The Carbon Cycle and Energy Security

The Carbon Cycle and Energy Security flashcards

Carbon Forms

Atmosphere - Gaseous

• As carbon dioxide (CO₂) and carbon compounds such as methane (CH₄)

Hydrosphere

• Dissolved CO₂

Lithosphere - Inorganic

• As carbonates in limestone, chalk and fossil fuels

• As pure carbon in graphite and diamonds

Biosphere - Organic

• As carbon atoms in living and dead organisms

Geological Carbon Cycle

Geological carbon is a large carbon store, consisting of carbonate sedimentary rocks

• There is over 100 million Pg of carbon in the lithosphere

Geological carbon cycle

• CO2 dissolves in rainwater to form carbonic acid, which reacts with silicate sedimentary rocks on Earth’s surface when it rains, breaking it down into ions (chemical weathering)

• The ions and other carbon rich sediments derived from shells, coral and plankton settle on the sea floor, sediment gradually building on top over time crompressing it down. Over millions of years the sediment is subjected to immense pressures it becomes lithified and gradually becomes solid rock (sedimentary rock)

• These sediments have been uplifted by tectonic processes, and the carbon they contain have been weathered, eroded and transported back to the oceans

• Pockets of CO2 existing within the earths crust can be releaed by volcanic outgassing and earthquakes, mainly occuring along mid-oceaninc ridges, subduction zones and hotspots.

The Himalayas form one of the Earth's largest carbon stores

• 80% of lithospheric carbon is found in limestones

Terrestrial Carbon Cycle

Relating to the land

On land, soils are the biggest stores of carbon, stored in the form of dead organic matter that can be stored for decades to centuries before being broken down by soil microbes and then either taken up by plants or realeased back to the atmosphere

• Carbon is sequestered from the atmosphere through photosynthesis by plants. This carbon is then stored within the plant until it dies and decomposes, transferring carbon to the soil via leaf litter and roots. Bacterial action in decomposition releases carbon back into the atmosphere through soil respiration

• Alternatively, organisms eat the plants and some of that carbon is released back to the atmosphere through respiration

Factors influencing speed of terrestrial sequestration

• Time of day (more photosynthesis in daytime)

• Time of year (more photosynthesis in summer as warmer temperatures speeds up rate of photosynthesis)

• Precipitation (more rainfall supports more plant life, more droughts support less)

• Deforestation/afforestation

Factors influencing soils capacity to store carbon

Soils store 20-30% of global carbon

Soil type

• Soil with high organic matter content, like peatbogs, have higher carbon storage capacities

• Clay protects carbon from decomposition, so clay-rich soils have higher carbon content

Vegetation and land use

• Forests, wetlands and grassland tend to have higher carbon storage than croplands and urban areas, supplying more dead organic matter

Climate

• Generally wetter and warmer climates support higher rates of vegetation growth (Net Primary Productivity - NPP) and decomposition rates, leading to higher soil carbon turnover

Soil pH

• Soil pH affects microbial and organic matter decomposition rates, influencing soil carbon capacity. Neutral to slightly acidic soils generally support higher carbon storage compared to highly acidic or alkaline soils

Carbon stored within mangrove, tundra and tropical soils

Mangrove

• Mangrove forests sequester 1.5 metric tonnes of carbon per hectare every year

• Mangrove soils consist of thick layers of litter, humus and peat which contain high levels of carbon (over 10%)

• Submerged below high tides twice a day, Mangrove soils are anaerobic, meaning bacteria and microbes cannot survive, so decomposition of matter is slow

• As a result carbon cannot be respired back into the atmosphere and the store remains intact

• Any plant matter trapped by tree roots tends to stay as it decomposes slowly, and may remain stored for thousands of years

• If Mangroves are drained or cleared (shrimp farms and agriculture), carbon is released back into the atmosphere

Tundra

• Tundra soils are mostly permanently frozen, locking in ancient carbon from dead and decayed organic matter.

