Climate Change


1.1 World's major climates & biomes

Major Climates

  • Tropical Forest                               - Mediterranean Forest                          - Temporate Forest
  • Coniferous Forest                          - Grassland                                            - Desert & Scrub
  • Tundra & Ice Desert

Biomes & Climate

  • Biomes are determined by climate, average temperature and annual precipitation- Climatic Climax Communtiy
  • There is a close resemblance between distribution of climate types and the distribution of biomes
  • Biomes: naturally surviving plant communities in a region that form large-scale zonal ecosystems
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1.2 Temporal patterns of Climate Change

Climate changes naturally through a series of cycles;

  • Long-term Cycle: Ice ages (colder climate) and Interglacial periods (warmer climate)
  • Short-term Cycle: Bronze Age (warmer climate) and Little Ice Age (colder climate) 

Causes of Short-Term Climate Change

  • Volcanic Eruptions: affect global climate for a year or two.  Large quantities of Sulphur Dioxide and dust into stratosphere causing the aerosol effect, resulting in incoming solar radiation being reflected- reducing temperatures
  • El Nino(warm surface water eastern equatorial pacific) and La Nina (colder-than-average sea-surface temperatures)

Causes of Long-Term Climate Change

  • Shifts in Earth's Orbit: Milankovitch Cycle (variation in Earth's tilt, orbit and eccentricity).  Eccentricity (changes in degree of roundness of the Earth's spherical shape)
  • change in weather patterns affect the ocean-atmosphere conveyer system, weakening the Gulf Stream or North Atlantic Drift which normally brings warm tropical ocena current to N.W. Europe
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El Nino & La Nina

El Nino Year (warm surface water in eastern equatorial pacific)

  • Trade Winds in Western Pacific weaken, die out or blow in the opposite direction
  • Water pilled up in the West moves back towards the East resulting in calmer conditions across the Pacific Ocean
  • Air circulation loop reversed so air sinks in the Western Pacific bringing drought in that region
  • Air rises in eastern Pacific causing convectional rainfall sometimes leading to floods in South America
  • Fish Numbers decrease

La Nina Year (colder-than-average sea-surface temperatures in central & eastern pacific)

  • Very strong Walker loop
  • Extremely strong trade winds, pushing warm water westwards- raising sea levels in Indonesia
  • Deep low pressure over southeast Asia, causing heavy rain due to the strong convectional uplift from warmer-than-usual seas
  • Eastern side of Pacific, strong up-welling of cold water off the coast of Peru.
  • Higher-than-average pressure- extreme drought in semi-arid areas of northern Chile & Peru
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1.3 Causes of climate Change

Evidence for Climate Change;

  • Ice Cores- drilled from ice sheets in Greenland & Antarctic
    • Able to analyse past atmospheric composition and build up detailed records of past levels of Carbon Dioxide
    • Analysis indicates a positive correlation between temperature change and CO2 concentration in the atmosphere
  • Glacial deposits- natural record of ice advance and retreat with changes in temperature
    • Moraine and glacial till material can be dated to show the extent of glaciers to reconstruct the chronology of changing temperatures
  • Drendrochronology- studying tree rings
    • Matching the rings of fossil trees with living trees, a continuous record of climate over the last 8,000 years have been made
  • Radiometric (radiocarbon) dating- measures age of certain isotopes based on rate of decay
    • able to determine the age of fossils, and the type of fossils indicates the prevailing climate.
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1.3 Causes of climate Change Continued

Atmospheric Processes

  • Greenhouse Effect: lower atmosphere is heated as the radiation emitted from the Earth's surface is absorbed by greenhouse gases, keeping average global surface temperatures higher
  • Global Warming: 'Enhanced Greenhouse Effect'- increase in concentration of greenhouse gases in the atmosphere so more solar radiation is absorbed into the atmoshere raising temperatures further. 


