carbon

geography paper 1

natural carbon cycle

movement + storage of carbon between the land, ocean+ atmosphere- forms of carbon include inorganic (found in rocks as (bi)carbonates), organic (found in plant material + living organisms) or gaseous (found as co2 and ch4 - methane). store of carbon are terrestrial, oceanic or atmospheric + fluxes are the movement of carbon between these stores.

generally, there is a balance between production and absorption (or sources + sinks) of carbon in the natural carbon cycle, however it can, sometimes, take a long time to reach equilibrium e.g. after a volcanic eruption

stores of carbon cycle

a carbon sink is a store that takes in more carbon than it emits, e.g. a healthy tropical rainforest, while a carbon source emits more carbon than it stores, e.g. a damaged tropical rainforest.

carbon is stored in the atmosphere as co2 + methane, the hydrosphere as dissolved co2, the lithosphere as carbonates in limestone and fossil fuels (coal, gas + oil), and in the biosphere as living + dead organisms.

carbon sequestration

the transfer of carbon from the atmosphere to other stores → can be natural or artificial. e.g. a plant sequesters carbon when it photosynthesises + stores the carbon in its mass

main stores of carbon (biggest to smallest)

• marine sediment + sedimentary rock (lithosphere) - longterm and 66,000 - 100000 mil bil tons of carbon → rock cycle + continental drift recycle the rock over time, but may take thousands - millions of years

• oceans (hydrosphere) - dynamic and 38,000 bil metric tons of carbon → constantly being used by marine organisms, lost as an output to the lithosphere or gained as an input from rivers + erosion

• fossil fuel deposits (lithosphere) - longterm/currently dynamic and 4000 bil metric tons remain → used to rarely change over short time, but development of technology = rapid exploitation

• soil organic matter (lithosphere) - midterm and 1500 bil metric tons → can store carbon for 100+ years but deforestation, agriculture + land use change impacts this

• atmosphere - dynamic and 750 bil metric tons → human activity has rapidly increased co2 levels in the atmosphere = unprecedented climate change

• terrestrial plants - (biosphere) - midterm but dynamic and 560 bil metric tons → vulnerable to climate change + deforestation so annual decline of carbon storage in forests around the globe (focused on the tropics + northern hemisphere)

lithosphere → main store of carbon + global stores are unevenly distributed

fluxes of the carbon

transfers in the carbon cycle act to drive and cause changes in the carbon cycle over time → all have impacts of varying significance over different periods of time. biological + chemical processes determine how much carbon is stored + released. the role of living organisms is very important in maintaining the system running efficiently.

carbon flux: photosynthesis

living organisms convert carbon dioxide from the atmosphere + water from soil → oxygen + glucose using light energy. by removing co2 from the atmosphere, plants sequester carbon + reduce the potential impacts of climate change + maintain the balance between oxygen + co2 in the atmosphere.

plants photosynthesise during the day → absorbing significant amounts of co2

carbon flux: respiration

occurs when plants + animals convert oxygen + glucose into energy, with the waste products of co2 + water

plants respire at night → releasing co2, but overall, plants absorb more co2 than they emit → net co2 absorbers + net oxygen producers

fastest cycle - within seconds, but can slow down when light levels or co2 drop

carbon flux: combustion

when fossil fuels + organic matter, e.g. trees, are burnt, they emit co2 into the atmosphere that was previously locked inside of them. this may occur when fossil fuels are burnt to produce energy or if wildfires occur.

carbon flux: decomposition

when living organisms die, thye are broken down by decomposers (e.g. bacteria and detritivores) which respire, returning co2 into the atmosphere. some organic matter is also returned to the soil + stored, increasing carbon matter. the soil may hold carbon for hundreds of years, some buried so deeply that they don’t decay or are buried in conditions that stop decay (low-lying gas, too much water) → becomes sedimentary rock or hydrocarbons

carbon flux: diffusion

oceans can absorb co2 from the atmosphere, which has increased ocean acidity by 30% since the pre-industrial period. ocean is the biggest carbon stores → but carbon levels increasing means more acidic seawater, harming aquatic life + causing coral bleaching

carbon flux: sedimentation

can happen on land or in sea → when shelled marine organisms die, their shell fragments fall to the ocean floor + become compacted over time to form limestone. organic matter (vegetation or decaying marine organism) is compacted over time to create fossil fuel deposits.

carbon flux: weathering + erosion

inorganic carbon is released slowly through weathering - rocks are eroded on land or broken down by carbonation weathering (when co2 mixes with rain to create carbonic acid → erodes rocks e.g. limestone). the carbon is moved through the water cycle, enters the oceans → marine organisms use the carbon in the water to build their shells. increasing co2 levels in atmosphere may increase weathering + erosion → impacts other parts of the carbon cycle

carbon flux: metamorphosis

extreme heat + pressure forms metamorphic rock → carbon is released but some becomes trapped

carbon flux: volcanic outgassing

there are pockets of co2 found in the earth’s crust. during a volcanic eruption or a fissure in the earth’s crust, co2 is released

complex carbon processes - ocean sequestration

oceans are the largest carbon sink (store 50x more than atmosphere) + large amounts of carbon are stored in oceanic algae, plants and coral → the transfer of co2 into the sea is ocean sequestration (lots of processes occur simultaneously to store this). gas exchange between the atmosphere + ocean operate on different timescales. small changes in oceanic carbon levels = significant global impacts.