Tropical Rainforests

• Tropical rainforests are massive carbon sinks, mainly stored in trees, plant litter and dead wood, but are fragile and can quickly disappear

• Soils are relatively thin and lacking in nutrients due to the litter layer that covers them decomposes rapidly and the nutrients released are rapidly consumed by vegetation

• Therefore, soil stores do not develop

• Tropical rainforests account for 30% of global net primary production (NPP), although they cover just 17% of the Earth’s surface.

Ocean Sequestering

Biological Carbon Pump

The oceans are the Earth’s largest carbon store, with 93% stored in undersea algae, plants and coral, with the remainder in a dissolved gaseous form

• Phytoplankton sequester carbon from the atmosphere through photosynthesis (and produce half of all the oxygen in the atmosphere)

• Zooplankton (e.g. Krill) eat the phytoplankton and assimilate the carbon, and other predators eat the the zooplankton etc.

• They drop fecal matter / die and sink as aggregates (marine snow), carrying organic carbon from the surface to the deep ocean

• Carbon is then buried in sediements and stored on the sea floor for extended periods of time

The Carbonate Pump

• Forms sediment and eventually rock from dead organisms that fall to the ocean floor

Ocean Sequestering

Physical Carbon Pump

• Moves carbon to different parts of the ocean in downwelling and upwelling currents

• Downwelling occurs in parts of the ocean where cold, denser water sinks, bringing dissolved CO2 down to the deep ocean

• Once there it moves in slow-moving deep ocean currents, staying there for hunderds of years

• Eventually these deep ocean currents, part of the thermohaline circulation, return to the surface by upwelling

• The cold deep ocean water warms as it rises toward the ocean surface and some of the dissolved CO2 is released back into the atmosphere

Thermohaline Circulation

The global system of surface and deep ocean currents driven by temperature and salinity differences between different parts of the ocean

It can be seen as a giant conveyor belt, which plays a vital part in the carbon cycle

• It takes 1000 years for any cubic metre to travel around the entire system

• Surface waters are warmer and depleted in carbon and nutrients

• Deep waters are colder and contain more carbon and nutrients 

• The circulation helps take carbon in the carbonate pump to deeper ocean stores

Cold polar waters are far better at absorbing atmospheric CO2. Rising ocean temperatures due to climate change are reducing the capacity of the oceans to absorb carbon.

• Melting of ice in North American glaciers is adding freshwater to the North Atlantic. This is reducing the salinity of the ocean and slowing the sinking. This means there is nowhere for warm waters to go and the North Atlantic drift is slowing.

• If changes like this occur to ocean circulation, they will impact the marine ecosystems and cause food insecurity, lead to less carbon absorption and potentially lead to faster global warming (example of positive feedback)

Tipping Point

• Cold, deep water in the North Atlantic forms part of the thermohaline circulation

• To keep the ‘conveyor belt’ of warm water heading from the tropics towards Britain, heavy, salty water must sink in the north

• Melting of Northern ice sheets releases significant quantities of freshwater into the ocean, which is lighter and less salty- thus blocking and slowing the conveyor belt

• As ice sheets melt, thermohaline circulation is susceptible to a critical tipping point.

Ocean Acidification

• The FAO estimates that fishing supports 500 million people, 90% living in developing countries

As a result of its role as a carbon sink, ocean acidification is increasing due to fossil fuel combustion, and risks crossing the critical threshold for the health of coral reefs and other marine ecosystems that provide vital ecosystem services

• Up until the early 19th century, the average ocean pH was 8.2 but this had fallen to 8.1 by 2015

• Coral reefs stop growing when the pH is less than 7.8, and need temperatures of 23-29°C to survive

• Coral reefs shelter 25% of marine species, protect shorelines, support fishing industries, provide income from tourism

The Greenhouse Effect

The Natural Greenhouse Effect

• The Sun emits solar radiation that reaches the Earth’s atmopshere, and is refracted by greenhouse gasses

• Some waves get refracted to outer space, and some down to Earth, warming the surface

• 69% is absorbed by the surface, especially oceans

• 31% is reflected back to the atmosphere, the greenhouse gasses trapping some of the outgoing waves and reflecting them back to Earth, effectivly trapping heat and creating a warming effect

The Enhanced Greenhouse Effect

• Humans contribute to more greenhouse gasses in the atmosphere through burning fossil fuels, deforestation, livestock etc.

