planetary boundaries

• holocene


  Geological period the world has been in for the last 10 000 years. Temperatures were very stable - average temperature varied by only 1 degrees. Period of stability
• Anthropocene


  The period where humans are the primary drivers of change. Half of the land is farmlands and 1/2 of the Ocean has been fished.
• 1. Climate Change CO2, energy balance between earth and space


  in zone of uncertainty (yellow)

  • change in ice - If antarctica melts sea levels would rise by 50m every year. Antarctica is a permanent ice cap that reflects a lot of the suns light, if it melts global warming will increase by even more - causes a domino effect
  • Green house gases - CO2 boundary was crossed at 350ppm at 550ppm we enter high risk zone. We need to have a fossil free economy by 2050
• 2. Biosphere integrity

  High risk zone

  • 1 million out of 8 million species are threatened (heading towards extinction)
  • 30 % of birds are wild, only 4% of mammals
  • 70% of crops rely on pollination from insects by reducing biodiversity and killing these insects we harm the production of crops
  • Should be aiming for zero loss of land
• 3. Land use change

  uncertainty

  • land configuration (rain forests, savannahs, grasslands) are habitats which are changing
  • A large portion of the Amazon is being cleared for farming - data shows it is drying out, the dry season is 6 days longer
  • Savannization - lush rain forests gives way to an open landscape, the degraded forest could effect up to 60% of the Amazon
  • 40% of all trees have been cut down the Amazon has the potential to release 200 billion tons in the next 20 years
• 4. Fresh water changes

  safe zone
• 5. Ocean acidification


  still in safe zone but pushing towards danger zone

  • CO2 in ocean makes it more acidic - it creates carbonic acid, over a few years the ocean become 26% more acidic
  • Acid reacts with Bicarbonate ions and breaks them down. Sime things have bicarbonate ions in their shells or they need it to grow
  • can and has caused a mass extinction
• 6. Biochemical flow


  deep in the danger zone

  • Nitrogen and Phosphorus are impacted by fertilizers - it washes of fields and into rivers
  • causes eutrophication where algae blooms and as it decomposes O2 is used and the chemical composition of the water changes which leads to more phosphorus (positive feed back loop)
  • Dead zones on Ocean cause by nitrogen and phosphorus cover tens of thousand KM2
• 7. Novel entities

  not yet quantified

  • Human made pollutants - microplastics, nuclear waste, things humans have created and we don't yet know the long term consequences of them
• 8. Aerosol pollution


  not yet quantified

  • 75% comes from fossil fuel combustion, this causes global dimming, which cuts out sunlight and causes a cooling of the Earth so we can't see the full affects of global warming, we only feel 60% of the full effect of gloabl warming
• 9. Ozone depletion

  safe zone

  • the ozone intercepts harmful UV radiation that can cause cancer
  • a hole was discovered and countries banned the chemicals that caused it and the hole shrunk
• effects of crossing boundaries

  • collapse of coral reefs - when water is warm corals cook and die, marine heatwaves shrink the gap between coral bleaching events so there isn't time to recover
  • Forest fires: 50 million acres of land was lost in Australia in 2020, 3 billion animals were killed and displaced
  • Covid 19: Because some boundaries have been crossed it created the perfect conditions for a disease to spread
• Transformations

  things we must aim for to save the planet;

  • lower temperature and no emissions: if we bend the emissions curve and phase out fossil fuels we will come back to safe zone in many boundaries
  • draw down carbon: plant more trees to offset carbon, trees prevent erosion. no trees means less rain and more drought so trees help food production
  • Being conscious about food: more plant based, less red meat.,
  • reduce waste: use of resources can be infinite and it brings us closer to the safe zone in all boundaries