most ocean sequestering processes occur in the top surface layer of the ocean (small proportion) = this carbon rich surface is transferred deeper into the ocean + transported around the globe by thermohaline circulation → this allows large amounts of carbon to be stored in the sea

complex carbon processes - biological carbon pump

phytoplankton are microscopic organisms that photosynthesise, taking in carbon + turning it into organic matter → only 1% of the world’s photosynthetic biomass but almost half of the total primary production. phytoplankton are the base of the marine food web → carbon is passed through the food chain + each organism respires, releasing more carbon

some organisms, like plankton, sequester co2 + turn the carbon into hard outer shells + inner skeletons, when these die their shells dissolve into the ocean water → carbon becomes part of deep ocean currents. any dead organism that sink to seafloor are buried + compressed, undergoing sedimentation and can become fossil fuels. (may be referred to as carbonate pump)

some co2 from the atmosphere will naturally dissolve into the water - occurs on the ocean surface + makes the ocean more acidic → could have longlasting impacts

complex carbon processes - physical pump

surface layer of ocean may become so saturated with carbon that this process would slow down or stop occurring → however, oceanic circulation provides a constant source of new water on the surface while transferring surface water to the deep ocean → enables the ocean to store so much carbon. co2 concentration is 10% higher in the deep ocean vs the surface.

carbon is not stored evenly - colder water absorbs more co2 → concentration of co2 in oceans changes across the world e.g. polar regions hold more carbon that tropical (releases co2 to the atmosphere)

complex carbon processes - thermohaline circulation

ocean current that produces vertical + horizontal circulation of cold + warm water across the globe + creates large currents in the ocean which transfers water from the warm to colder regions

rate of circulation is slow → ~1000 years for one cubic meter to travel around the entire system. warm surface water are depleted of co2 + nutrients → foundation of the planets food chain depends on cool = nutrient rich water to support growth of algae

water in the north atlantic is cold + saline = denser + heavier → sinks, so warm water is drawn from the surface, eventually cold water is drawn from the bottom of the ocean + warmed up

1. main current begins in polar oceans where water is cold + surrounding seawater sinks due to higher density

2. current is recharged as it passes antarctica with extra cold, salty + dense water

3. division of the main current → north in indian ocean + into western pacific

4. two branches warm + rise as they travel north → loop back south + west

5. the warm surface water continues to circulate around the globe, eventually returning to the north atlantic where they cool + cycle restarts

rate of absorption of co2 into oceans depend on ocean temperatures (colder ocean = more absorption), therefore as ocean temepratures increase, the oceans absorb less + possibly emit some of its store. this accelerates climate change + leads to further ocean warming (positive feedback).

the role of oceans in regulating climate + greenhouse gas emissions are essential to earth.

complex carbon processes - terrestrial sequestration

primary producers sequester carbon through photosynthesis - all living things either release or intake carbon

• primary producers (plants) take carbon from the atmosphere (photosynthesis) and release during respiration

• vegetation growth based on water, nutrients + sunlight

• when consumers eat plants, the carbon → fats + protein

• micro-organism feed on waste material from animals + plants

• animal + plant remains are easier to decompose than wood + decomposition is faster in tropical climates (high rainfall, temperature + oxygen levels)

• 95% of a trees’ biomass is co2, which is sequestered + converted to cellulose - amount of carbon stored in trees depends on the balance between photosynthesis and respiration

carbon fluxes due to terrestrial organisms vary

• day vs night - during the day, fluxes are positive while during the night, fluxes are negative (from atmosphere to ecosystem)

• seasonally - northern hemisphere during winter → plants die + decay, leading to high atmospheric co2 concentrations, but during spring - when plants grow - co2 levels in the atmosphere drop

forest loss + gain → impacts carbon store

forests are declining in the tropical regions of the southern hemisphere (e.g. brazil + indonesia) and growing in the northern hemisphere (russia, usa, china)

• non-tropical forests are increasing in carbon sequestration (e.g. europe + east asia) due to afforestation of agricultural land + plantations

• forests in industrial regions are expected to increase by 2050 → opposite for developing countries

• rate of forest loss in 1990s - 9.5mil hectares per year, around 4.7mil by 2020

• countries with largest forested areas: russia, brazil (most carbon stored on land + most extensive deforested area), china (most afforested), canada, usa, drc, australia + indonesia

• net primary productivity (npp) - amount of carbon absorbed by forests → positive all year round for tropical, but for deciduous - negative in winter, by positive on average

complex carbon processes - soil’s capacity to store carbon

• 20-30% of global carbon is stored as dead organic matter in soils for years, decades or even centuries in colder climates + wetland environments.

• any carbon that is not stored is returned to the atmosphere by biological weathering across several years.

