the troposphere 10-12km over the Earth
They also need a strong Coriolis effect so does not occur at the equator as the Coriolis effect is too weak
They form between 5-30 degrees latitude
How do tropical cyclones form
1, Hot air rises and is then replaced by more air which is drawn in and up
2, This brings water vapour up which condenses to form cumulonimbus clouds and releases heat energy
3, The Coriolis effect causes rising air to spiral a round the centre. Some of it descends to form the eye of the storm
4, The storm becomes bigger as it is fed heat and moisture from the warm ocean
5, When it travels over land, it loses energy so the wind speed drops, air pressure rises, rainfall decreases and temperatures fall.
What happened in Hurricane Katrina
Social impacts of Hurricane Katrina
3000 dead
3 million without electricity
1 million refugees distributed across USA
Economic Impacts of Hurricane Katrina
$300 billion damages
30 oil plants damaged
Decrease in tourism
Environmental impacts of Hurricane Katrina
1.3 million acres of forest destroyed
Coastal habitat destroyed
Oil spills from 44 locations
Political impacts of hurricane Katrina
Racial tensions exposed as many left behind were black
Government criticised for slow response and budget cuts to coastal defence causing increased loss of life
Responses to Hurricane Katrina
Coast guard rescued 335000 out of 600,000 stranded people
$62.3 billion donated for victims
All states sent emergency equipment
