Climate change

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  • Created by: 8cburton
  • Created on: 28-05-15 12:23

Physical evidence for climate change

HISTORICAL EVIDENCE- Indirectly show different conditions eg. agricultural reports, cave paintings, diaries, documents of events (like fairs on the Thames), since 1973 weather records

ICE CORES- Ice sheets made each year, analysing gases trapped when the ice formed and the chemitry of the air.  In cold periods there is less energy to evaporate so water molecules containing the lighter O2 evaporate easier. This O-16 rich water vapour is carried to the poles and falls as snow. (high levels of light O2 indicate cold climate)

SEA FLOOR ANALYSIS- sediments deposited on sea floor record the chemical composition of seawater. Contain oxygen isotopes. (high levels of O-18 indicate cold period due to O-16 evaporating). Also shows shifts in animal and plant species

SEA LEVEL CHANGE- submerged river valleys show sea level used to lower

RETREATING GLACIERS- looking at historical photos and position of rocks deposited by the glacier

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Biological evidence for climate change

POLLEN ANALYSIS- Pollen preserved in sediment can be identified and dated. Climate conditions identified by the plant living there. Oxygen free environments like peat bogs resist decay. One problem is that the pollen could be blow there or distributed by animals

COLEOPTERA- the remains of bettles whose remaines are easily preserved in sediments. Scientits build up picture of climate via distribution of coleoptera remians

TREE RINGS- rings are thicker in warm, wet conditions. can show climate up to 10,000 years

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proposed theories to climate change

  • variations in solar activity (sunspot activity)
  • changes in the earth's orbit and and oxial tilt
  • meteorite impact
  • volcanic activity (more dust in atmosphere)
  • changes in oceanic circulation
  • changes in atmospheric composition (build up of CO2)- allows incoming short wave radiation and warm th earth. Some of this radiation is reflected back and the green house gases trap the long wave infrared radiation warming the atmosphere. Without greenhouse gasses the earth would be 30 degrees colder

Burning fossil fuels- since the industrail revolution in the mid-19th century

Farming- methane from livestock and rice paddies, nitrous oxide emission from fertilizers

Deforestation- 50% removed in last 30 years, less CO2 absorbed and burning trees releases CO2

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Impacts

PATTERN OF PRECIPITATION TO CHANGE- wet areas will get wetter, precipitation will decrease by 5-10% in other areas due to changes in ocean circulation and wind patterns. Dry areas drier

GLACIERS, SEA ICE, ICE CAPS WILL MELT CAUSING SEA LEVEL RISE- global seal leve rise by 0.09-0.88 m between 1990- 2100

MORE EXTREME WEATHER EVENTS- storms, floods and groughts are more likely and more severe due to changes in ocean currents and winds

INDICENCE OF DISEASES AND ILLNESS COULD INCREASE- more people to suffer heat-related illnesses. Breathing problems due to increased air pollution in cities rises (rise in temp- rise in photochemical smog). Disease vectors may spread to regiion currently too cold. Food bourne illnesses may increase as temp rises

CONFLICTS OVER WATER RESOURCES COULD INCREASE- water supply will decrease by 10% by 2050

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More impacts

AGRICULTURAL CHANGES- Productivity will decrease in some areas (eg. spain will become desert like). Productivity will increase in other areas (more rain in N.america + europe), changes to the type of crop grown. Agricultural pest + disease may increase in some areas (corn borer moving further north as temp rises).

SPECIES DISTRIUTION WOULD CHANGE+ BIODIVERSITY DECREASE- Invasion of new species may damage ecosystems. Some habitat destroyed (poles, coral reefs, mangrove swamps)

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Changes to British climate

CLIMATE WILL CHANGE- temp rise by 3.9 by 2080, wetter by 35% on western side of UK, summer rainfall decrease by almost 1/2 in southern UK

SEA LEVEL WILL RISE- 13-76cm by 2095, worst affected areas would be estuaries and lowlying coast (Norfolk), more storms and storm surges causing coastal flooding

DROUGHT MAY INCREASE in south UK

PATTERNS OF AGRICULTURE ARE EXPECTED TO CHANGE- growing season increase so may increase productivity. Types of farming shift N. New crops for warmer climates (grapes, soya beans). Drought in south so more irrigation needed

HABITIATS WILL CHANGE- Species move N + higher elevations seeking cooler climate. Extinction of native species. Invasion and sread of alien weeds, pests and diseases. Increase number of foreign species which may out compete natives. disappearance of snow from the tops of the highest mountains

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Changes to monsoon climate in Bangladesh

