Global Temperatures, weather, climate change Flashcards
In an area of land where it’s mainly forest, what will the pressure be and why?
Low pressure because dark surfaces absorb sunlight which is converted to heat so the land heats up quickly in the summer causing air to rise
What kind of pressure forms over the sea and why?
High pressure because it takes more time to absorb heat as it’s a light surface and so air remains cooler and denser causing it to sink
What is the albedo effect?
Where light surfaces reflect more solar radiation and dark surfaces absorb more solar radiation
Why is the North Pole colder than Africa?
As it’s further from the equator and so the solar radiation has to hit it at an oblique angle and has to travel further so it’s less concentrated
What is climate?
The average temperature and precipitation over a long period of time.
What is the Gulf Stream?
Warm ocean currents driven by westerly winds
Describe where the Gulf Stream begins and its movements.
It begins in the Gulf of Mexico blowing north east where a branch heads towards Europe and then becomes the North Atlantic drift
What keeps sea temperatures in January at a reasonably warm 11°?
The North Atlantic drift
What happens to the North Atlantic drift once it reaches Greenland and northern Canada?
It cools and turns south forming Labrador currents
Describe the formation of the currents in the ocean in terms of convection currents starting with the North Atlantic
- North Atlantic water is cold, heavy and quite salty so it sinks
- This sets up convection currents which drags surface water down
- The convection current draws warmer salty water I bet the ocean surface from areas near the equator such as the Gulf of Mexico
- This then cools and sinks in the Labrador and Greenland seas and then flows south towards the equator where it’s warmed again
Why are their icebergs near Newfoundland?
Due to cold Labrador currents moving towards the Gulf of Mexico
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 does the atmosphere mean the equator is warmer than the poles?
Because the atmosphere contains particles that absorb heat and at the equator, solar radiation passes through the atmosphere at a direct angle so less heat is lost
State the cells in order of the earth.
Polar cell Ferrel cell Hadley cell Hadley cell Ferrel cell Polar cell
What does air do at the Hadley cell and what’s its effect?
The air at the Hadley cell is warm and rises towards the poles where it then sinks causing high pressure
Describe the movement of air based on the global circulation model
Cold air at the poles moves towards the equator and warms up causing it to rise again
Describe the Hadley cell, thermally direct or indirect?
- The Hadley cell is where warm air travels to around 30° north where it cools and sinks to the surface before returning to the tropics. This creates an area of Hugh pressure
- the cell is thermally direct
Describe the polar cell, thermally direct or indirect?
It’s much smaller than the Hadley cells and is where cold air sinks at the North Pole and then flows south at the surface. At around 60° north, the air is warmed by contact with the land or ocean here and begins to rise
Thermally direct
Describe the ferrel cell, thermally direct or indirect?
It’s found between the Hadley and polar cells that lie between 30° and 60° north
It’s thermally indirect as it’s powered by two other cells
What’s the atmospheric cell over the uk?
The ferrel cell
What cell is responsible for bringing the uk cold and wet weather?
The polar cell as the cold air from here sinks down moving towards the equator
Which cell is the largest?
Hadley cell
Describe low pressure
Forms wet weather where there are storms. This is because warm air rises and cools allowing water vapour to condense and form precipitation
Describe high presssure
Here, air is heated at the equator where pressure is low, it then rises and begins to descend at 30° latitude once the air has cooled. As cool air descends, it warms so clouds don’t form as air isn’t going up to condensate
At the surface of our atmosphere, air flows from belts of…
High pressure to belts of low pressure
At the higher atmosphere, air flows from belts of…
Low pressure to high pressure
What is the inter tropical convergent zone?
The ICTZ is a zone of convergence attempts thermal equator where the trade winds meet. It has a belt of low pressure and migrates with the changing position of the thermal equator
Describe the effect the ICTZ has on a specific climate
It affects Africa’s climate by making it very varied as it runs straight through it
State the pressure belts in order from the top of the earth to the bottom
Polar high Subtropical low Subtropical high Equatorial low Subtropical high Subtropical low Polar high
What do you need to construct a climate graph?
A title Rainfall in mm on the y axis Months of the year on the x axis Temperature in ° on another y axis Bars represent the rain The line graph represent the temperature
What are the causes of climate change before humans existed
Volcanoes
Asteroid impacts
Changes in the earths cycle every thousand - hundred thousand years
What are the theories for the causes of past climate change called?
The eruption theory
Asteroid collision
The sunspot theory
The orbital theory
Explain the eruption theory
The idea that a large eruption will produce a lot of ash and CO2 which if risen high enough could spread around the stratosphere and preventing sunlight reaching the earths surface as it would get reflected by the ash.
Explain the asteroid collision theory. How long will it have lasted?
