Please enable JavaScript.
Coggle requires JavaScript to display documents.
HOW DO THE CARBON AND WATER CYCLES CHANGE OVER TIME - Coggle Diagram
HOW DO THE CARBON AND WATER CYCLES CHANGE OVER TIME
Land use changes
Urbanisation
Artificial surfaces are impermeable, prevents infiltration and offers no storage
Built drainage systems means water quickly flows into rivers
Development of floodplains reduces storage, removal of vegetation reduces organic carbon and burning fossil fuels releases C02
Forestry
High interception in natural forest with spruce or confer trees
Intercepted rainfall evaporates off leaves, long lag times and low discharge from rivers due to high evaporation
Increased run off during clear felling as trees in the uk contain 170-200 tonnes of carbon per ha
Farming
Deforestation reduces carbon storage in soil and trees, ploughing and oxidation reduces soil carbon storage
Harvesting returns a small amount of organic matter back to soils and exposes soils to erosion
Crop irrigation diverts surface water from rivers to cultivate land then lost to evaporation
Crop sintercept less warmer than rainforests where heavy machinery compacts soils, surface runoff increases
Water extraction
Aquifers are permeable pourus water holding rocks and ground water is extracted from them. Ground water feels rivers through springs upper surface of saturation called the water table
Artesian basins are aquifers confined between two permeable layers is under artesian pressure. If tapped by a well the water flows to the surface under its own pressure. The potentiometric surface is determines by the water table on the edge of basins. E.g London is the centre of an artesian basin with the water trapped between two types of clay.
Rainwater enters outcrops on the edge of the basin then flows by gravity to the centre, important source of water to the capital but over exploitation can decrease the water table
Fossil fuels and carbon sequestration
In 2019, 84% of global energy consumption was coal oil and gas. Fossil fuel consumptions releases 10 billion tonnes of C02 per year
Sequestration of waste carbon
Carbon capture and storage
C02 is compressed and stored deep underground to be stored
Has the potentia to reduces emissions by 80-90% in the USA
CCS project is underway in north east Scotland and North Yorkshire with plans to capture 2 million tonnes per year and transport it to the North Sea
Feedback loops
Water cycle
Positive
Rising temperatures
Increased evaporation
Atmosphere holds more vapour
Greater cloud cover and absorption of long wave radiation
Negative
More water vapour and cloud cover
More reflection of solar radiation
Less radiation absorbed by atmosphere/oceans/biomass
Temperature drops.
Carbon cycle
Positive
Global warming
Faster decomposition
More C02 released
Greenhouse effect
Negative
Rising C02
Photosynthesis stimulated
Excess C02 extracted and stored in biosphere
Long term storage
Diurnal changes
Within 24 hours
Low temperature at night- low evaporation and transpiration. High temperature during the day- convectional precipitation
During the day C02 flows from the atmosphere to vegetation. At night the flux is reversed and photosynthesis stops and vegetation loses C02
Seasonal changes
Solar radiation peaks in summer (800w/m2) and falls in winter (150w/m2)
Evapotranspiration highest in summer with 80% of rainfall looser to evaporation in the driest parts of England
River flows lowers in late summer
Water availability drives seasonal changes in the tropics but temperature drives changes in high latitudes
Long term changes
Glacial cycles and inter-glacial cycles each lasting 100,000 years
During glacial periods, water is stored as ice and sea levels fall and ice sheets cover 1/3 of continental land mass. Tropics become drier and less evaporation slows the water cycle
Reduction in C02 in the atmosphere as excess C02 is stored in the deep ocean beceause of changes in ocean circulations. Tundras replace rainforests as carbon pool shrinks because soil is covered by ice. Less vegetation, lower temperature and low rain so slow decomposition