The Carbon cycle and Energy security - EQ3

Land-use cover: 

• deforestation and conversion of grasslands to farming is mainly occuring in NICs, LEDCs and MINT countries 
• afforestation in mainly MEDCs 

Deforestation:

• for temperate forests such as in the UK and USA, 90% was deforested by the 19th century 
• Boreal forests have been increasingly threatened since the 20th century e.g. by oil and tar sands production 
• tropical forests have lost half their area since the 1960s 

reduction in storage in soil and biomass, especially above ground 

reduction in CO2 intake through photosynthesis 

increased carbon influx to atmosphere by burning and decomposing vegetation 

infiltration is decreased 

run off and erosion are increased 

flood peak are higher and lag time is shorter 

annual rainfall is reduced 

increased discharge leads to floodin 

more sediment eroded and transported into rivers 

raindrop impact washes finer particles of clay and humus away 

heavier sands are left behind 

biomass is less due to reduced plant growth 

rapid soil erosion leads to a loss of nutrients 

increased leaching means that nutrients are lost 

Benefits: 

• trap moisture and floodwater 
• aborbs toxins from soils 
• maintain healthy soils
• provide cover for dry soils
• maintain natural habitats 
• act as carbon sink 
• terrestrial carbon store 

Disadvantages:

• initial removal of grasslands releases CO2 
• annual ploughing enable soil bacteria to release CO2 
• needs irrigation which impacts aquifers 
• cultivated soils are liable to erosion 
• reduces the lung effect 

• 2005, about 70 milion hectares of pristine forest in south-west Amazonia was damaged 
• treefall, dieback of braches, and reduced moisture volumes and biomass 
• despite higher rainfall by 2010 drought, trees had not recovered and were even more vunerable
• 2010 nearly half of Amazonia affected, 20% severly
• emissions increased during the droughts due to more frequent wildfires and decomposing dead wood 
• 2005 drought emitted 5 billion tonnes of CO2 
• 2010 drought emitted 8 billion 
  • more than the CO2 absorbed
• if the Amazon rainforest becomes a carbon source rather than sink it will accelerate global warming, climate change and change the biome - e.g. of positive feedback 

Forests provide:

• supports soil formation 
• wood and fibre 
• fuel 
• regulates climate, floods, disease 
• water purification 
• cultural value- asthetic/ educational 

Impacts of forest loss on humans:

• job loss- 11% of global incomes 
• reduction in food and nutrient security 
• water related risks- local floods, drought 
• increased air and water pollution 
• indigenous people rely on trees 
• fuelwood source for 1/3 of people globally for cooking and drinking water 

Stage 1 - rapid economic growth 

Stage 2 - concern about environmental degredation 

Stage 3 - action to protect the environment 

Short term impacts:

• with further sea-ice loss, increases in marine plants, such as, phytoplankton may cause a limited increase in the uptake of CO2 

Long term impacts: 

• carbon uptake by terrestrial plants is increasing because of longer growing seasons and migration of boreal forests 
• thawing permafrost storing methane will add to greenhouse gases in the atmosphere - CH4 is 25 times more powerful than CO2

Loss of Arctic albedo:

• high albedo in areas of un-thawed permafrost reflecting heat
• ice melting due to increase temperatures 
• forests begin to grow due to the warmer tempuratures and ice melting 
• low albedo of forest absorbs heat 
• warms ground increases loss of ice 

Carbon CO2 feedbacks: 

• tundra soils giving off CO2 emissions 
• leads to climate change 
• melting of permafrost, huge carbon store, gives off CH4 and CO2 
• low albedo of forests aborbes heat and some CO2, but less than being emitted 
• accelerates climate change 

Factors making predictions uncertain

Physical:

• oceans and forests act as carbon sinks 
• oceans take decades to respond to changes in greenhouse gas concentrations 
• their response could continue to affect the global climate for hundreds of years 

Human: 

• economic growth
  • emissions could decrease as economies develop 
  • however, energing economies could lead to an increase 
• energy sources
  • energy consumption grew 2% between 2008 and 2014
  • however, renewable sources made up 2/3 of the increase in electricity production in 2015
• population change
  • increasing affluence 

peat stores carbon 

low release of CO2 as decomposition is slow in cold, waterlogged soils 

warming 

peat dries out 

decomposition rate increases 

carbon and methand emitted 

increase greenhouse gases 

further warming 

Forest die back 

• rainfall in the Amazon Basin id largely recycled from moisture within the forest 
• if the rainforest experiences drought, trees die back 
• tipping point- when the level of die back actually stops the recycling of moisture 