The idea that every 500,000 years, a km sized asteroid strikes and so in the past, a strike from this would cause millions of tonnes of ash and dust to spread into the atmosphere and block out sunlight similar to volcanoes. It’s effect would have lasted 5-10 yrs
Explain the sunspot theory
Where did it originate?
What do they tell us?
How could tent have caused climate change?
- Over 2000 yrs ago, Chinese astronomers recorded sunspots. Sometimes they are present and other times they disappear
- they tell us the sun is more active than usual so many spots means more energy is being fired out from the sun towards the earth
- changes in sunspot activity could have caused the little ice age or the medieval warmer period
Explain the different sections of the orbital theory and how it could have changed the earths climate
- The earths orbit is sometimes circular and sometimes more of an ellipsis
- The earth’s axis tilts so it’s sometimes more upright and sometimes more to the side
- The earth’s axis wobbles like a spinning top
These all alter the amount of sunlight the earth would have received so over time scales of thousands of years, the change would be enough to start an ice age or end one
What are the main pieces of evidence that tell us about past climates?
Ice cores, tree rings and historical sources
For ice cores,
What are they?
How do they tell us about past climates?
What are their limitations?
- They are ice sheets that contain layers of ice
- they show past climates as each layer is formed from a year of snowfall. The air bubbles trapped in older layers of ice preserve air and CO2 from when the snow fell and so the ice is drilled into to measure the amount of CO2
- they are limited as they can be contaminated and do not present the whole world
For tree rings,
What are they?
How do they tell us about past climates?
What are their limitations?
- They are the rings inside the bark of trees.
- Trees grow in temperate climates each year in the summer so the larger the growth, the bigger the ring suggesting more heat. This shows past climate as the growth can be seen from no of rings in the tree
- they are limited because the rings can’t go back very far due to trees having a short lifespan if 100yrs
For historical sources,
What are they?
How do they tell us about past climates?
What are their limitations?
- They are photos, paintings, diaries or newspapers from the past that can give us an insight to the climate
- they are useful as we can analyse the image and what it suggests and looking at recorded dates or regular events like a harvest
- they are limited as they were not usually intended to show climate and some could be bias
What are the gases that make up the atmosphere and give their percentages
Nitrogen (78.8%)
Carbon dioxide (0.03%)
Oxygen (20.9%)
Water vapour (1%)
What is the greenhouse effect?
The way gases in the atmosphere trap heat from the sun and they prevent a large amount of solar radiation from escaping causing the earth to be at a comfortable temperature
For carbon dioxide,
What % of it do we produce?
Where does it come from?
What’s its % increase since 1850?
- 89%
- burning fossil fuels and deforestation
- +30%
For methane,
What % of it do we produce?
Where does it come from?
What’s its % increase since 1850?
- 7%
- gas pipeline leaks, farming rice in paddy fields, cattle farming
- +250%
For nitrous oxide,
What % of it do we produce?
Where does it come from?
What’s its % increase since 1850?
- 3%
- jet aircraft engines, cars, lorries, fertilisers And sewage farms
- +16%
For halocarbons,
What % of it do we produce?
Where does it come from?
- 1%
- Industry (factories), solvents and cooling equipment
What do we have to take into account when predicting future climate?
Population, governments and use of renewable resources
What are the evidence for global warming?
- 1998 was the warmest year in history followed by 2005 and 2010
- the arctic sea has declined by 10% in the last 30yrs
- sea levels rose by 210mm between 1870 and 2010
- over 90% of the worlds valley glaciers are shrinking
Give 3 future predictions for the earth due to climate change
- crop yields could increase in east and Southeast Asia
- erosion of beaches and bleaching of coral reefs in the Pacific islands
- in Southern Europe, there will be increased pressure on water sources
Why may people in developing countries produce small amounts of greenhouse gases?
- As they don’t have the money to afford industries that may produce a large amount of greenhouse gases
- people in general may not have enough money to afford cars so lower greenhouse gas emission
Name 4 greenhouse gases that humans are producing which are making global warming worse
Carbon dioxide
Methane
Nitrous oxide
Halocarbons
What is the trend with countries emitting the most greenhouse gases?
MEDCs emit the highest number and so do highly populated countries so an MEDC with a high population will emit a lot of greenhouse gases
What country emits the most greenhouse gases in the world and state how much
North America with 14.5 tonnes of CO2 emitted per person in 2012
Why is it hard to predict climate change?
It relies on numerous factors and the world is constantly changing
What is the enhanced greenhouse effect?
The impact on the climate from additional heat being retained due to increased amounts of carbon dioxide and greenhouse gases that humans have released into the atmosphere
Give a positive future predictions of climate change
-crop yields in east and Southeast Asia could increase
Give 4 negative future predictions on climate change
- there could be loss of tourism in Europe due to winter snow
- in Southern Europe there will be increased pressure on water sources
- there will be climate refugees as people from low lying places are evacuated
- there will be erosion of beaches and coral reefs in the Pacific islands