• all plants are made of carbon, so any plant loss to the ground (litter fall) means a transfer of carbon to the soil → important in arid/semi-arid soils

• longest process is the formation of humus - dark, rich colour + is 60% carbon

capacity of the soil to store organic carbon depends on:

• climate - influences plant growth, microbial + detritivore activity e.g. higher temperatures result in rapid decomposition

• soil type - clay-rich soils have a higher carbon content than sandy soil as clay protects carbon from decomposition

• the use + management of soils - soils lose carbon through human cultivation + disturbance → 40-90 billion tonnes of carbon lost since 1850

natural greenhouse effect

the earth’s temperature control system relies on greenhouse gases in the atmosphere → driven by incoming shortwave solar radiation. this allows life on earth - however as co2 + ch4 levels increase, more longwave radiation is trapped within the earth’s atmosphere - raising global temperatures.

around 31% is reflected by clouds + gases in the earth’s atmosphere + the remaining 69% is absorbed by the earth’s surface and oceans → 69% of this is re-radiated as longwave radiation back to space → re-radiated back to the earth by clouds + greenhouse gases

constant levels of co2 help to maintain stable average temperatures worldwide → prior to the industrial revolution, the natural greenhouse effect was constant:

• slow carbon cycle, volcanism + sedimentation have been fairly constant over the last few centuries

• natural exchanges between the slow + fast sections of the carbon cycle were relatively small

• small variations in atmospheric co2 up until the late 19th century

the enhanced greenhouse effect

since the 1750s, (industrialisation in the uk), global concentrations of greenhouse gases in the atmosphere have increased by over 25% → 92% in 2023 was due to fossil fuels. human activity has resulted in more carbon being released and less being absorbed:

• land use change - 10% of carbon release annually and impacts on short-term stores in the carbon cycle such as soil + atmosphere → amazon, 70% of deforestation is for cattle ranching → produces methane → global warming

• fertilisers + rice padi fields are significant sources of greenhouse gases as they release methane, increasing as productivity accelerates. grains + seeds are considered more sustainable + use less water

• deforestation - 20% of all ghg emissions, main impact is when the cyclthie is interrupted and the land is used for other purpose → reduces carbon sequestration + land becomes a carbon source, rather than a carbon sink

• urbanisation - impacts local + global carbon cycles by replacing vegetation + covering soils → urban areas occupy 2% of land mass, yet account for 97% of all human caused co2 emissions. cement is often used and this releases carbon dioxides (7% of annual carbon release) → searching for concrete recycling

• fossil fuel combustion - results in co2, sulphur + particulates released in the atmosphere

carbon is measured in gigatonnes or petagrams - 41billion gt in 2023

impacts of the increased greenhouse effect - temperature

amount of solar energy reaching the earth varies depending on location + is the main factor in determining climate temperatures. solar intensity increases towards the equator + decreases at the poles. albedo effect will also determine the temperature of a location → snow reflects while dark forests attract solar radiation

impacts of the increased greenhouse effect - climate

rising levels of co2 in the atmosphere are believed to be the main contributor to an increase in average global temperatures but increases vary:

• europe, average temperatures are expected to increase more than the global average

• the largest increases are expected in E + N europe in winter + N europe in summer

• annual precipitation is expected to increase is N europe, but decrease in S europe

• extreme weather events are likely to increase in both frequency and intensity

impacts of the increased greenhouse effect - precipation

solar radiation is the most intense at the equator so convectional rainfall is common (based on the ITCZ model) + high rainfall. rainfall occurs at subtropical highs + poles → when air submerges + cools, water vapour condenses into clouds + precipitation. when air rises, it heats up + moisture evaporates = dry weather conditions

impacts of the increased greenhouse effect - ecosystems

• ecosystems help to regulate carbon + water cycle, but global warming could impact the functioning of these ecosystems - biomes most at risk are the arctic + coral reefs

• species with low population numbers are already at high risk → evidence to suggest that there will be change in species’ population size, timing of reproduction + migration patterns

• marine organisms are also at risk - low oxygen levels + high rates of acidification, and coastal ecosystems + low-lying areas are at risk of rising sea levels

• arctic region is warming 2x faster than the global average - melting permafrost releases ch4 + co2 → increases ghg in the atmosphere → global warming, so more ice/snow melts = positive feedback loop

• arctic tundra has changed significantly → rapid warming during the summer has lead to shrubs + trees growing (shouldn’t be able to) + the red fox now competes with the arctic fox for food + territory

• some studies show that when permafrost melts, the carbon may remain in the soil + warmer temperatures lead to more decomposition → releases co2

impacts of the increased greenhouse effect - hydrological cycle

• increased rate of evaporation could lead to more moisture being held in the atmosphere rather than the ocean

• increase in surface permafrost temperatures

• less sea ice + glacier storage

• change in capacity of terrestrial ecosystems

• change in river discharge - increased risk of flooding in winter + droughts in summer

energy security

maximum energy security refers to the uninterrupted availability of energy sources at an affordable price

• long-term energy security mainly deals with timely investments to supply energy sources that will match economic developments + environmental needs

• short-term energy security focuses on the ability of the energy system to react promptly to sudden changes in the balance between demand + supply

several key points to remember about energy security:

• generally evaluated at a national level → either secure or insecure

• considers 4 aspects of supply - availability, accessibility, affordability + reliability

