5th Form Geography Revision
Notes:
- All case studies are at the bottom
- Blue = fact
- Orange = definition
Changing Climate
https://quizlet.com/gb/758912232/geography-climate-change-flash-cards/
Quaternary Period
- The current period has covered 2.6 million years.
- Characterised by Ice Ages (or glacials) which have 100,000 year cycles
- We are currently in a brief period of warmth called an interglacial
- Last Ice age peak was 18,000 years ago
- Holocene epoch (current, started 11,000 years ago), Pleistocene epoch (2.5 million
to 11,000 years ago)
- Ice sheets expanded - erosion and deposition everywhere
Evidence for climate change
- Positive correlation between CO2 levels and temperature
- Best way is to combine many different sources of proxy data
- Proxy data is an estimate of past and a substitute for directly measurable data
Ice cores
- Most reliable
- Go back 800,000 years
- Very well preserved
Geological Cores
- Less reliable
- Finds oxygen isotope levels instead (found in sedimentary buildup)
- Indicator of temperature by comparing concentrations
- Dates from 2,000,000 - 500,000,000 years
Biological data (e.g. tree rings)
- Can only go back ~2000 years
- Tree rings grow further part in good years, tighter in worse years
- More accurate and localised than ice cores
Historical accounts (they are rubbish)
- Don’t date back far
- Not accurate
,Causes of Climate Change
Solar output
- Occur in 11 year cycles
Volcanic activity
- Produce greenhouse gases - however in past 10 years only 1% of emissions were
from volcanoes
Changes in Orbit (Malenkovitch cycles)
Following combined can cause 1-2˚C change in temperature (called Milankovitch cycles)
- Eccentricity
- Stretching of orbit creating elliptical orbit
- Cycle takes 100,000 years
- Perihelion = closest point to sun, Aphelion = farthest point from sun
- Obliquity
- Tilt of earth’s axis
- Cycle takes 400,000 years
- Precession
- Wobble of the planet
- Cycle takes 20,000 years
Greenhouse effect
- Occurs when short-wave UV radiation is absorbed by GH gases and remits back to
earth as weaker long-wave infrared radiation, causing more heat.
- All warming since 1950 is due to human action
- Planet has warmed 1-1.2˚C since 1950
- Sea ice has decreased 12% per decade since 1979
Impacts of climate change
Flooding
- Land ice melting causing sea level rise
- Countries such as Netherlands will be underwater
- Over 600 million will be directly affected
Poor Harvests
- Due to more droughts/floods/extreme weather
Polar regions
- Melting of sea ice, destroy ecosystems and habitats
- Pro: May open new trading routes
Extreme weather
- Will increase in frequency, intensity, and duration
- In 2003, 650,000 ha of Portugal’s forest was burnt, caused 1 billion euro damage
Ocean Acidification
- Due to CO2 dissolving making carbonic acid
, - Bleaches and kills coral
Impacts on UK
Higher Temperatures
- More heatwaves
- 2000 heat related deaths per year
- Pro: more agricultural production and vineyards
Rainfall change
- Water demand exceed supply
- 15% of agricultural is classified as poor
Sea level change
- Annual flood damages of £1.1 bn
- Need flood defences which are expensive
UK in the 21st century
Types of Rainfall
Relief rainfall
1. Warm, moist air from the ocean rises up over mountains.
2. As it rises, it cools and condenses to form clouds, which brings rain.
3. Once the air has passed over the mountains, it descends and warms.
4. This creates drier conditions known as a rain shadow.
Convectional rainfall (usually in UK summers)
1. Sun heats the land
2. Warm air rises rapidly
3. It cools and condenses to form clouds, which brings rain.
4. These clouds can be large cumulonimbus clouds which produce heavy rainfall and
thunderstorms.
Frontal rainfall
1. Warm front meets a cold front
2. Heavier cold air sinks to the ground and the warm air rises above it.
3. As it rises, it cools and condenses to form clouds, which brings rain.
Air masses
Large parcels of air with the same climate characteristics of temperature and humidity
Water supply definitions
Water deficit - demand of water > supply
Water surplus - supply of water > demand
Water stress - pressure on water supplies caused by demand exceeding or threatening to
exceed supply
, Housing shortages
● 3.6 million people are living in an overcrowded home
● 2.5 million are unable to afford their rent or mortgage
● 2.5 million are in "hidden households" they cannot afford to move out of, including
house shares, adults living with their parents, or people living with an ex-partner
● 1.7 million are in unsuitable housing such as older people stuck in homes they
cannot get around and families in properties which have no outside space
● 1.4 million are in poor quality homes
● 400,000 are homeless or at risk of homelessness
Reasons for Housing Shortages
- NIMBY-ism – Not In My BackYard. Many people oppose new housing being built near
their homes.
- Rising demand for second homes - particularly from wealthy businessmen overseas
- 30% increase in number of households since 1971 - due to more people living alone
- 70% of new homes are wanted by single people
- UK population has increased by 16% since 1971 and is continuing to rise
- Government investment and involvement in house building has fallen - 168,000
local-authority homes were built in 1951, only 1320 were built in 2010.
- The Greenbelt - legislation that prevents developers building on open spaces -
especially in major cities such as London
Demographic Transition Model
The DTM shows how birth rate and death rate affect the total population of a country
Ageing Population
- Improved healthcare, new treatment for diseases such as cancer or heart conditions,
thus prolonging life
- Greater awareness of the benefits of a good diet, less smoking, drinking, etc.