• Greenhouse gases allow more solar radiation to pass through Earth's atmosphere, and lets less heat escapes into space

• Greenhouse gases in the atmosphere have increased 25% since 1750

Effects of the Enhanced Greenhouse Effect

CO2 concentration in the atmosphere has risen from 317 to 410 ppm (1960-2020)

• A rise in mean global temperature

• More precipitation and evaporation

• Sudden shifts in weather patterns

• More extreme weather events

• Nature of climate change varying from region to region - some reas getting warmer and drier, others wetter

Knock-on effects

• Sea level rise from melting ice sheets and glaciers, and thermal expansion as the oceans warm

• Decline in goods and services provided by ecosystems, decline in biodiversity, changes in distribution of species, marine organisms threatened by lower oxygen levels and ocean acidification, coral bleaching

• Increasing temperatures and evaporation rates causing more moisture to circulate around the hydrological cycle

Formation of Fossil Fuels

• Remains of plants and animals sank to the bottoms of oceans, rivers, lakes

• Subsiquently covered by silt and mud

• Remains continued to decay anaerobically and were compressed and heated under immense pressures, eventually forming coal, oil and natural gasses

Coal - plant decay

• Anthracite is the hardest coal; is has the most carbon and, hence, a higher energy content

• Bituminous coals are next in hardness and carbon content

• Soft coals such as lignite and brown coal are lower in carbon (25-35%) and energy potential; these are the major global source of energy supplies but emit more CO2 than hard coals

• Peat is the stage before coal, it is an important carbon and energy source

Oil and gas - animal decay

• Occur in porous rocks, migrating up through the crust until meeting caprocks

• Natural gas, such as methane, is made up of the fractions of oil molecules, so small they are in gas not liquid, and usually found with crude oil

• Other hydrocarbon deposits include oil shales, tar sands and gas hydrates

Energy Security

The ability of a country to ensure adequate, affordable and consistent supply of energy

Based on 4 key components

• Availability

• Accessibility

• Affordability

• Reliability

Energy security is vital to the functioning of a country:

• Powers most forms of transport

• Lights settlements

• Used by types of commercial agriculture

• Warms / cools homes

• Powers domestic appliances

• Vital to modern communications

• Drives most forms of manufacturing

Energy Mix

The combination of different energy sources available to meet a country’s total energy demand

Primary Energy

• Any form or energy found in nature that has not been subject to any conversion or transformation

• Can be renewable or non-renewable

Secondary Energy

• Refers to the more convenient forms of energy, such as electricity

• Derived from the transformation or conversion of primary energy sources

Most energy today is consumed in the form of electricity, the main primary energy sources used to generate electricity are:

• Non-renewable fossil fuels - coal, oil and natural gas

• Recyclable fuels - nuclear energy, biomass, general waste

• Renewable energies - water, wind, solar, geothermal, tidal

Consumption of energy

• Measured in per capita terms e.g. megawatt hours per person

• Measured in energy intensity, assessed by calculating the units of energy used per unit of GDP. The fewer the units of energy, the more efficiently a country is using its energy supply. In general, energy intensity values decrease with economic development

Changing Global Energy Mix

Fossil fuels still make up 86% of global energy mix

How the energy mix has changed:

1820 - 20 exajoules

• Mainly biofuels (amount of biofuels remains constant until it rises slightly in the latter half of the 20th century)

• Very small amount of coal.

1900 - 50 exajoules

• 30 coal, 20 biofuel

1920 - 60 exajoules

• Now some oil and tiny amounts of hydropower.

A rapid increase takes place from 1940.

1960 - 120 exajoules

• About 40 of which is oil.

• Small amounts of natural gas now being used.

1980 - 330 exajoules

• Increase in hydropower (about 10) and natural gas now at about 50 exajoules.

• Introduction of nuclear power.

2010 - 540 exajoules

• About 40 biofuels, 150 coal, 190 oil, 110 natural gas, 20 hydro and 20 nuclear.

