Linked carbon and water

• Human activities cause change in water and carbon stores

  The human impact on the water cycle is most evident in rivers and aquifers

  -rising demand for water for irrigation, agriculture and public supply, especially in arid and semi dry environments has created shortages
• interlinkages- atmosphere

  -atmospheric co2 has a greenhouse effect

  -co2 plays a vital role in photosynthesis by terrestrial plants and phytoplankton

  -plants which are important carbon stores, extract water from the soil and transpire it as part of the water cycle

  -water is evaporated from the oceans to the atmosphere and co2 is exchanged between the two stores
• interlinkages- oceans

  -ocean acidity increases when exchanges of co2 are not in balance
• interlinkages- vegetation and soil

  -water availability influences rates of photosynthesis, inputs of organic litter to soils and transpiration

  -the water-storage capacity of soils increase with organic content

  -temperatures and rainfall affect decomposition rates and the release of co2 in to the the atmosphere
• effects of human activities on water stores

  -deforestation reduces evapotranspiration and therefore precipitation ,increase surface run and decrease through flow
• human activity impacts on carbon stores

  -the exploitation of coal, oil and natural gas has removed billions of of tonnes of carbon from geological stores

  -land use change (deforestation) transfers 1 billion tonnes of carbon to he atmosphere annually
• human active impact on carbon and water stores

  -acidification of the oceans threatens this vital biological carbon store which is being degraded by erosion caused by deforestation and agricultural mismanagement

  -carbon stores in wetlands, drained for cultivation and urban development have also been depleted as they dry out and are oxidised
• impact of long term climate change on the water cycle

  -global warming has increased evaporation and therefore the amount of water in the atmosphere

  -meanwhile increased precipitation will result in higher run off in the water cycle and greater flood risks

  -water vapour is also a source of energy into the atmosphere, releasing latent heat on condensation, with more energy there will be more extreme weather events

  -melting of permafrost and the water storage in the crysphere shrink, as water is transferred to the oceans and atmosphere
• the long term impact of climate change on the carbon cycle

  -higher global temperatures will increase rates of decomposition and accelerate transfers of carbon from the biosphere and soil to the atmosphere

  -carbon frozen in the permafrost of the tundra is being released as temperatures rise above freezing and allow oxidation and decomposition of vast peat stores

  -meanwhile acidification of the oceans through the absorption of excess co2 from the atmosphere
• management strategies to protect the carbon cycle- afforestation 


  -planting trees in deforested areas

  -because trees are carbon sinks it can help reduce atmospheric co2 levels in the long term to help climate change

  -in china a government sponsored afforestation project began in 1978, it aims to afforestation 400,000km

  however the project will also help to combat desertification and land degradation
• management strategies to protect carbon store- agricultural practices

  -unsustainable agricultural practices such as overcultivation and overgrazing can lead to soil erosion and the release of large quantities of carbon to the atmosphere
• Management strategies to protect the water cycle- water allocation

  -In countries of water scarcity, governments have made the decision of allocating water sources

  -wastage of water occurs through evaporation and seepage through ineffienct water management

  -improved management techniques which minimise water losses o evaporation include mulching, zero soil disturbance and drip irrigation

  -better water harvesting with storage ponds and resoivoira povides farmers with extra water resources, recovery and recycling of waste water from agriculture
• management strategies to protect the global water cycle- drainage basin planning

  -specific targets for drainage basin planning includes run-off, surface water storage and groundwater, rapid-run off is controlled by reforestation programmes in upland catchments, reducing artificial drainage and extending permeable surfaces

  -surface water storage is improved by conserving and restoring wetlands, including temporary storage on floodplains