• countries that are the most energy secure can meet their energy demand using their own supply - as opposed to imports

a good quality energy supply is consistent + secure + reliable throughout the year. it should be unlikely to experience geopolitical problems + there is little risk from changing climatic conditions or natural hazards. a good quality energy supply involves a diverse energy mix.

energy security is important for the functioning of a country + its economy as it operates important services such as transport, lights, heating, domestic appliances + manufacturing.

measuring energy usage

energy consumption is usually measured per capita (person) using:

• kilograms of oil per year (or equivalent) - kgoe/yr

• gigajoules per year/exajoules - ej/yr

• megawatt hours per year - mwh/yr

energy intensity is an alternative measure of how efficiently a country uses its energy (unit of energy per unit of gdp). high energy intensity indicates a high price/costs of converting energy into gdp → energy intensity decreases as development increases, as energy is used more efficiently + costs per unit of gdp reduces

energy mix

the energy mix refers to the range + proportion of energy produced by methods of production, including:

• non-renewable fossil fuels - coal, oil + gas

• recyclable fuels - nuclear energy, biofuels + general waste

• renewable energy - wind, solar + geothermal

today, the global energy mix is dominated by fossil fuels.

primary energy sources producing energy using raw materials, while secondary sources are modified primary sources to make them easier to use e.g. coal → electricity, or oil → petrol

primary energy sources

• coal - 27% of global energy production, usage is decreasing as china (main user) shifts away from coal to less polluting sources

• oil (petroleum) - 32% of global energy production, usage is still increasing as global energy demands increase - used most in usa, china + india and produced in russia, saudi arabia + usa

• natural gas - 22% of global energy production + half of coal’s carbon emissions → increasing year on year - used most in usa, china + russia and produced in usa, russia + iran

• uranium - very low carbon footprint + 4% of global energy production - mostly used in kazakhstan + greatest amount of nuclear fission energy produced in usa → likely to increase in usage worldwide

• biomass (may also be secondary) - used mainly in lics by burning organic matter (inefficient in making energy). when used in hic countries, its more efficient e.g. making biodiesel → has decreased in use worldwide

• hep - water drives turbines to produce electricity + very efficient + renewable - only a small percentage of global energy production → expecting global increase

• solar - usage is rapidly increasing every year as technology becomes cheaper - china has the largest installed capacity, though production is low due to climate.

• wind - other than hep + biomass, wind produces the most renewable energy - greatest production + capacity in china → spreading to lic countries + offshore is increasing too

• wave - very low generation, through developments in technology → may see a similar trend as solar + wind as technology gets cheaper

• tidal - too expensive so only a handful of installed tidal power schemes across the globe → swansea bay scheme abandoned due to the potential cost

• geothermal - very efficient + reliable + works all day/night + year-round, popular in countries with volcanoes + likely to increase as technology spreads to lics

global energy consumption varies - higher in the northern hemisphere as its more developed

energy players

there are key players who ave important role in securing energy pathways and controlling prices:

• they explore, exploit and distribute energy resources

• they own supply lines + invest in the distribution + processing of raw materials

• they respond to market conditions to increase the profits

most energy players are tncs - although there are expections such as russia’s state run gazprom. key energy players include: saudi aramco, russia gazprom, bp (uk), shell (uk-netherlands), exxonmobil (usa), petrobras (brazil) and petrochina.

tncs are the most prominent energy players, as:

• some tncs have more economic value than a small country, enabling the company to take action and invest in large-scale projects that a country may not afford

• tncs can bypass political tensions and access sources otherwise restricted to other countries. a developing country trying to exploit an energy source in a lic could be seen as a threat

• tncs may be inclined to invest in local infrastructure, logistics + development of workers’ villages. this benefits all - tncs benefits from faster transport links + happier workforce while the government receives “free” investment.

howveer, tncs are not always beneficial - may encourage environmental degradation, exploiting workers + unsustainable transportation.

energy players: OPEC

OPEC is an igo with member countries which export oil + petroleum. OPEC producers control 81% of the worlds discovered oil reserves. their mission is to unify the petroleum policies of its members to ensure the stabilisation of oil markets. they also want to create:

• an efficient + regular supply of oil to consumers

• a steady income for producers

• a fair return for those investing in the industry

in the past, OPEC set quotas depending on the condition of the world economy. supplies were boosted when demand rose whilst supplies were cut if demand fell.

2012-2016, oil output was kept high to compete against usa (had sufficient oil through fracking) → flooding market = collapse in global oil prices.

OPEC has been accused of holding back production in order to increase prices → increase profits for oil exporting nations. this can harm developing countries, who need a lot of cheap oil to develop their economies and manufactoring

energy players: national governments

governments try to secure energy supplies for their country + regulate the role of private companies. eu governments are trying to reduce co2 emissions + reduce dependency on fossil fuels

energy players: consumers

consuemrs create demand with purchasing choices usually based on price - as a country becomes richer + more educated, the population’s shopping habits change to reflect their needs e.g. locally sourced, environmentally friendly, and a reliable energy supply during winter and extreme weather

for example, lots of energy companies now have tariffs on imported or non-renewable sources to reduce energy insecurity or carbon offset their energy. money raised on non-renewable energy can fund environmental work such as afforestation, research into carbon capture + storage. if consumers change their spending habits + only use these tariffs then companies will be encouraged to move towards more green energy → consumers can have an impact on tncs

the effect of human geography on energy supply

most countries are interdependent on energy sources - import energy from other countries → geopolitical implications + requires the cooperation of other countries.