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1.3 Causes of climate Change Furthered

Greenhouse Gases

  • Water Vapour- increased evaporation from manmade water bodies (reservoirs) & steam emissions (power station cooling towers)
  • Carbon Dioxide (CO2)- combustion of fossil fuels and deforestation
  • Methane (CH4)- expanded livestock farming and rice production to meet needs of growing population. Leakages of methane from natural gas fields and pipelines, coalmines and landfill sites
  • Nitrogen Oxides (NOx)- motor vehicles and power stations as well as production and use of nitrate fertilisers, especially with more water-logged soils
  • Ozone- stratosphere ozone depleted due to release of CFCs- this Ozone is essential for protecting life on earth by absorbing most harmful ultraviolet radiation.
    • Ozone in the troposphere is a result of human activity. 
    • Low-level Ozone created when sunlight causes a photochemical reaction with Nitrogen Oxides and vehicle emissions
  • Chlorofluorcarbons (CFCs)- aerosol propellants, fire extinguishers etc. Being phased out- Montrel Protocol but 100 year lifespan means they continue to exist in the environment.  Found in troposhere and destroy ozone in the stratosphere
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1.3 Causes of climate Change Extended

Evidence for Global Warming

Retreating ice sheets and galciers, and rising sea levels

  • Glaciers in Mount Everest region of Himalayas are retreating rapidly
  • Attributed to rising sea tempreatures
  • Recession in outlet glaciers of Greenland and Antarctica Ice Sheets are destablishing them
  • Glaciers e.g. Helheim, drain nearly 1/5 of the Greenland ice sheet
  • Permafrost Layer Melting- Building and road damage

Extreme Weather Events

  • Heat of Oceans increase the intensity and frequency of hurricanes
  • Droughts increased in length and intensity, affecting spain, Australia and East Africa

Moving Biome Boundries

  • Spruce Trees in Yukon, Northern Canada taking over former Tundra
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1.3 Causes of climate Change Adittional

Environmental and Human Factors

  • Ruddiman Hypothesis- Ice Age is post-poned due to early farming activities leading to increasing CO2 and CH4 emissions
  • Gaia Principle- The Earth regulates itself through negative feedback. 
    • Damage to the biosphere and the increase in greenhouse gas emissions are testing the Earth's ability to self-regulate
    • increasing the change of positive feedback and therefore runaway global warming.
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1.4 Issues resulting from Climate Change

Changing climates, shifting climatic belts and the effect on biomes

  • Migration of climatic belts- impact hydrology, ecosystems and economics
    • Temperate grasslands, steppes of north Asia and North American prairies (bread baskets of the world- principle grain-growing areas), drier summers and colder winters, reducing grain production and potentially food shortages and famine.
    • Creeping desertfication in the Sahel may be stopped as the rainbelt moves North
  • Ecological impacts as climatic belts shift
    • Species must adapt or migrate to survive and so are invading new areas and mixing with formerly non-overlapping species
    • causing knock-on effects thhroughout the ecosystem sometimes causing extinctions as ecosystem structure is altered.
  • Pests and diseases, e.g. Malaria, will move beyond usual locations
    • Malaria is one of the biggest killers in tropical and subtropical climates. Children particulalry vunerable and major hinderance to economic development
  • Melting permafrost affects habitats, wildlife and people who rely on the land for their livelihood
    • causes subsidence and damage to settlements, transport & oil pipelines in Alaska & Siberia
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1.4 Issues resulting from Climate Change Continued

  • Drought- Murray-Darling Basin Australia, need several years of above average rainfall to recover.  Wetlands seriously degraded- 50%-80% severly damaged or completely destroyed.  Agricultural output reduced.
  • Heatwaves- become more frequent.  August 2003- 40,000 deaths in Western Europe.  Heatwaves are combined with extended dry periods  result in increasing forest fires- Victoria, Australia February 2009.  Heat and wind lead to Firestorms- N.E Melbourne- 120 deaths.
  • Heavy daily precipitation/Fooding- South/ South East Asia~ Thailand 2011.  Heavy rainfall in UK caused major flood events e.g Tewkesbury in 2007. 
  • Increasing occurance of El Nino- increase tropical cyclone activity around the Pacific, increasing chance of extreme weather events

Melting Glaciers, rising seal levels and the impact on people

  • retreating glaciers affects availability of fresh water for irrigation, domestic & recreation e.g skiing
  • Sea level expect to rise because of thermal expansion and melting glaciers and ice sheets on land leading to significant coastal impacts- coastal erosion, flooding & possible loss of coastal wetlands and wildlife e.g. wading birds and shallow-water fish species. 
  • Most vulnerable are low-lying and desley populated areas e.g. Bangladesh
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1.4 Issues resulting from Climate Change Furthered

Variation of impacts

  • Tropical Corals- very fragile ecosystem; sea level rise & warmer sea temperatures threaten existence, cauing bleaching & death.  Rising sea levels outstrip corals' rate of growth, submerging them below preferred depth.
  • Ocean acidification- seriously harm marine organisms e.g. Corals, Lobsters and Sea Urchins.  CO2 dissolves in sea water forming carbonic acid and fixed organisms (corals) can't survive & other species migrate.

