Geography Physical - Carbon Cycle

• Carbon Cycle


  The exchange of carbon between the atmosphere, terrestrial biosphere, oceans and sediments
• Carbon Stores


  • Atmosphere
  • Coal, Oil and Gas
  • Sedimentary Rocks
  • Surface and Deep Ocean
  • Plants and soil
• Carbon Stores


  Function as sources (adding to the atmosphere) and sinks (removing from the atmosphere)
• Carbon Fluxes


  Movements of carbon from one store to another, provide the motion in the carbon cycle
• Slow Carbon Cycle


  Carbon held in sediment on the floor of the oceans can be stored for an extremely long time
• Fast Carbon Cycle


  The terrestrial part of the carbon cycle involves photosynthesis, respiration and decomposition of plant matter
• Measuring Carbon


  The amount of carbon on Earth is colossal, so carbon is measured in a unit called Pentagrams (Pg)
• Geological Carbon Cycle


  Carbon that moves between rocks and minerals, seawater, and the atmosphere can create rock formations such as limestone and chalk
• Geological Carbon Cycle


  1. Acid rain dissolves rocks rich in carbon, causing chemical weathering and releasing bicarbonates

  2. Carbon sediments are transported to the oceans via rivers, then deposited

  3. Carbon in organic matter sinks to the ocean floor, building up layers of chalk and limestone

  4. Heating along subduction boundaries alters sedimentary rocks creating metamorphic rocks, releasing CO2 from rocks which are carbon rich

  5. Rocks containing carbon get subducted at boundaries and re-emerge in volcanic eruptions

  6. Terrestrial carbon is released through volcanic eruptions as CO2, this is called out-gassing
• Bio-geochemical Carbon Cycle


  Carbon cycling through the process of photosynthesis, respiration, decomposition and combustion. Carbon is stored in oil, coal and natural gas
• The amount of carbon released or stored is determined by biological and chemical processes</b>
• Living organisms are critical in maintaining the bio-geochemical carbon cycle because they control the balance between storage, release, transfer and absorption of carbon
• Carbon Sequestration


  The removal and storage of carbon from the atmosphere. It occurs through photosynthesis and is held in oceans, forests and soils. It helps regulate the planetary temperature balance
• Oceanic Sequestering


  Oceans are the Earth's largest carbon store, storing 50 times more than the atmosphere. Most is stored in marine algae, plants and coral, the rest in dissolved form
• Biological Pump


  The ocean's biologically driven sequestration of carbon from the atmosphere to the ocean interior and seafloor sediments. It cycles organic matter formed by phytoplankton during photosynthesis, and calcium carbonate formed into shells
• Thermohaline Circulation


  A giant ocean conveyor belt that keeps the carbonate pump working, moving carbon compounds to different parts of the ocean in downwelling and upwelling currents
• Terrestrial Sequestering

  Plants sequester carbon out of the atmosphere during photosynthesis. Soils are the biggest land carbon stores, holding dead organic matter
• Tropical Rainforest as Carbon Stores

  The Amazon Rainforest covers 5.3 million sq km and holds 17% of the global terrestrial vegetation carbon stock. If left untouched, it takes in more carbon dioxide than it puts back
• Natural Greenhouse Effect


  The Earth is kept warm by greenhouse gases trapping the sun's radiation. Without this, the average temperature would be -18°C instead of +15°C
• Enhanced Greenhouse Effect


  Since the industrial revolution, increased burning of fossil fuels has emitted extra greenhouse gases, making the atmosphere thicker and trapping more solar radiation, causing the Earth to warm
• Changing greenhouse gas concentrations is likely to alter temperature and precipitation patterns
• Carbon Regulation


  Oceanic and terrestrial photosynthesis plays an important role in regulating the composition of the atmosphere. Soil health is a key factor in creating more biomass to sequester carbon
• Fossil Fuel Implications


  Fossil fuel combustion is the number one threat to the global carbon cycle, changing the balance of both the carbon stores and fluxes
• Ecosystems will see a decline in the goods and services they provide, a decline in biodiversity, and rapid changes in species distributions. Marine organisms are threatened by lower oxygen levels and ocean acidification
• Increased temperatures and evaporation rates will cause more moisture to circulate in the hydrological cycle, with less winter snowfall and rainfall, and changes to river discharge patterns
• Climate change will cause a rise in mean global temperature, sudden shifts in weather patterns, and more extreme weather events like floods, storm surges and droughts
• Melting permafrost in the Arctic releases carbon dioxide and methane, increasing greenhouse gas concentrations and leading to further temperature rises and melting
• Energy Consumption and Demands

  The amount of energy consumed depends on lifestyle, climate, technology, availability and demand. Demand has risen due to increasing population, economic development and rising living standards
• There is a very close relationship between GDP per capita and energy consumption, as energy is necessary for countries to become economically successful
• Energy Security


  Access to reliable and affordable sources of energy. Key aspects are availability, accessibility, affordability and reliability
• Having energy security is fundamental for transportation, lighting, agriculture, domestic appliances, communication and manufacturing
• Energy Mix


  A combination of the various primary energy sources (fossil fuels, nuclear, renewables) used to meet energy needs in a given region. Most energy today is consumed as secondary electricity
• UK Energy Mix


  • Dependent on domestic coal, increasing use of North Sea oil and gas, concerns over fracking and nuclear, aims to broaden mix with more renewables and nuclear
• Norway Energy Mix


  • Huge oil and gas potential, 98% renewable electricity from hydropower, government restricts foreign ownership, profits go to wealth fund
• Energy Players


  • Transnational Corporations
  • Consumers
  • Organization of Petroleum Exporting Countries
  • Energy Companies
  • National Governments
• UK aims for future energy mix


  • Greater emphasis on renewable sources (particularly offshore wind)
  • Greater emphasis on nuclear energy (Hinkley Point C near Bristol)
• UK - Carbon dioxide levels have decreased from 11.5 tonnes in 1980 to 7.13 tonnes per capita in 2015
• Fossil Fuel Demand & Mismatch


  There is a mismatch between locations of conventional fossil fuel supply (oil, gas, coal) and regions where demand is the highest
• The growth of development around the world has meant global demand for energy is increasing
• Fossil fuels (oil, gas and coal) still make up 86% of the global energy mix