1. production: energy is produced in the areas where the physical geography is suitable - e.g. china + 3 gorges dam → suitable for hep

2. processing: energy is either processed on site or there may be no need for processing. fossil fuels may need refining before or after being distributed

3. distribution: energy is distributed by pipeline, transportation or in the form of electricity. distribution methods may cross international border = geopolitical implications

any stage in the energy supply chain may be used by countries as a political tool to cause or resolve tension between countries → different countries have varying national interests.

a country may want to import gas from another to shift their energy mix away from coal at a low cost → may require a pipeline passing through a 3rd country, who may not want their natural landscape to be spoiled by a pipeline + they all want the best price possible → complicated geopolitical negotiations

tncs may influence this if they have good links - compensating for the pipelines or forced to spend to protect the natural landscape → though, this won’t benefit the tnc BUT it would provide a natural gas pipeline + build political relationships.

energy supply can be confusing as it can be influenced by physical + human geography, tncs, geopolitics, community groups + activists (GET A CASE STUDY)

the issue with achieving energy security

• fossil fuel supply: mismatch between supply + demand for fossil fuels - mainly due to wealth + development inequality, natural resource supplies + industrialisation. coal consumption is declining worldwide, more than other fossil fuels → over half the world’s oil comes from OPEC and north american nations. however, since europe has a large demand for oil (yet produces little) → oil must be transported + traded = further insecurity + tension

• energy pathways: many ways of transporting energy → but these have their individual weaknesses - pipelines are efficient in carrying billions of m³ of oil worldwide between countries → many depend on international agreements, so influence global politics. + around 50% of the worlds oil is transported using oil tankers through choke points (key areas in energy logistics - can be disrupted) → if blocked/threatened, the oil prices rise very quickly + can become insecure (e.g. russia + ukraine conflict)

• political conflict - conflicts and political altercations can severely limit energy security e.g. can lead to infrastructure destruction → restricts the flow of energy from source to use. disagreements between nations can limit energy security e.g. russia - has received several political sanctions, but is a major supplier = electricity shortages in europe

alternative fossil fuels

within the last decade, new + unconventional energy sources have become more realistic. some alternative aim to increase supply of fossil fuels, keeping energy prices low + improving energy security. however, some new alternative energy sources aim to reduce co2 and greenhouse gas emissions whilst still meeting demand.

unconventional fossil fuels:

• shale gas

• deep-water oil

• tar sands

unconventional fossil fuels: shale gas

extracted through fracking - has been majorly opposed by environmentalists (2021 survey - only 17% of the british population supported fracking), yet 26billion cubic feet of shale gas was extracted in 2022 in the us. fracking is a relatively new process of extracting shale gas. water, chemicals + sand are pumped into the ground to break up the shale, access the hydrocarbons and force them to the surface. horizontal drilling helps to remove the gas reserves.

advantages:

• less polluting than coal or oil

• requires large amounts of water

• could boost the economy - creates jobs, predicted to create 16,000 - 32,000 jobs at its peaks

• in the uk, the royal academy of engineers believe fracking can be made safe

disadvantages:

• wastewater needs treating due to the chemical contents + contamination

• may pollute groundwater aquifers, in the usa the water has become flammable due to pollution by fracking

• earthquakes of low magnitude may occur e.g. 2.9 magnitude earthqauke recorded in 2019, near the uk’s only active shale gas site in lancashire, → does not pose a risk to humans, but damages fracking infrastructure = leaks

• ipcc suggest it would be irresponsible to use shale gas

unconventional fossil fuels: deep-water oil

as oil supplies decrease, energy companies have begun extracting oil from deeper depths (oil-bearing rocks that are permeable enough to allow the oil to be pumped out directly), deep water oil faces larger risks during extraction + can spill during transportation

advantages:

• many engines + applies are designed to operate on oil, therefore to continue to extract oil would avoid large changes to many important engines (vehicles + planes)

• shale gas produces half the emissions of coal, which would reduce global emissions without completely eradicating fossil fuel use

• a large influx of readily available shale gas would drop electricity prices

• majority of shale gas is found in the us, which would improve the us’s economy + provide an alternative source to russian oil (BUT tension between uk + russia)

disadvantages:

• fracking faces large environmental opposition + can pollute deep water sources

• shale gas is still more expensive to produce than conventional gas

case study: bp oil spill 2010 - deepwater horizon oil

deepwater horizon oil spill exploded as the blowout preventer failed to seal a breach failed = loss of hydrostatic pressure + exploded, killing 11 crew members + released 134 million gallons of oil into the gulf of mexico

environmental impact:

• 167,00 turtles were killed + 2-7mil fish were affected

• 93 bird species were exposed to the oil = huge impact on the food chain

• erosion rates along the louisiana coastline doubled across an 100mile stretch

economic impact:

• spill reached $1bil in damages as it impacted many industries specifically shrimp + oyster industry on the louisiana coast

• visitor + tourist numbers have fallen as recreation, fishing, swimming + boating were no longer allowed around the coast

response:

• 48,000 people were involved with the 6500 vessels deploying approximately 2500 miles of boo to prevent the oil from spreading

• by the end of 2014, bp spent a total of $14bil on clean up, with workers devoting 70mil hours to respond + clean up

unconventional fossil fuels: tar sands

the extraction of petroleum from sands involves high energies + boiling water, which can leave periods of concentrated chemicals. tar sands have a large environmental cost, but can be lucrative in profit + employment opportunities

advantages:

• tar sand production creates economic growth + a large influx of jobs for rural regions

• fastest growing industry - producing bitumen (high value) for international exports

disadvantages:

• the process of extracting bitumen is water + energy intensive, producing a large volume of waste (12 barrels of hot water = 1 barrel of bitumen + 3 barrels of tailing pond waste)

• the liquid waste is left in tailing ponds, so water can be recycled after it separates from the clay + salts. however, tailing ponds may also contain sulfate, chloride + ammonia which may infiltrate the groundwater stores + other water sources

• open mining involves removing the top layer of vegetation + soils to access the bitumen-sands, destroying habitats

case study: tar sands - canada

why do we need alternatives to fossil fuel ?

as oil + gas reserves diminish, new reserves + technologies are being discovered to support further resource exploitation. currently new reserves are being discovered at a lower rates than they are exploited. environmental groups suggest fossil fuel exploration should stop immediately + renewable energy used instead. in countries like bahrain which are 75% reliant on oil for GDP, this is not an economically viable /sustainable solution.

renewable energy

likely to be an essential component of the future global energy mix as it has a low carbon footprint (most of the times), the technology is always improving + becoming more efficient. each renewable resource has advantages + disadvantages, though as time progresses - disadvantages will decrease as technology is improved. though, all have the disadvantage of being visually unappealing + causing minor disturbances to local environments = NIMBYISM

example of new developments in renewable technologies to research further:

• solar - concentrated solar power, solar powered roads, solar power roof tiles

• wind power - vortex bladeless, larger blades, offshore

• wave power - eco wave power, pelamis wave power

• tidal power - swansea bay (defunct), tidal stream, meygen tidal stream project

• geothermal - FORGE, enhanced geothermal systems (EGS)

but, not all countries have renewable energy sources due to their physical geography e.g. lack of rivers, wind, sun.

many claim that renewable energy can completely replace non-renewables but this is unlikely because:

• not all renewable energy sources provide the same amount of energy, you need more wind turbines that hydroelectric dams

• oil prices in 2015 dropped significantly + as renewables are generally more expensive, they became less attractive

• some forms of renewable energy have negative impacts e.g. HEP could lead to large swathes of land getting flooded

solar power

panels that converts the sun’s energy into electricity

advantages: costs are decreasing rapidly, large potential in desert areas

disadvantages: not very efficient yet (15-22%) → 40-40% panels available, but expensive. effectiveness depends on climate + time of year + time of day

wind power

wind rives large turbines + generators that produce electricity

advantages: low running cost, can be used year round, plenty of suitable sites

disadvantages: bird life can be affected + depends on weather

wave power

waves force a turbine to rotate + produce energy - or a similar method

advantages: produce most electricity during winter → during high demand, pioneer projects are commencing across the globe

disadvantages: very expensive + a “perfect” solution is yet to be created, needs to survive storms

tidal power

incoming tides drive turbines in similar way to hydropower

advantages: has significant potential, reliable source of energy once installed

disadvantages: very expensive, few schemes currently operating in the world, impacts marine life

geothermal

water is pumped beneath the ground to hot areas + the stream from the water drives turbines to produce electricity

advantages: low maintenance costs, can work where other technology may not

disadvantages: high installation cost, risk during earthquakes

nuclear power

considered to be recyclable, since little uranium is needed to produce large amounts of energy through fission. despite being the most realistic option for replacing fossil fuels, there are some risks to nuclear energy:

• nuclear disasters like chernobyl + fukushima (mainly due to mismanagement) could happen again

• the risk that nuclear powered stations may be infiltrated during conflict or by terrorists

• radioactive waste has to be disposed of safely, often through vitrification in underground caverns

• the technology involved is only accessible for developed countries. operational costs are quite low but construction + decommissioning costs are extremely high.

• energy security may be compromised if countries own + fund nuclear plants in other countries (uk nuclear plants are owned by french + chinese tncs)

advantages:

• very low carbon footprint

• high efficiency

• safety always improving

• may have fewer negative impacts than fossil fuels

• technology becoming more affordable + accessible for nic’s

disadvantages:

• large-scale disasters do occur

• produces radioactive waste which is difficult to dispose of

• very high cost

• lack of support from general public

biofuels

in theory, are a good alternative to fossil fuels → process of burning biofuels is carbon neutral (taken in during photosynthesis = released during combustion). hwoever, worldwide forests have been cleared to plant oil palms (malaysia) + oilseed rape (eu) + maize (usa) to manufacture biofuels → many environmental implications with deforestation for biofuels - loss of biodiversity + habitats, reduced vegetation to intake co2.

