Carbon

• fluxes of the carbon cycle include photosynthesis, respiration, combustion, decomposition, diffusion, sedimentation, wethering and erosion, metamorphosis, volcanic outgassing
• oceans store 50 times more carbon than the atmosphere
• the colder the water the more CO2 is absorbed so concentration of CO2 around the world is different
• CO2 Concentration is 10% higher in deep ocean compared with the surface of the ocean
• warm tropical waters release CO2 to the atmsophere but cold latritude oceans absorb CO2 from the atmosphere
• The physical pump consiosts of oceanic circulation which provides a constant new source of water on the surface whilst transferring surface water into the deep ocean
• The biological pump is phytoplankton which photosynthesise and take in carbon and turn it into organic matter. CO2 is also released through respiration. Plankton also sequester CO2, turning carbon into their hard outer shells and inner skeletons
• Thermohaline Circulation is an ocean current that produces both vertical and horizontal circulation of cold and warm water around the worlds oceans
• Rate of circulation in the thermohaline circulation is slow- takes around 1000 years for any cubic metre of water to travel round the entire system. Warm surface water is depleted of CO2 and nutrients therefore the foundation of the plants food chain depends on cool nutrient rich water which supports algae to grow
• The path of the Thermohalin circulation = The main current begins in the polar ocerans where the water is very cold, surrounding seawater sinks due to its higher density. The current is recharged as it passes Antarctica by extra cold, salty , dense water. Division of the main current- northward into the indian ocean and into the western pacific. These two branches warm and rise as they travelk northward then loop back southward and westward. The now warmed surface waters continue circulating around the globe. On their eventual retun to the North Atlantic they cool and the cycle begins again
• Rate of absorbtion of CO2 dependent on ocean temperatures. As ocean temperatures increase, the oceans will absorb less CO2- accelerating climate change and leading to further ocean warming- positive feedback mechanism
• Tropical areas such as Brazil and Indonesia have seen a decrease in carbon stocks of around 5 gigatons of carbon in the last 25 years
• Brazil has the most carbon stored on land and the most extensive deforested area
• China has the largest amount of afforested area
• Net Primary Productivitry refers to the amount of carbon absorbed by forests
• soils store between 20-30% ofd the worlds carbon
• Most long term process is the formation of humus, 60% of it contains carbon
• factors affecting soil capacity to storte organic carbon include climate, soil type, use of soils
• since the 1970s global concentrations of greenhouse gases have increased by more than 25%
• since the 1980s, 75% of carbon emissions haver come from burning fossil fuels
• Human activities have led to more carbon being released into the atmsophere than being absorbed
• land use change impacts short term stores in the carbon cycle such as soil and the atmosphere. E.g farming practices in trhe Amazon, 70% of deforestation is for cattle ranching- producing more methane- further contribuiting to climate change
• Deforestation accounts for 20% of all global greenhouse emissions. Cycle is interrupted where land is used for other pruposes- turning the land into a carbon source rather than a carbon sink
• Urbanisation is the procesws of replacing sountryside with buldings and other similar infrastructure. It affects global and local carbon cycles, by replacing vegetation and covering soils. Urban areas occupy 2% of the world land mass but accounts for 97% of all human caused global CO2 emissions- cement important building material but releases CO2 during production.
• combustion of fossil fuels results in CO2, sulpher and particulates being released into the atmosphere . If combustion occurs in a hot engine then NO2 will also be released
• Human activities contributing to increased carbon includes land use change, fetilisers, deforestation, urbanisation, combustion of fossil fuels
• The amount of carbon released into the atmosphere is meausred in gigatonnes or petagrams. It is estimated burning fossil fuels has added more than 180 Gt of carbon to the atmosphere
• The arctic region is warming twice as fast as the global average
• The two biomes most at risk are the Arctic and the coral ecosystems
• Implications of the enhanced greenhouse effect includes impacts on the hydrological cycle. Increased rates of evaporation could lead to more moisture being held in the atmsophere rather than in the ocean. Increase in surface permafrost temperatures. Less sea ice and glacier storage. Change in capacity of terrestrial ecosystems and change in river discharge - increased risk of flooding in winter and droughts in the summer
• maximum energy security refers to the uninterupted availability of energy sources at an affordable price
• long term energy security deals with timel;y ionvestments to supply in energy sources that will match econopmic developments and environmental needs
• short term energy security focuses on the ability of the energy system to react promptly to sudden change in the balance between energy demand and energy supply
• Aspects of energy supply include: availability, accessability, affordability and reliability
• The countries that are most energy secure are those who can meet their energy demand using supply from within their boundaries
• A good energy supply is consistent and secure and can be relied upon year rouynd. There is unlikely to be any geopolitical problems and there is little risk from changing climatic conditions or natural hazards . A good quality energy supply also involves different sources whioch contribute to energy mix
• Energy intensity decreases with development as energy is used more efficiently and so cost per unit of GDP reduces
• Coal accounts for 27% of global energy production. Usage is decreasing as China moves away from coal to less poluting energy sources
• Oil accounts for 32% of global energy production
• Tidal renewable enrgy is very expensive and so far unsuccessful. The swansea bay scheme was abandoned due to the potential costs but one successful project may lead to a multiplier effect