All values to the nearest 10 exajoules

Factors affecting per capita energy consumption

• Technology

• Physical availability

• Cost

• Economic development

• Standard of living

Public perceptions

• Attitudes towards energy differ

• Many consumers are worried nuclear power poses safety risks and wind turbines are ugly

• Coal is withidely percieved at ‘dirty’

• Natural gas is seen as ‘clean’ in comparison

Climate

• Very high levels of consumption in North America, the Middle East and Australia partly reflect the widespread use of air-conditioning in summer, and heating in the winter in countries such as Canada

Environmental priorities

• For some, the energy policy will be one of taking the cheapest route to meeting the nation’s energy needs, regardless of environmental costs

• Others seek to increase their reliance on renewable sources of energy

Energy consumption UK vs Norway

UK

Physical Availability

• Until the 1970s, the UK depended heavily on domestic coal from North East England

• It was also among global leaders in nuclear technology from the 1950s - 70s, but lost momentum after the discovery of large reserves of the North Sea oil and gas, whose increased use after the 1970s greatly altered the UK's energy mix

Cost

• The North sea reserves became a secure alternative to dependency on middle eastern oil as prices there rose in the early 70s

• However North sea oil is expensive to extract, so if global prices fall (1997-98 and 2014-15) it becomes less viable

• Stocks of north sea oil and gas are also declining, which is forcing the UK to import more

Technology

• There are 150 years worth of coal reserves in the UK, but current techology and environmental policy make its extraction unrealistic and expensive

• The UK's last deep coal mine closed in 2015, although 80% of the UKs primary energy still came from fossil fuels

• The technology exists for clean coal (absorbing CO2) but coal has lost its political support

Political Conciderations

• The increasing reliance on imported energy sources affects the UK's energy security, and this has become a political issue. However, public concern has grown over new fracking and nuclear sites

• The privatisation of the UK's energy security industry in the 80's means that overseas companies e.g. EDF decide which energy sources are used to meet the energy demand. They buy primary energy on international markets

Economic Development

• GDP per capita US$41,200

• Energy use per capita 2725kg oil

• Average household energy costs £1300

Energy consumption UK vs Norway

Norway

Physical Availability

• Because Norway is mountainous, with steep valleys and plentiful rainfall, HEP is the natural energy choice

• Much of the oil and natural gas in Norway's territorial waters is exported - e.g. the UK

• Coal from Svalbard is also exported

Cost

• Norsk hydro runs over 600 HEP sites, which supply 97.5% of Norways renewable energy

• HEP costs are low once capital investment is complete, however the transfer of electricity from HEP production in remote regions to the urban population and isolated sediments is expensive

Technology

• Deepwater drilling technology enabled both Norway and the UK to develop north sea oil and gas extraction

Political Considerations

• HEP has been used since 1907 and the Norwegian water and energy directorate manages the nation's power supply

• The Norwegian goverment has an interventionist approach which prevents foreign energy companies from owning any primary energy source sites - waterfalls, mines, forests

• Royalties and taxes paid to the government from the sale of fossil fuels boosts the standard of living through government spending, but profits also go to a sovereign wealth fund to prepare for a future without fossil fuels and eco friendly projects

Economic Development

• GDP per capita US$61,500

• Energy use per capita 5854kg oil

• Average household energy costs £2400

India

Depends on coal for 66% of its energy needs

Just one day after the 2015 Paris Climate Conference agreed to reduce global CO2 emissions, India declared that it intended to double its coal output by 2020

• Accounts for 6% of global CO2 emissions

• 3rd largest emitter after China and USA

• Wants to reduce its dependency on imported oil and gas towards more use of domestic coal

New infrastructure, expanding middle class and 600 million new users of electricity leading to the development and demand for coal

• Child labour in India’s coalmines keeps cost of coal low and promotes economic growth, but leads to the suffering of children and keeping them out of education

Energy Players

TNCs

• Gazprom, ExxonMobil, PetroChina, Royal Dutch Shell

• Nearly half of the top 20 companies are state owned, and therfore under government control (reflecting the importance of energy in national security)

• Most are involved in a range of operations: exploring, extracting, transporting, refining and producing petrochemicals

OPEC (Organisation of the Petroleum Exporting Countries)

• 13 member countries that, between them, own around 2/3 of the world’s oil reserves

