Planetary Boundaries Flashcards
What are planetary boundaries?
represent limits of earth system’s capacity to maintain stable environment; safe operating space for planet -> based on Earth’s biophysical processes of analysis
guidelines that show we need to change behavior
show that earth system trends act in a non-linear and unpredictable way
How are planetary boundaries determined in theory?
tipping points: when treshold is reached
treshold: internal features of systems defined by position along one or more control variables
regime shifts: abrupt and often irreversible changes in the structure and function of ecosystems or the earth system as a whole
resilience: ability of an ecosystem to recover from disturbances and capacity to absorb disturbances
tipping point boundaries & slow control boundaries
Determination CLimate Change
staying on safe side of freshwater, land, aerosol, nitrogen, ocean and stratospheric boundaries
parameters: atmospheric concentration of carbon dioxide -> 350/ m per volume;
radiative forcing -> 1 w/ m2 above preindustrial level
current climate models might underestimate climate change,
stability of large polar ice sheets,
some of earth’s subsystems move outside their Holocene state
Determination Biodiversity loss
parameter: rate of species loss -> 10/ m species per year
conversion of nature -> agriculture purposes, more wildfires
rate of loss that cannot continue without significantly eroding the resilience of major earth-system functioning
Determination NItrogen cycle interference
rate at which N2 is removed from the atmosphere and converted to reactive nitrogen for human use
-> 35 mt / year
Are we past planetary boundaries?
human activities are pushing earths system -> could lead to irreversible change
staying within pb is essential to maintain a stable + resilient earth system
there is still time to prevent further transgressions but this requires transformative changes in government, management and global cooperation
safe operating space is static
Main differences 2009 and 2015
2009: foundational framework (9 PB’s), quantitative thresholds, emphasizes individual boundaries, more theoretical foundational framework
2015: refined & expanded (sub-boundaries such as genetic and functional diversity, refined based on higher levels of understanding, emphasis on interconnectedness of boundaries, practical guidance for policymakers
