Carbon cycle and Energy Security

Carbon cycle and Energy Security

1. How are the carbon and water cycles linked to the global climate system?

   • Biological carbon cycles and the water cycle are threatened by human activity.
     • ocean acidification: ph is decreasing so is more acidic. It could be 7.8 by 2100, which will dissolve coral skeletons and disintegrate coral reefs
       • ocean health is important because all countries eat or sell fish, 520 mil of the poorest people on earth depend on fisheries for food and income. Mangroves protect coastlines. Coral reefs provide tourism income e.g 1 million people visit the Maldives per year.
       • Affects the oceans role as a carbon sink because it cannot hold as much carbon due to algae in coral not being there to absorb it.
     • Conversion of grasslands: farmers are encouraged to grow corn, soya etc which use carbon based fertilisers and pesticides in production, so indirectly add to CO2 emissions. Initial clearing releases Co2 and annual ploughing lets soil bacteria release Co2.
     • Deforestation: since the 1950's tropical rainforests cleared rapidly which has major impact on size of terrestrial carbon store. less biomass to store carbon, as rainforests disappear, CO2 emissions increase. Soil is more vulnerable to erosion.
     • Arctic amplification: the arctic region warming twice as fast as any other region. it is more vulnerable because it stores more than any other region.
       • Melting permafrost is a positive feedback loop. it releases CO2 and CH4 which increases concentration of ghg in atmosphere, leading to increased global temps and further melting.
       • Affects climate ecosystems: Tundra - sea ice melting in summer, reduced snow cover and a reduction in permafrost. Shrubs previously unable to survive have now started to establish, and animals such as the red fox in Alaska now competing with the Arctic fox for territory. Warmer temps increase decomposition which releases carbon and nutrients. Nutrients encourage plant growth and the removal of carbon from the atmosphere through photosynthesis
       • Impacts the hydrological cycle: by 2100 the Eastern Alps will be ice free. Precipitation in the form of snow will diminish. River discharge patterns will change. there will be drought in summer and flood in winter.
   • Kuznetsk curve model-the relationship between a country's economic growth and environmental degradation. Tipping point of where a country moves from exploitation to protection. E.g Indonesia's forest moratorium aimed at reducing deforestation.

2. what are the consequences for people and the environment of our increasing demand for energy?

   • Non-renewable= finite. exploitation of these sources will lead to their exhaustion e.g coal, gas
     • Renewable: Solar, wind, wave power are continuous flows of nature so are constantly reused.
       • Recyclable energy: reprocessed uranium and plutonium from nuclear plants.
       • The move to renewables is not straight forward because many renewable installations e.g wind turbines require industrial processes that use energy that indirectly add to CO2 emissions. Biomass requires a fuel to kick start burning. some biomass fuels therefore produce 150-400% more CO2 than coal.
   • Biofuels= general name for fuels made from organic material such as plant material and animal waste.
     • Brazil 2003 use of bioethanol reduced CO2 emissions by 350m tonnes. Many countries followed in their footsteps.
       • Pros: biodegradable, recyclable, low emission, don't require specialist machinery to grow
       • Cons: Takes land from food procution, clearing forests releases CO2, requires pesticides and fertilisers which use CO2 in their production so is not carbon neutral.