  • Get hotter (average temp increase by 2-4 by 2100)
  • Seasons more pronounced winter droughts, rainer summer)
  • Intense rainfall causing flooding landlides and crop damage
  • Warmer sea causing more cyclones
  • Melting in the himalayas causing 20% increase in river discharge
  • Sea level rise in banagladesh will submerge 18% of the land making millions of people migrate which will cause overcrowding and tension to other nations
  • Flooded areas will suffer more cholera and hepititis
  • coral reefs will become damaged by storms which will have knock on effect to marine life
  • The Sundarbans are a cluster or islands off the coast have the worlds largest mangrove forests supporting endangered royal bhengal tiger, the Indian python and the estuarine crocodile. Climate change may lead to loss in this habitat as complete flooding of low-lying islands, retreat of shorelines, salinisation of the soil and rise in water table
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Kyoto protocol

  • International agreement formed in 1997. 190 countries have joined the agreement to monitor and reduce greenhouse gas emissions
  • Developing countries didnt have to cut emission but monitor them
  • Incentives introduced, carbon credits (countries and companies given a limit on how much they can produce- if they produce less they can sell extra and if they over produce they can buy more
  • They can also gain credits by helping reduce emissions in developing countries
  • 4 countries with high emission (USA, Australia, China, India) didnt sign up as USA and Austalia felt is would affect their economies + that developing coutries should have the same targets. China and India though it would slow their growth rate.
  • Australia, India + China have now joined but theres lots of criticism. some people think the targets arnt high enough and some think there is no point is th highest polluters arnt included (USA still not fully joined).
  • Countries fail to meet targets- many cases emissions are still increasing

The Kyoto protocol ended in 2012 + world leaders met in 2009 to reach a new agreement- the Copenhagen Accord. Each country allowed to set its own targets for cutting emissions, however it is not legally binded so there are no penalties for countries which miss their targets.

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National responses

  • Mix of energy sources (fossil fuels, nuclear power and renewable energy)
  • France gets over 1/2 of its energy from nuclear power while the UK gets most from fossil fuels
  • In UK around 40% emission reductions by 2020 will be achieved by changing the energy mix. The aim is to produce 30% of our energy from renewable sources by 2020
  • More offshore wind farms are being built, several wave and tidal power projects are planned and more electricity being generated by solar radiation, wind and biomass
  • UK government encouraging small scale renewable energy projects eg. relaxing planning laws to make it easy for people to install solar pannels

BUT...

  • There needs to be more investment in nuclear power and renewable energy, we still rely on fossil fuels
  • There are also environmental problems with nuclear power and renewable sources eg, dangerous waste + tidal power can disrupt coastal ecosystem.
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Using tehcnology to cut emissions

  • carbon capture+ storage (CCS) captures emissions from power stations and stored in deep geological formations.
  • Has the potential to cut emissions by 90%

BUT

  • Still at developmental stage + several problems have been found
  • CCS uses fuel + increases cost of energy
  • There is also risk of stored CO2 to leak.
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Energy conservation at home

  • reduces domestic fuel consumption
  • By 2020 15% of emission rductions will be made by making homes more energy efficient. Government strategies include providing energy efficiency grants to help people pay for saving
  • Financial incentives are being offered to encourage people to generate their own electricity from renewable sources
  • Homes being sold need an energy performance certificate that shows how energy efficient the home is

BUT...

  • Energy saving improvements can have high intial costs
  • Its difficult to work out how energy efficient some houses are
  • there are regulations restricting the improvements that can be made on listen buildings
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reducing emissions from transport

  • In the UK around 20% of emission reduction by 2020 will be achieved by reducing emissions from transport. Strategies include encouraging people to buy lower emissions vehicles eg. road tax is free for cars emitting up tp 100g COs/Km but costs £475 a year for cars emitting over 255g
  • Financial incentives for electric cars/ hybrid eg. governemtnal grant of up to £5000 is available for people buying cars that emmit less than 75g CO2/KM
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Local responses

RECYCLING WASTE- in the UK recycle prevented the release of 10-15 million tonnes of CO2 every year. BUT transporting wate creates emissions so important to develop local facilities

USING CARS LESS- walking/ cycle more, public transport + car sharing BUT people prefer cars

BUYING LOCAL- Local produce reduces food miles eg. aircraft very high emissions compared to shipping. Heating greenhouses to grow produce out of season have high energy consumption so eating seasonal produce + importing less food could save millions of BUT many people like to have acess to a variety all year.

CHOOSING ENERGY EFFICIENT APPLIANCES- Modern appliances are 50% more efficient than older models. If everyone in the UK upgrade their fridges it would prevent 3.7 millions tonnes of CO2 every year. BUT throwing anway old appliances creates alot of waste, making new appliances uses energy and people may be reluctant to spend money on new appliances.

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