clearing land to grow biofuels will create food insecurity - many swiss, swedish, american comapnies have bought land in order to grow biofuel crops but this has inflated land prices. shortage of food in 2001 in mexico lead to the tortilla riots as corn was bought by tncs to produce biofuels for cars - which increased the price of corn making it unaffordable for mexican families to buy to eat.

strengths: renewable energy source, lower emissions than fossil fuels (carbon neutral), can be grown very easily

weaknesses: takes land that food can be grown on, requires fertilisers + pesticides, requires large volumes of water, loss of carbon sinks as forests are destroyed to make way for plantations

opportunities: provides rural inward investment + local development project, positive multiplier effect, fuel earns export income

threats: biofue production will reduce food production, leading to future food insecurity, water sources may become contaminated with chemicals, where a biofuel source is also a food (e.g. corn, maize), food prices can increase when shortages occur

reducing carbon emissions

several strategies to try to take some co2 out of the atmosphere or reduce emissions → but can be expensive + must be carried out on a national scale to take effect.

carbon capture + storage (ccs) is a tech strategy used t capture c02 emissions from coal fired power stations → gas collected from the power plant, compressed + stored into underground aquifers or disused mines. CCS could reduce carbon emissions by 19% - only few schemes exists as it is expensive.

hydrogen fuel cells - provide an alternative to the use of oil. hydrogen is the most abundant element in the atmosphere but it usually combines with other elements especially carbon. therefore, hydrogen needs to be separated + stored before use. fuel cells convert chemical energy found in hydrogen into electricity + this produces pure water as a by product. these fel cells are much more efficient than petrol engines.

deforestation

forests cover around 30% of the earth’s land area, forests intercept rainfall + increase groundwater storage. a loss of even a small number of trees can disrupt weather patterns which could lead to more intense flooding + droughts

more than half of forested land is cleared due to increased for commodity production: soy, palm oil, beef + paper production. land is also being converted to build dams + reservoirs, therefore land clearing may increase as energy demands increase or water supplies decrease.

over ⅓ of all global forests have been cleared, annually around 13mil hectares are lost every minute.

impact of deforestation on the water cycle

• less interception so more surface runoff + shorter lag time

• shorter lag time will increase flooding risk

• more soil erosion as there are no tree roots to bind soil together

• eroded material in rivers

• less evaporation from vegetation

impact of deforestation on the carbon cycle

• reduction in carbon stored in the biosphere

• reduction in carbon absorbed for photosynthesis

• more carbon released from combustion

regional trends of deforestation

• 90% of forests in the uk + usa were lost through deforestation by the 19th century

• boreal forests have been threatened in russia + canada for oil + tar sands production

• in africa + south america, most forests have halved in area since the 1960s

• in indonesia, large areas of forest land have been cut down or burnt to make way for palm oil plantations for which demand is increasing significantly

implications of deforestation for human wellbeing

over 1.6bil depend on forests + more than 90% of these people are amongst the poorest in society. many people join pressure groups (greenpeace + wwf) to oppose forest loss. greenpeace found that tncs don’t do enough to prevent deforestation, forest fires + human rights abuses.

grassland conversion

main types: temperate grasslands (which have no trees) + tropical grasslands/savannas which have trees but infertile soil.

role of grasslands:

• traps moisture + floodwater

• absorb toxins from soil

• provide cover for dry soils

• provides habitats for wildlife

• acts as a carbon sink

impact of grassland conversion on carbon cycle → converting grasslands into agricultural farms will:

• release co2 into the atmosphere

• there is a net increase in co2 emissions as biofuel crops need fertilisers

• cultivated soil is more susceptible to erosion

ocean health

oceans absorb around 30% of the atmosphere’s co2. since 1800, around 50% of all carbon emissions came from the combustion of fossil fuels. as co2 in the ocean increases, the pH of the ocean decreases (increasing acidity).

overfishing is also creating imbalanced in ocean health, threatening ocean security in the future:

• fishing supports 500mil people of which 90% live in LDCs

• fish is a cultural choice for wealthy MEDCs whereas it is a necessity for people in LEDCs

• millions of small-scale fishing families depend on seafood for their income as well as for food

in addition to fishing, many countries rely on their marine life to attract tourism. therefore overfishing + acidification (affecting coral reefs) can have direct consequences for a country’s economy + employment.

impacts for wildlife: as oceans become more acidic, coras cannot absorb alkaline caco3 in order to maintain their skeletons, in turn reefs begin to dissolve. algae provide food to corals through photosynthesis. uf the water becomes warm enough, the algae leave the coral, leaving the coral to turn white (coral bleaching)

coral reefs:

• shelter 25% of marine species

• protect shorelines

• support fishing industries

• provide income through tourism

climate change + its impact

increased carbon emissions are enhancing the greenhouse effect significantly + this impacts the world’s climate

impacts on water cycle + climate:

• more frequent + more intense storms/hurricanes

• rising sea levels, therefore more coastal erosion + some land lost (isostatic sea level rise)

• more frequent floods, droughts + heatwaves

changes in ocean currents + atmospheric circulatiopn could have an impact ion patterns of precipitation, evapotranspiration + temeperature

scientists have used climate model dimulations to investigate shifts in climate zones - they believe that for an increase of 2 degrees, 5% of the earth’s land area shifts to a different climate zone

impacts on the carbon cycle: due to climate change, globala verage temperatures are predicted to rise (global warming) which will lead to:

