Fragile Environments

Fragile Environments

1. Desertification

   • Benefits of Agroforestry
     • Increased productivity/food security and improved nutrition for rural communities
     • Increased production of wood and other tree products, thus reducing poverty
     • Increased production of fuel wood
     • Counters global warming as tree growth sequences carbon
   • The consequences of deserterfication: Climate change/global warming: The worlds forests are major carbon sinks so clearing forests releases carbon into the atmosphere either through burning or decomposition
   • Causes of soil erosion
     • Naturally occurring droughts: semi-arris latitudes generally rely on seasonal rains (like monsoons) and these are unreliable and can fail.

2. Deforestation

   • Results in soil infertility because:- The bulk of the nutrients are removed when the tree cover is burnt/removed, Any remaining nutrients in the litter layer are lost rapidly because rates of decomposition and run off are high, because any remaining nutrients in the soil are lost rapidly because of high levels of soil erosion of the exposed soil and high levels of leaching
   • Solutions to the problem: The key here is to manage forests in a sustainable fashion. This is being attempted at a range of scales
     • Global scale
       • The international agreements and programs have been initiated: The international tropical timber agreement in 2006 in theory, at least, only allows trade in timber from certified, sustainable sources from government regulated felling programmes
       • The UN programme emissions from deforestation and forest degradation in 2008. Now has over 60 signatory countries but progress has been poor.
     • National Scale
       • Biosphere reserves, national parks, etc:any permitted activities are generally limited to scientific research and occupation by indigos people
       • Controlled forestry: governments restrict logging licences/permits and encourage selective logging (even heli-logging) re-planting schemes.
   • Causes
     • Agriculture is responsible for 32% in forests
     • Commercial logging is responsible for 26%
     • Strip mining
     • HEP: Governments in LICs seek to further develop by constructing HEP schemes flooding large areas

3. Climate Change

   • Natural reasons for climate change
     • Variations in solar output: There is an 11 year cycle in snapshot activity, marking variations in solar flares and output of solar radiation. (more snapshots =less output
     • Volcanic eruptions: In the long term, eruptions are the single biggest source of carbon dioxide and, therefore provide our natural greenhouse effect.
   • Solutions
     • `The UN Climate change conference
     • Carbon emissions trading
     • Reducing incoming solar radiation
     • The UN climate change conference in Paris

4. Definitions

   • Sustainability: The exploitation of the worlds resources to meet the needs of the current generation without compromising the ability of future generations to meet their own needs.
     • World population growth hit approx 6 billion in 2000 projected 11.5 billion in 2100
   • Ecological Footprint: A tool used to access whatever a person or a society is living sustainably, it is the area of land required to enable a person to live at their current standard.
   • Leaching: The downward movement of nutrients in the soil as they are dissolved from the top soil and deposition in the subsoil
   • Greenhouse effect: Greenhouse effect is when incoming short wave UV radiation passes through the atmosphere but ongoing long wave radiation is absorbed by gases like Co2, Methane, C
   • Deforestation: Is the removal of a areas tree cover (by clear felling, burning, etc.) at a faster rate than it is replaced by either regeneration or re-planting
   • Soil erosion: The removal of topsoil by the wind and flowing water