Chapter 2 - Climate and change

Natural changes in climate
1. The last cold period (Pleistocene) started 2.6million years ago and ended 10,000 - glacial ice age
  1. The most recent 10,000 years has been warmer - interglacial (Holocene)
    1. both are referred to as the 'quaternary Period'
  2. Evidence
    1. ice cores 3km deep - 500,000 years old
      1. melting releasing bubbles - analyses change in air content showing how temps. have warmed/ cooled
    2. fossil record
      1. animals preferring warm/coolconditions that were alive
Natural causes of climate change
1. orbital change
  1. ever 100,000 years the earth's orbit changes from circular to elliptical
    1. This changes how much sunlight earth recieves
2. Axis
  1. earth;s axis moves + wobbles chnging in 41,000 and 21,000 year cycles
    1. affecting sunlight recieved
3. solar output
  1. sunspot theory - uneven temp. develop on sun's surface
    1. changes the amount of solar energy emitted - more spots = more energy
  2. 11 year cycles
4. Volcanic activity
  1. eruptions pump dust and ash into atmosphere, blanketing the Earth causing a cooling effect
    1. Pinatubo 1991 - sulight reduced by 10% - temps. fell 0.5 for a year
5. Asteroid collisions
  1. Cause cooling - dust cloud blocks out sun
    1. extinction of dinosaur 65 million years ago
    2. huge fires - co2 - warming?
The little ice age and medieval warm period
1. evidence
  1. diaries, folklore, paintings, books, newspapers
    1. tree rings in old trees are thinner for cold years
      1. coral grows slower when cold
2. warm period
  1. vikings sailed north
    1. settled and farmed in greenland
      1. less arctic ice
3. little ice age
  1. A colder period in northern europe from 15th-17th century
  2. crops did not grow well - less productivity and food
  3. winters were very cold, summers short
    1. 'ice fairs' on river thames between 1907 and 1814
4. causes
  1. fewer sunspots and volcanic ash in atmosphere (not humans)
extinction
1. megafauna (KILLED BY HEAT)
  1. Mammoths, giant beavers and sabre-toothed tigers evolved during ice age
    1. ice age ended temp. rose by 5 degrees in 10,000 years
      1. couldn't adapt to warmer climate + became extinct
        hunting by humans could have been a contributing factor
      2. retreated north
  2. 10,000 - 15,000 years ago
2. Dinosaurs (KILLED BY COLD)
  1. 65 million years ago
    1. asteroid - dust blocked out sun
      1. volcanic activity?
        ecosystem collapse - plant life change - food chains
UK Climate
1. Has a cool, 'temperate maritime' climate
  1. Gulf stream keeps west coast warmer than would be expected
    1. prevailing winds from Atlantic ocean in south west - pick up moisture from sea + bring rain
  2. precipitation 700mm to 2500mm
    1. rainfall high on west coast - recieves frontal rainfall brought by Atlantic depressions
  3. air masses - scandinavia (cold) + north africa (warm)
human causes
1. Carbon dioxide + methane are greenhouse gases linked to human activity
  1. the rise in emissions matches the start of industrial revolution
    1. CO2 highest in 650,000 years
      1. CH4 highest in 900,000 years
        Methane is 21 times more potent
2. How are they produced?
  1. carbon dioxide
    1. industry e.g steel + cement making
      1. energy - burning fossil fuels
        transport increase so oil burnt for petrol and diesel
        deforestation releases carbon store
  2. Methane
    1. raising of livestock
      1. wind given off by cattle - 10% of autralia's carbon footprint
    2. Production + transport of coal, oil, gas
      1. decomposition of organic waste
  3. Nitrous Oxide
    1. emitted during agricultural and industrial activities
      1. combustion of solid waste an fossil fuels
The Greenhouse Effect
1. 1. The sun warms the Earth's surface
  1. 2. most of the sunlight is absorbed by the earth and warms it
    1. 3. some heat energy radiates back into space (infrared waves)
      1. 4. Some of the outgoing heat is trapped by greenhouse gases, warming atmosphere
2. without it it would be 30 degrees cooler- too cold for humans
  1. however human activity causes an 'enhanced greenhouse effect'
IPCC believe that 550 parts per million CO2 conc. is a 'tipping point'
1. Below 550ppm
  1. temp. rise will not go beyond 2 degrees
    1. sea level rise from melting glacial ice - up to 1m (coastal flooding)
      1. more storms + hurricanes due to warmer sea temp.
        some species may become extinct or migrate
        warmer conditions may encourage growth and biodiversity at high latitudes
2. Above 550ppm
  1. global temp. rise of 6 degrees or more
    1. ice cap melt - loss of bright white surface to refect sunlight back to space - more energy absorbed by Earth - greater temp. rise
      1. Billions will lose their homes (sea level rise)
        change in world weather patterns - droughts/ storms lead to famine and disasters
        animal + plant species wouldn't be able to adapt
        ice free?
        loss of fresh water supplies
Economic/ Environmental Impacts of climate change of the UK
1. Developed countires being able to deal with climate change
  1. Holland: built enormous embankments to protect low-lying areas it has recaimed from the sea
    1. London: Thames barrier protects from high sea levels that drive North sea water inland into the estuary
2. Environmental
  1. Sea level rise - loss of coastal land + increased erosion - low-lying cities flooding e.g. London
    1. severe storms + longer summer droughts
  2. change for fishing industries if species migrate
    1. Ecosystem change, species move to new areas, new invasive species emerge
      1. warmer temp. encourage disease e.g malaria
      2. e.g black grouse disappearing form Highlands
3. Economic
  1. Growing seasons will be different in Scotland - new crops - improving agriculture
    1. cost of climate change refugees - migrated from poorer countries
  2. Hotter summers - boost tourism
    1. less oversea travel?
  3. London flooding - damage would be extremely expensive + disruptive
  4. cost of protecting places from flooding- some cases not practical
    1. Housing design - altered so less water is wasted
  5. AC units - more electricity
Climate change in developing countires
1. Maldives
  1. less than 2 metres above sea level
    1. 400,000 could become climate change refugees
  2. Tuvalu
    1. 5,000 residents of the Pacific island live only 3m above sea level
2. Bangladesh
  1. low-lying country - very large (160 million people) and poor population - extremely vulnerable
    1. much land near sea level on the Delta of river Ganges - land is naturally sinkinging + subsiding
  2. Environmental
    1. River flooding (already severe) - become worse from increased rainfall and sea level rise
    2. Tropical storms - more frequent - further inland - more damage
      1. longer drier season - droughts
  3. Ecomomic
    1. small sea level rise - massively reduce farmland + agricultural output
    2. more river flooding - more damage to homes - diruption to lives + economy
      1. more intense tropical storms spreading inland - home, live, infrastructure damage
        fast-growing population - many farmers - need land to work
    3. cost of protecting homes and businesses - more than can afford
      1. coastal flooding damage crops - too salty to grow
        shrimp farming is important but rising sea temp. may damage this form of aquaculture
        Flooding - spread of water-borne disease
    4. Flooding - interupted schooling due to damage
      1. if the country is to be lifted from poverty - safeguarding education is vital
        needs wee educated citizens
3. Poorer countries are more vulnerable to natural hazrds than rich counties

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