Climate Change

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

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

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

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.

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. 

(Diagram)

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

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

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.

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

• 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

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. 

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

Health

• 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

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. 

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

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.

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.

• 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.