Planetary Boundaries

Planetary Boundaries

1. Definition: a boundary is a human determined value of the control variable set at a "safe" distance from a dangerous level. It aims to develop a safe operating space for human development based off the resilience of the Earth System

   • INDUSTRIAL REVOLUTION: Humans began investing in the nature environment rather than exploiting it
   • ANTROPOCENE: new epoch where humans constitute the dominant driver of change to the Earth's System

2. Catastrophic Nature of Transgressing Boundaries

   • Risk of triggering non-linear and abrupt environmental change
     • EXAMPLE: Biodiversity Loss can increase aquatic ecosystem vulnerability to climate and ocean acidity changes
       • Plankton and Coral Reefs acting as Carbon sinks
     • EXAMPLE: AMAZON TO TIBET. Deforestation of vegetation in the Amazon may disrupt the precipitation feedback loop and change the surface energy balance. This would weaken the deep convection and by driving the ITCZ northwards would influence the Jet Stream and precipitation in Tibet.
       • TIBET TO CHINA'S FLOODS.The climate chaneg in Tibet directly affects Asia's Water Resources, Glacier melt would increase short term flooding and place over 250 million poplin China at risk (Cruz et al, 2007)
   • All PB are interdependent: a shift in one boundary may cause another to be transgressed
     • Feedbacks can increaser trigger the likelihood of crossing thresholds in other boundaries
   • THRESHOLDS: intrinsic features of systems defined by a position along one or more control variables
     • EXAMPLE: Temperature and Ice-Albedo feedback in the case of Sea Ice

3. 3 branches of Scientific Enquiry

   • ONE: Scale of human action in relation to the capacity of the Earth to sustain it
     • TWO: Understanding the essential Earth System process (Human Action)
       • THREE: Framework of Resilience linked to complex dynamics and the self regulation of systems
   • Acccounting for the PRECAUTIONARY PRINCIPLE
   • Accounting for LIMITS TO GROWTH Approach

4. CLIMATE CHANGE

5. CHANGES IN BIOSPHERE INTEGRITY (BIODIVERISTY LOSS)

6. STRATOSPHERIC OZONE DEPLETION

7. OCEAN ACIDIFCATION

8. BIOGEOCHEMICAL FLOWS (N2 & P)

9. LAND SYSTEM CHANGE

10. FRESHWATER USE

11. NOVEL ENTITIES

12. ATMOSPHERIC AEROSOL OFF LOADING