Hazardous Earth Flashcards
What two ways is heat redistributed globally?
Pressure difference (low and high pressure) and ocean currents (hot and cold water moving in different ways)
What causes pressure differences?
Heat creates zones of low pressure on land mostly ( land is easier to heat and quicker to cool so it makes the air is hotter and rises) and the sea creates zones of high pressure (absorbs a lot of heat and dose not give a lot of it off )
Which ocean current affects the UK’s climate and how?
The Gulf Stream begins in Mexico, blowing northeast where it branches towards Europe to become North Atlantic drift. It goes toward the UK creating an area of high pressure, unlike what it should be
What is the ITCZ?
A band of clouds, rain and occasional thunderstorms (low pressure). Follows the Sun to move around and causes wet and dry seasons.
What is in a high pressure zone and how is it caused?
The cold air sinks creating: No clouds Clear skies Heatwaves in summer Crisp clear frosty days in winter
What is in a low pressure zone and how is it caused?
The sun heats the ground, the warm air rises that contains water vapour and forms clouds. Then, the water vapor condenses to form precipitation
What is the global circulation model?
A theory that explains how the atmosphere operates in a series of 3 cells each side of the equator
Why is it hotter at the equator?
The Sun shines vertically there so the solar radiation is more concentrated in a smaller area resulting in it becoming hot rapidly.
What is the Hadley cell?
30 degrees either side of the equator. Low pressure at the equator but high pressure at 30 degrees
What is the Ferrel cell?
Between 30 and 60 degrees (only cell not caused by temperature)
What is the Polar cell?
Between 60 and 90 degrees. High pressure at 90 degrees and low pressure at 60 degrees
What were the past causes of global cooling?
Asteroid collisions- millions of tonnes of ash and dust enter the atmosphere and block sunlight for 5-10 years
Eruption theory- a large and explosive reaction gives off ash and sulphur dioxide; blocking sunlight for a short period
Orbital theory- oval shaped orbit causes cooling for a period as we are further away from the Sun (not as much as the other two)
What were the past causes of global warming?
Sunspot theory- sunspots are points on the Sun that are emitting more energy, so the more spots, the hotter the Earth for a long period
Orbital theory- at a point in elliptical orbit, we are closer to the Sun, causing and increase in heat
What is weather?
Daily changes in temperature, sunshine, wind direction etc
What is climate?
The pattern of weather over a longer period of time (usually 30 years)
What evidence is there for past climate change?
Ice cores- layers of ice that trap air containing CO2 for the year the ice was formed from snow
Tree rings- the thicker the ring for that year, the more CO2
Historical sources- paintings, diaries and records but these are often unreliable
Physical features- U shaped valleys etc
What gasses make up the air without human interference?
Nitrogen- 78.1%, carbon dioxide- 0.03%, oxygen- 20.9% and water vapour- 1%
What are the 4 main greenhouse gasses and their sources?
CO2- 89% and is found in fossil fuels, deforestation, factory fumes and wats
Methane- 7% and is found in rice farming, gas pipe leaks, cattle farmers and geysers
Nitrous oxide- 3% and is found in fumes from transport and fertiliser from agriculture
Halocarbons- 1% and is found in hair spray cans, deodorant cans and cleaning products
What is the human enhanced greenhouse effect?
The impact on the climate due to human activity creating increased amounts of greenhouse gasses, therefore creating additional heat
What evidence is there for current global warming?
Fossil fuels emitting greenhouse gases, CO2 and Methan at their highest levels, arctic sea ice shrinking by 10% and over 90% of the world’s valley glaciers are melting/shrinking
What future predictions are there for the climate?
More frequent extreme weather like floods, droughts and heat waves
Europe will experience less tourism due to winter snow
Crop yields will increase in countries further away from the equator
Traditional way of life will be losses as sea ice melts and temperatures increase in arctic regions
Huge loss of biodiversity
Coastal areas being lost or flooding often and areas becoming too hot inhabit
What are cyclones?
A rotating system of clouds and storms that from and develop over tropical and subtropical waters
Why are predictions for global temperatures uncertain?
Uncertain population growth, lack of knowledge about natural processes that occur which effect climate and the willingness for people to switch to more renewable energy sources
What happens in a hurricane/cyclone/typhoon
Intense rainfall- not usual for 1000mm of rain to fall in a single storm
Strong winds- whip up objects / vehicles or even take down a whole building
Storm surges- flooding usually caused by unusually high tides (created because there is less air on top of the water)
Landslides- movements of rock, debris and earth downhill, typically when the ground is saturated by rain causing it to slump
What three conditions are required for cyclones to form?
A large, warm still ocean- surface temperature needs to exceed 26.5 over a long period of time. Strong winds (118km/h) in the troposphere, 10-12km above the Earth’s surface (needed to draw up warm air rapidly from the ocean’s surface) A strong force caused by the Earth’s rotation known as the Coriolis effect (can only form 5-30 degrees either side of the equator)
When and why do cyclones decay?
On land due to lack of warm water sources.
What are the 5 stages of a cyclone formation?
Warm air currents rise from the ocean
Up currents of air hold large volumes of water which condenses to form clouds
Coriolis effect causes the rising current of air to spiral, making it cool, and descend to form the eye of the cyclone
As the cyclone moves away from the ocean, it’s fed with more heat and moisture, making it grow
It then reaches land where it losses a lot of energy, air pressure rises as temperature falls, winds drop, rainfall decreases and decays to a mere storm
Where was Hurricane Katrina?
Formed in the Atlantic
Went from a 2 to a 5 due to the Gulf of Mexico feeding it more hot water
Went through Florida as a 2 but met the Gulf of Mexico, became a 5 and then going through New Orleans, it was a 4
What key facts are there for Hurricane Katrina?
24th - 30th August 2005
80% of New Orleans flooded due to levees breaking
90000 miles squared affected
It hit land at 6 am so people were unprepared
Levees broke in 20 places
What were the social impacts of Hurricane Katrina?
1 million people displaced
1836 people died
300000 homes were destroyed
3 million left with no electricity
What were the economic impacts of Hurricane Katrina?
$110 billion worth of damage $300 billion worth of damages including secondary damages Oil platforms destroyed Shops looted Tourism decreased Fuel price increased
What were the environmental impacts of Hurricane Katrina?
Storm surges flooded large areas of the coast
Sugar cane and cotton plants were destroyed
Delicate coastal habitats were destroyed
What were the responses to Hurricane Katrina?
Awareness of hurricanes has increased Building requirements are stricter Defences like levees were improved to withstand higher categories of hurricanes $50 billion given as aid by government National Guard mobilised
What is a primary effect?
Things that happen instantly
What is a secondary effect?
Things that happen in hours, days and weeks after the initial hazard