• Due to this, it is in a position to partly control the amount of oil entering the global market and influence the price

• OPEC has been accused for holding back production in order to drive up oil prices

Energy companies

• Companies that convert primary energy into electricity and then distribute it

• EDF and E.ON in the UK

• Most companies are involved in the distrobution of both gas and electricity

• They have conciderable influence in setting consumer prices and tariffs

Consumers

• Most influential consumers are transport, industry and domestic users

• Largerly passive players in fixing energy prices

Governments

• Guardians of national energy security and can influence the sourcing of energy for geopolitical reasons

Energy Pathways

The route taken by any form of energy from its source to its point of consumption

• Oil and gas is transported by tanker ships from the Middle East to Europe, Asia and North America and also by pipelines and road/rail freight - goes through chokepoints, and if they are blocked or threatened, even temporarily, energy prices can rise quickly (2021 Suez Canal obstruction UK gas prices increased 14%)

• Gas is mainly moved by pipelines, especially from Russia to Europe, but also by liquified gas (LNG) ship tankers from the Middle East

• Coal is mainly transported by bulk-carrier ship and rail. Its lower energy density and high weight make transport costs high

Russian gas to Europe

Energy pathways are a key aspect of energy security, but can be prone to disruption as conventional fossil fuels have to be moved long distances from sources to markets

• Russia is the second largerst producer of gas, most of its exports going to European countries

• Russian gas is delivered to Europe through 5 main pipelines, 3 of which cross Ukraine

• Ukraine in a position of strength as it could increase its charges for allowing Russian gas to pass through it

• Gas supplies were disrupted in 2006 and 2009 due to disputes between Russia and Ukraine

• European countries increasinly reply on imported LNG from Qatar due to the unreliabiliy of Russian gas

UK drive towards security

• Currently the UK has stopped all gas imports from Russia due to the Russia Ukraine conflict

• The UK still obtains most of its imported gas from Norway, though recently has substantially increased imports of gas from Qatar in order to offset the declining output from its North Sea gas fields

Unconventional Fossil Fuels

Despite the need to move the global energy budget towards renewable energy sources, a lot of exploration is going into the search for new oil and gas fields

Tar Sands

• A mixture of clay, sand, water and bitumen (a heavy, viscous oil)

• Have to be mined and injected with steam to make the tar less vicous so that it can be pumped out

• (Canada)

Oil Shale

• Oil-bearing rocks that are permeable enough to allow oil to be pumped out directly

• Either mined, or shale is ignited so that the light oil fractions can be pumped out

Shale Gas

• Natural gas that is trapped in fine-grained sedimentary rocks

• Fracking: pumping in water and chemicals froces out the gas

Deepwater Oil

• Oil and gas that are found well offshore and at conciderable oceanic depths

• Drilling takes place from oceans rigs, already underway in the Gulf of Mexico and off Brazil

Issues and Players:

Unconventional Fossil Fuels

• They are all fossil fuels, so their use will continue to threaten the carbon cycle and contribute to global warming

• Extraction is costly and requires a high input of complex technology, energy and water

• They all threaten environmental damage

Players in the harnessing of unconventional fossil fuels:

Exploration Companies

• Key role in dicovering and developing reserves

• Keen to see good financial return on their exploratory work and willing to take risks with the environment to achieve this

TNCs

• Anxious that their investments in conventional fossil fuels are threatened by competition from these unconventional sources

Governements

• Some will see domestic sources of these fuels as offering a higher level of energy security

• Other may wish to avoid any pollitical fallout led by environmental groups and affected communities

Environmental Groups

• Well organised and vocal in pointing out risks and potential damage to the environment

• Favour renewable energy sources

Affected Communities

• Divide between those supporting exploitation of the sources on the grounds of providing jobs and generating local income and those that see the peace and quiet of their home areas and environmental quality being threatened

Nuclear Energy

Recycleable as can be reprocessed and resued

• France gets 70% of it’s electricity from nuclear power

Downsides

• Safety and security risks (Chernobyl 1986 and Fukushima tsunami 2011)

• Disposal of high-level radioactive waste with incredibly long decay life

• The technology involved is complex and therfore is usually only an option for developed countries