• in boreal forest ecosystem the hot, dry summers lead to water stress and trees die back 
• tipping point- when the tress no longer absorb enough CO2, leading to increased levels of greenhouse gases 

Changes to the thermohaline circulation 

• cold, deep water in the North Atlantic forms part of the thermoline cirulation 
• to keep the circulation of warm water from the Tropics to Britain, heavy, salt water must sink in the North 
• melting of northern ice sheets releases large amounts of freshwater which is lighter and less salty, blocking the circulation 
• tipping point- when ice sheets melt the ocean circulation is susceptible to a tipping point 

2015 Paris agreement 

• 195 countries
• limit the average global tempurature increase to 1.5 degrees above pre-industrial
• report on the plans to reduce emissions 
• strengthen the ability to adapt to and be resilient in dealing with impacts of climate change
• provide adaption support for developing countries 
• continue to support initiatives in developing countries 

Water conservation management:

• strategies implemented to help manage the conservation of water 
• allows a supply of water to be stored for use in times of water/ food scarcity 
• efficiency anf conservation can't match increased demand for water
• China- water-saving irrigation put inplace in areas of huge demand, between 2007/8 the country saved up to 11.8% of its previous water consumption 

Resilient agriculture systems 

• use of early or late planting to create plants which can withstand high tempuratures
• crops can withstand an increase in tempuratures 
• higher- tech, drought-tolerant species help resistance to climate change, however, there are high energy coasts 
• Tibet- 

Land-use planning:

• development of floodplains limited to low-impact things, such as, playing fields/ parks
• ensures nothing of importance is within areas that could be floooded when climate change causes increased flooding 
• needs strong governance, enforcement and compensation/ can cause political issues 
• Bangledesh- high population density in its megacities making abandoning high-risk areas and land-use resettling unfiasible 

Flood-risk management 

• management of areas susceptible to flooding i.e floodplains 
• prevents damage to areas which see increased flooding 
• can invlove hand management, expensive 
• landowners demanding compensation for afforestation 
• constant maintenance 
• Austrailia- adapting to increased flood risk by making all housing or floodplains more flood- resistent with raised-floors, stronger pile foundations and water resistent materials

Solar radiation management 

• engineering methods which are used to intervene in the climate system to conteract global warming 
• reduces global warming as more of the sun's heat is being reflected so won't heat the earth 
• reduce but not eliminate the greenhouse effect messes with a complex system, could have consequence 
• untried/tested
• Spray seawater into the atmosphere would provide hygroscopic nuclei for condensation to take place, creating bright white clouds which reflect the sun's energy back into space

Carbon taxation 

• fee paid on fossil fuels, linked to the level of emissions that the fuel produces 
• gov taxes can encourage people and businesses to reduce carbon emissions by using less fuel or electricity 
• doesn't completely prevent emissions but helps to reduce it 
• UK- carbon price floor tax sets a minimum price companies have to pay and emit CO2- 2015 policy was frozen, lower road tax for low-carbon emission cars scrapped, oil and gas exploitation tax relief was expanded to support fossil fuels 

Renewable switching

• switching away from fossil fuels to low-carbon energy sources 
• reduces the level of carbon emissions, reduces the greenhouse effect
• Sweden- oil has fallen from provided 75% of energy in 1970 to 20%, 83% of electricity produced by nuclear, combined heat and power plants produce 10%, 7% from wind 

Energy efficiency 

• improving efficiency of energy usage to reduce wastage 
• prevents waste 
• reduces the negative environmental effects 
• Germany- policies for efficiency include: requiring residential and comercial buildings to reduce energy consumption by 25%, loans to renovate older energy consuming properties, subsidies to improve efficiency in manufacturing 

Afforestation 

• planting of trees 
• increase in the number of trees means that more CO2 will be absorbed from the atmoshpere and sequestered in plant leaves and roots 
• UK- planting of trees is increasing, helping carbon sequesteration, Big Tree Plant campaign encourages communities to plant 1 millionmore trees, mostly in urban areas 

Carbon capture and storage 

• capturing gas before it is emitted into the atmosphere and storing it underground 
• majorly reduces the greenhouse effect as majority of previously emitted greenhouse gases will be prevented from reaching the atmosphere 
• Canada- had the world's first comercial carbon capture coal-fired power plant, aims to cut emissions by 90% by trapping it underground before it can reach the atmosphere, expects to reduce greenhouse gas emissions by about 1 million tonnes per year