How could UK be affected?

  • expected greater warming in south and east with more frequent hot drier summers and milder wetter winters with reduced snowfall.
  • Weather related impacts; heavier rainfall increasing pressure on drainage systems; summer droughts causing low stream flows, water shortages and risk of subsidence; heatwaves bringing health risks, especially to the elderly.
  • Cereal crops- warmer temperatures mean UK has an extended growing season. 
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1.4 Issues resulting from Climate Change Extended

Impacts on Society

Food Supply

  • climate change will affect agriculture and food production around the world because;
  • more CO2 in the atmosphere, enhancing photosynthesis
  • increased frequency of extreme events
  • spread of pests and diseases
  • Africa, Middle East & India expected reductions in central yields, and regions at higher latitudes have increased crop yeilds


  • increase malnutrition
  • increased deaths, diseases and injury due to extreme weather events

Water Resources

  • Mediterranean basin, Wrn.USA, Srn.Africa & NErn. Brazil suffer decrease in water supply
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1.4 Issues resulting from climate change Additiona

Migration and Conflict

  • Competition over natural resources becoming increasingly scarce due to climate change
  • Increased drought, water shortages and river and coastal flooding would affect many people leading to relocation within or between countries.
  • Increase migration pressures and ethnic conflicts causing political tension. 
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1.5 Strategies to address Climate Change

two main ways: Mitigation and adaption

Mitigation Strategies- reducing gas emissions and increasing sinks for these gases

  • Replecing fossil fuel consumption- obvious mitigation strategy but its probably unrealistic until coal resources approach exhaustion.  Motor vehicles continued to be fuelled with petrol or diesel
  • Renewable energy- solar power, wind turbines, tidal/wake energy and use of biofuels.  Development need considerable investment in new infrastructure
  • Energy conservation- people encouraged to buy low-energy bulbs, insulate homes properly, stop leaving appliances on standby and drive in more fuel-efficent ways.  Developers encouraged to build zero-carbon buildings- 2010 Green Deal
  • Transport policies- reduce congestion, pollution & saving energy. Congestion charging, light railway and tram schemas, increasing car park charges & encouraging cycling & walking
  • Forestry- increasing carbon sink byy limiting deforestation & extending the conversation of existing forests
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1.5 Strategies to address Climate Change Continued

Adaptation Strategies- changing lifestyles

International Level

  • Kyoto Protocol- (international agreement signed in Japan Decemebr 1997) aim to reduce greenhouse gases and became law February 2005.  USA's target not binding as so far declined to fatify the agreement
  • Intergovernmental Panel on Climate Change (IPCC)- provide a well-researched scientific view on the current state of climatic change and potential environmental and socioeconomic consequences.  Led to key international treaty- reduce global warming and cope with the consequences of climate change.

National Government Action

  • Climate Change Act 2008- britain 1st country to set legally binding carbon budgets to cut UK emissions. 
  • Carbon Trust- set up in 2001 by UK government as an independent not-for-profit company with the aim to accelerate the move to a low-carbon economy.
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1.5 Strategies to address Climate Change Extended

Local Policies

  • Keep Leicester Cool- Set up in 2003, 3-year campaign, using print and broadcast media targetting specifically Asian audiences (30% of local population)
  • CarbonNeutral Newcastle- 2003, city-wide initiative to raise awareness and reduce carbon emissions
  • Sustainable  Energy Action Plan- Swansea, aims to reduce carbon emissions to meet UK targets.

Pressure groups and individuals

  • Greenpeace- spur national government and international organisations into action.  Campaigns against 3rd runway at heathrow and development of new coal-fired power stations.  Support energy conservation and renewable energy
  • Friends of the Earth- 1971, safe climate locally, nationally & internationaly.
  • Global Warming Policy Foundation- set up 2009 by politician Nigel Lawson as a climate change septic think tank.
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1.6 Success of tackling climate change

  • Kyoto Protocol- failed expectations because; USA & Australia didn't sign and ratify the treaty; many countries have not met their agreed aims; many countries, e.g. Russia, not required to make reductions
    • Did establish a framework for a future climate agreements
  • UN Climate Change Conference- December 2009 aimed for 77 countries to cut greenhouse gases.  However, talks broke down and only 5 nations signed. 
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