• Public attitudes to nuclear are often hostile

• Although operational costs are low, costs and construction and decommissioning power stations are high

Biofuels

Biomass - organic matter used as a fuel

Biofuel

• Derived directly from organic matter, such as agricultural crops and forestry products, and various forms of commercial and domestic waste

• Primary biofuels include fuelwood, wood pellets and chips used in unprocessed form primarily for heating, cooking and electricity

• Secondary biofuels are derived from the processing of biomass and include liquid biofuels such as ethanol and biodiesel

In the UK the main biofuel crops are rapeseed oil and sugar beet, which are mostly converted to ethanol or biodiesel to be used as vehicle fuel

Brazil

• Since the 1970s brazil has taken steps to diversify its energy mix and improve energy security

• 90% of new passenger vehicles sold have flex-fuel engines that work using any combination of petrol and ethanol, leading to a significant reduction in CO2 emissions

• Large areas of central southern Brazil are now set aside for the cultivation of sugar cane (ethanol production) resulting in the displacement of cattle rearing

• The need to find replacement pastures has resulted in large-scale clearing of the Amazon rainforest, nullifing the reduction in CO2 emissions gained from the increasing use of ethanol

Radical Energy Technologies

Carbon Capture and Storage

• Invloved ‘capturing’ the CO2 released by the burning of fossil fuels and burying it deep underground

• Very expensive process due to the complex tecnology involved

• Uncertainty over whether the stored capture will stay trapped underground and now slowly leak to the surface and into the atmosphere

Hydrogen Fuel Cells

• Combine hydrogen and oxygen to produce electricity, heat and water

• They will produce electricity as long as hydrogen is supplied, never losing charge

• A promising technology for use as a source of heat and electricity for buildings and power source for electric vehicles

• Difficult to find a cheap and easy source of hydrogen

Amazon and UK forests

The Amazon rainforest acts as a giant climate regulator

• It pumps 20 billion tonnes of water into the atmosphere everyday

• The forest’s uniform humidity lowers atmospheric pressure, allowing moisture from the Atlantic to reach almost across the continent

• Since 1990 a cycle of extreme drought and flooding has been observed, droughts in 2005, 2010 and 2016 greatly degrading much of the forest already stressed by prolonged and large-scale deforestation

The diminishing health of the tropical rainforest means that

• It is declining as a carbon store

• Sequestering less CO2 from the atmosphere, thereby exacerbating the greenhouse effect

• Playing a diminishing role in the hydrological cycle

UK forests

• Forest cover has been reduced from 80% to 10% by the end of the 19th century

• Forestry Commission was set up in 1919 to remedy the country’s shortage of timber but planting fast-growing exotic confers

• Today there is much less emphasis on the commerical production of timber and more on environmental benifits of restoring a forest cover close to the origional

The Environmental Kuznets Curve

Converting grasslands into farming

The American Midwest

2007 to 2015 a biofuel ‘rush’ swept across American Midwest

Farmers were encouraged to grow corn, soy, canola and sugar cane as part of the US Environmental Protection Agency’s Renewable Fuel Standard Policy. This policy aimed to:

• Increase amount of ethanol used in petrol

• Boost economies of US rural states

• Reduce US dependency on overseas oil imports

• Reduce CO2 emissions from transport

Growth in production reflected growing global demand. By 2013 the price of corn has tripled, and a number of US States (e.g. North Dakota) cashed in:

• Grasslands traditionally used for cattle ranching were ploughed up - over 5.5 million hectares of natural grassland disappeared across US Midwest, matching rate of rainforest deforestation in Brazil, Malaysia and Indonesia

Impacts

• Initial removal releases CO2 from soils into atmosphere as annual ploughing enables soil bacteria to release CO2

• Biofuel crops are heavy consumer of water so need irrigation which has a significant impact on aquifers

• Cultivated soils are liable to erosion by runoff and wind

The Arctic

Plays an important role in global climate as its sea ice regulates evaporation and precipitation

• Temperatures have risen 2.5℃ since the 1970s, twice as fast as the global average