• more co2 released from boreal forests as they become drier + forest fires start

• ch4 from thawing permafrost

• ch4 from the destabilisation of wetlands

loss of arctic albedo (white snow reflects solar radiation, earth + dark surfaces will absorb solar radiation) may lead to increased permafrost thawing. if some arctic bogs thaw, huge quantities of methane + co2 gas will be released into the atmosphere, leading to irreversible changes to climate

climate change - summary

greenhouse gases are likely to increase in the future as more countries industrialise and develop. greenhouse gases remain in the atmosphere for a long time → if the global emissions reduce, surface air temperatures continue to rise.

it is very difficult to predict future emission levels → scientists use various scenarios to show projected greenhouse gas concentrations = several uncertainties as models cannot predict anything BUT have identified several tipping points + feedback mechanisms that would accelerate climate change. AND models are becoming more accurate → can predict a temperature increase of 2^o minimum

why is there uncertainty over climate change + what do future emissions models predict?

• oceans + forests are carbon sinks + store heat energy

• oceans take a very long time to respond to atmospheric changes → so they will continue to affect the global climate for a long time if/when human emissions slow

• increasing forest cover will make a more efficient carbon sink, in HIC countries there is evidence of afforestation

• weather will have a direct influence over vegetation productivity + the rate of chemical reactions. future vegetation changes are also unknown

alternatively, human factors will create the most uncertainty in predictions:

• economic growth is not always steady - financial events such as the 2008 crash affect rates of emissions + covid 19 lowered co2 in the atmosphere

• population change - increasing affluence in emerging economies mean that by 2050, there could be an additional 1bil consumers = more emissions as there is more energy consumption

• technology + globalisation - increased globalisation leads to more travelling + transportation of goods which could mean more emissions. however, technological advancements may compensate + decrease emissions created by the interconnected world as countries may embrace/reject green tech

• energy consumption is still growing, however renewable energy is starting to become more significant in the energy mix.

feedback mechanisms

negative feedback dampens the original process whilst positive feedback amplifies the original process

positive feedback loops - creates changes:

• peatlands - peat is the accumulation of partly decayed vegetation, which stores a large amount of carbon. warming causes peat to dry out + the rate of decomposition increases. an increase of 4^o causes a 40% loss of soil organic carbon from shallow peat + 86% from deep peat. peatlands emit carbon in the form of methane which increases greenhouse gases + accelerate enhanced greenhouse effects.

• permafrost - when this melts, trapped carbon is released into the atmosphere as co2 + ch4 = increases greenhouse gas concentrations in the atmosphere. this leads to higher temperatures + further melting of ice

• simple examples - all the result of temperature rising:

  1. arctic ice melts

  2. amazon die-off → increase risk of droughts + wildfires → less trees

  3. clogging of the ocean sink → warming waters shut down exchange of co2

  4. subsea floor methane hydrate + warming wetland peat → releases greenhouse gases → more heat absorbed by atmosphere → temperature increase

negative feedback loops - reduces changes:

• le chatelier’s principle - shift in chemical equilibrium → 75% of co2 emitted by humans will dissolve into oceans over centuries

• chemical weathering - removes co2 from the atmosphere

• biosequestration - captures + stores carbon by biological processes → formation of shells by organism in the ocean, converting co2 to limestone

• net primary productivity - plant photosynthesis increases in response to increasing concentrations

tipping points

a climate tipping point is a critical threshold; when this threshold is reached, small changes in the global climate system can transform a stable system irreversibly.

• forest die-back - rainfall in the amazon is largely recycled. if there is a drought in the rainforest, trees may die. a tipping point could be reached when moisture can no longer be recycled (due to too few trees to intake moisture) → more trees dying. in the boreal forest ecosystem, hot + dry summers lead to water stress which can result in a loss of trees. a tipping point could be reached when trees no longer absorb as much co2 = increase ghg concentration in the atmosphere = drier summers

• thermohaline circulation - cold water in the north atlantic forms part of the thermohaline circulation → to keep warm water heading from the tropics towards britain, heavy water must sink in the north. the melting of northern ice sheets releases large amounts of freshwater into the ocean, whihc is less dense + has low salinity. this disrupts the circulation of water, impacting the temperature of the ocean → impacts the weather of the uk. believed by some scientists that thermohaline circulation is slowing down - if it stops, the world will go into an ice age.

how can adaptation strategies be used to cope with a changing climate?

adaptation strategies adopt new ways of doing things in order to cope with the effects of climate change:

• the extent of adaptations needed will depend on how much the climate warms up

• some are bottom-up style approaches which are low tech + low cost, whilst others are more technology advanced + require higher economic capacity

• in some countries, policies are easy to implement, but it is more difficult in certain places like china

• strategies need collaboration between different players to work properly

examples of adaptation

water conservation + management - due to limited supply of freshwater e.g. israel: smart irrigation, recycling sewage water for agricultural use, reducing agricultural consumption, importing water in food as virtual water (watermelon), adopting stringent conservation techniques, managing price for water → “real value” - reflects the cost of supply + of ecosystem management

benefits: