3.1.1.4 water + carbon + climate + interrelationships

• Natural Rainforest Water Cycle:

  • Precipitation falls - 75% intercepted by trees and through stem flow
  • 35% is used by plants and through transpiration returns to the atmosphere
  • 25% evaporates almost immediately and returns to the atmosphere
• Deforested Rainforest Water Cycle:

  • Precipitation falls
  • most reaches the ground immediately with little vegetation to intercept the rainfall, leading to high surface runoff, with higher flooding risk
  • Less evapotranspiration, so the atmosphere is less humid and rainfall decreases
• Deforested Rainforest Carbon Cycle:

  • Lack of trees so photosynthesis is reduced
  • Fires to clear land leads to CO2 being released into the atmosphere.
  • Forests become a carbon source instead of a carbon sink
  • Lack of life until new plants grow
  • Low rates of decomposition occurs in this environment
• Global Intervention - Paris Climate Deal (COP21):

  • Aim to limit global temperatures to 2°C above pre-industrial levels
  • Support for developing countries
  • Public interaction and awareness scheme
  • Meet every 5 years to review and improve goals
• Regional Intervention - EU 20-20-20:

  • 20% reduction in GHG emissions and commitment to 20% of energy coming from renewable sources and 20% increase in energy efficiency by 2020
  • EU has suggested it will increase its emissions reduction to 30% if major GHG producing countries also improve their targets
• National Intervention - Climate Change Act 2008 UK:

  • Legally binding target for the UK to reduce GHG emissions by 80% of 1990 levels by 2050 with a target of 26% by 2020 which has recently increased to 34%
  • Created national carbon budgets and the Independent Committee on Climate Change to help the government and report on progress that is being made