Notes:
- All case studies are at the bottom
- Blue = fact
- Orange = definition
Changing Climate
https://quizlet.com/gb/758912232/geography-climate-change-flash-cards/
Quaternary Period
- The current period has covered 2.6 million years.
- Characterised by Ice Ages (or glacials) which have 100,000 year cycles
- We are currently in a brief period of warmth called an interglacial
- Last Ice age peak was 18,000 years ago
- Holocene epoch (current, started 11,000 years ago), Pleistocene epoch (2.5 million
to 11,000 years ago)
- Ice sheets expanded - erosion and deposition everywhere
Evidence for climate change
- Positive correlation between CO2 levels and temperature
- Best way is to combine many different sources of proxy data
- Proxy data is an estimate of past and a substitute for directly measurable data
Ice cores
- Most reliable
- Go back 800,000 years
- Very well preserved
Geological Cores
- Less reliable
- Finds oxygen isotope levels instead (found in sedimentary buildup)
- Indicator of temperature by comparing concentrations
- Dates from 2,000,000 - 500,000,000 years
Biological data (e.g. tree rings)
- Can only go back ~2000 years
- Tree rings grow further part in good years, tighter in worse years
- More accurate and localised than ice cores
Historical accounts (they are rubbish)
- Don’t date back far
- Not accurate
,Causes of Climate Change
Solar output
- Occur in 11 year cycles
Volcanic activity
- Produce greenhouse gases - however in past 10 years only 1% of emissions were
from volcanoes
Changes in Orbit (Malenkovitch cycles)
Following combined can cause 1-2˚C change in temperature (called Milankovitch cycles)
- Eccentricity
- Stretching of orbit creating elliptical orbit
- Cycle takes 100,000 years
- Perihelion = closest point to sun, Aphelion = farthest point from sun
- Obliquity
- Tilt of earth’s axis
- Cycle takes 400,000 years
- Precession
- Wobble of the planet
- Cycle takes 20,000 years
Greenhouse effect
- Occurs when short-wave UV radiation is absorbed by GH gases and remits back to
earth as weaker long-wave infrared radiation, causing more heat.
- All warming since 1950 is due to human action
- Planet has warmed 1-1.2˚C since 1950
- Sea ice has decreased 12% per decade since 1979
Impacts of climate change
Flooding
- Land ice melting causing sea level rise
- Countries such as Netherlands will be underwater
- Over 600 million will be directly affected
Poor Harvests
- Due to more droughts/floods/extreme weather
Polar regions
- Melting of sea ice, destroy ecosystems and habitats
- Pro: May open new trading routes
Extreme weather
- Will increase in frequency, intensity, and duration
- In 2003, 650,000 ha of Portugal’s forest was burnt, caused 1 billion euro damage
Ocean Acidification
- Due to CO2 dissolving making carbonic acid
, - Bleaches and kills coral
Impacts on UK
Higher Temperatures
- More heatwaves
- 2000 heat related deaths per year
- Pro: more agricultural production and vineyards
Rainfall change
- Water demand exceed supply
- 15% of agricultural is classified as poor
Sea level change
- Annual flood damages of £1.1 bn
- Need flood defences which are expensive
UK in the 21st century
Types of Rainfall
Relief rainfall
1. Warm, moist air from the ocean rises up over mountains.
2. As it rises, it cools and condenses to form clouds, which brings rain.
3. Once the air has passed over the mountains, it descends and warms.
4. This creates drier conditions known as a rain shadow.
Convectional rainfall (usually in UK summers)
1. Sun heats the land
2. Warm air rises rapidly
3. It cools and condenses to form clouds, which brings rain.
4. These clouds can be large cumulonimbus clouds which produce heavy rainfall and
thunderstorms.
Frontal rainfall
1. Warm front meets a cold front
2. Heavier cold air sinks to the ground and the warm air rises above it.
3. As it rises, it cools and condenses to form clouds, which brings rain.
Air masses
Large parcels of air with the same climate characteristics of temperature and humidity
Water supply definitions
Water deficit - demand of water > supply
Water surplus - supply of water > demand
Water stress - pressure on water supplies caused by demand exceeding or threatening to
exceed supply
, Housing shortages
● 3.6 million people are living in an overcrowded home
● 2.5 million are unable to afford their rent or mortgage
● 2.5 million are in "hidden households" they cannot afford to move out of, including
house shares, adults living with their parents, or people living with an ex-partner
● 1.7 million are in unsuitable housing such as older people stuck in homes they
cannot get around and families in properties which have no outside space
● 1.4 million are in poor quality homes
● 400,000 are homeless or at risk of homelessness
Reasons for Housing Shortages
- NIMBY-ism – Not In My BackYard. Many people oppose new housing being built near
their homes.
- Rising demand for second homes - particularly from wealthy businessmen overseas
- 30% increase in number of households since 1971 - due to more people living alone
- 70% of new homes are wanted by single people
- UK population has increased by 16% since 1971 and is continuing to rise
- Government investment and involvement in house building has fallen - 168,000
local-authority homes were built in 1951, only 1320 were built in 2010.
- The Greenbelt - legislation that prevents developers building on open spaces -
especially in major cities such as London
Demographic Transition Model
The DTM shows how birth rate and death rate affect the total population of a country
Ageing Population
- Improved healthcare, new treatment for diseases such as cancer or heart conditions,
thus prolonging life
- Greater awareness of the benefits of a good diet, less smoking, drinking, etc.