• Arctic sea ice has declined by 40% since 1978 - the Northwest Passage is now open to summer navigation

• Much melting of permafrost, deepening of the active layer

• Total ice area in Yukon, Canada shrank by 22% between 1958 and 2008

• Carbon uptake by terrestrial plants is increasing because of a lengthening growing season

• A loss of albedo (the fraction of light that a surface reflects) as the ice that once covered the land surface gives way to tundra and tundra gives way to taiga

• Sunlight that was previously reflected back into space is now being increasingly absorbed by the ever-darkening land surface - encouraging further global warming

• Disrupting and destroying the traditional ways of fishing and hunting Inuits of North America and the Sami reindeer herders of northern Eurasia

• Opening previously ice-bound wilderness areas to tourism

• Exploitation of Arctic oil and gas becoming more feasible

Future Uncertainties

• Will levels of GHG emissions continue to rise and how fast?

• Is there a limited capacity to the degree of concentration of GHG in the atmosphere?

• What is the resilience and capacities of other carbon sinks?

• The degree of climate change - how much warmer?

• Rate of population growth

• Nature and rate of economic growth - will it always be carbon based

• The harnessing of alternative energy sources

• The possible passing of tipping points

Adaption stratergies for a changed climate

Water conservation and management

• Fewer resources used, less groundwater abstraction

• Attitudinal change operates on a long term basis: use more grey water

• Efficiency and conservation cannot match increased demands for water

• Changing cultural habits of a large water footprint need promotion and enforcement by governments e.g. smart metres

Resilient agricultural systems

• Higher-tech, drought-tolerant species help resistance to climate change and increase in diseases

• Low-tech measures and better practices generate healthier soils and may help CO2 sequestration and water storage: selective irrigation, crop rotation, reduced ploughing, agroforestry

• More expensive technology, seeds and breeds unavailable due to poor subsidence farmers without aid

• High energy costs from indorr and intensive farming

• Genetic modification is still debated but increasingly used to create resistant strains e.g. rice and soya

• Growing food insecurity in many places adds pressure to find ‘quick fixes’

Land-use planning

• Soft management: land-use zoning, building restrictions in vulnerable floodplains and low-lying coasts

• Enforcing strict runoff controls and soakaways

• Abandoning high-risk areas and land-use resettling is often unfeasable as in megacities such as Dhaka, Bangladesh or Tokyo, Japan

• Needs strong governance, enforcement and compensation

Flood-risk management

• Harm management traditionally used: localised flood defences, river dredging (removal of sediments and debris from the bottom of rivers)

• Simple changes can reduce flood risk e.g. permeable tarmac

• Reduced deforestation and more afforastation upstream to absorb water and reduce downstream flood risk

• Debate over funding sources

• Landowners may demand compensation for afforestation kept for flooding

• Constant maintenance needed for hard management e.g. dredging

Solar radiation management

• Geoengineering invlolves plans to deriberately intervene in the climate system to counteract global warming

• Proposal to use orbiting satellites to reflect some inward radiation back to space

• Untried and untested

• Would reduce but not eliminate the worst effects of GHGs e.g. would not alter acidification

Mitigation and rebalancing the carbon cycle

UK

Legal Framework

• Since 2019 the UK has had a target of net zero emissions by 2050, with carbon budgets setting out the pathway to this goal

Energy Sector

• By 2024-5 coal will no longer be used to generate electricity

• Low-carbon electricity producers, like wind and solar, are guaranteed a minimum price for electricity to encourage investment (a subsidy)

Taxation

• Tax on petrol and diesel sales, and annual car tax linked to carbon emissions per km

Transport

• In 2030 it is planned to phase out sales on new petrol and diesel cars in favour of electric and hybrid vehicles

Efficiency

• Cars, homes and electrical appliances all have energy ratings which indicate their energy efficiency

Carbon Capture

• CCS has not yet fullfilled its promise but the UK government has invested in a number of small pilot schemes

2015 Paris Agreement

195 countries adopted the first universally legally binding global climate deal:

• Keep the rise in global temperature to less than 2℃

• Report on the implementation of individual national plans to reduce emissions

• Provide adaptation and initiative support for developing countries to reduce emissions