Future risks

• RCP 8.5 - emissions continue at current rates. Not likely to exceed 4 degrees warming. Serious business impacts
• RCP 6.0 - some mitigation. Emissions rise until 2080 and then fall. Likely exceeds 2 degrees
• RCP 4.5 = strong mitigation. Emissions peak at 2040 and reach current levels in 2100. Most likely won't exceed 2 degrees warming
• RCP 2.6 = aggressive mitigation. Emissions halved by 2050. Won't exceed 2 degrees warming. Serious business impacts
• Uncertainty in future:

  • Carbon sinks - ocean and forest lead times reacting to changes in greenhouse gases take decades
• Uncertainty in future:

  • Forest increasing in developed countries, but generally decreasing in developing countries (contrast with Africa green wall)
• Uncertainty in future:

  • Financial crisis created uncertainty as it is related to emissions. Policy decision effecting economy. Kuznet curve
• Uncertainty in future:

  • Energy consumption grew by 2% between 2008 and 2014, yet renewables = 2/3 of new electricity production in 2015
• Uncertainty in future:

  • Affluence in developing economies = increased purchasing power. 1b new consumers expected come 2050
• Feedback mechanisms:

  • Peatlands - stores large amount of carbon due to slow breakdown as it's waterlogged. Warming = decreased water tables = increased decomposition
• Feedback mechanisms:

  • Peatlands - 4 degrees of warming = 40% loss of soil organic carbon
• Feedback mechanisms:

  • Permafrost - melting releases CO2 and Methane. Positive feedbacl
• Feedback mechanisms:

  • Forest die back - when rainforests subjected to droughts and trees die back
• Feedback mechanisms:

  • Forest die back - increased die back = less moisture recycled via transpiration
• Feedback mechanisms:

  • Thermohaline circulation - melting of ice sheets = freshwater in ocean = less salty and dense water
  • Salty water stops warm water going north so warm water will go to tropics