In News:

A new report from the Potsdam Institute for Climate Impact Research (PIK) indicates that the world's oceans are nearing critical acidity levels.

• Key Findings:
  • Nine Crucial Factors: The report identifies nine essential elements for sustaining life on Earth.
  • Exceeded Limits: Six of these factors have already surpassed safe limits due to human activities.
  • Ocean Acidification: This is poised to become the seventh boundary breached.
• Crossed Boundaries:
  • Factors Affected:
    • Climate change
    • Loss of natural species and habitats
    • Depletion of freshwater resources
    • Increase in pollutants, including plastics and agricultural chemicals
• Causes of Ocean Acidification:
  • Primarily driven by rising carbon dioxide (CO2) emissions from burning fossil fuels (oil, coal, gas).
• Implications of Acidification:
  • Damage to corals, shellfish, and phytoplankton, disrupting marine ecosystems.
  • Threats to food supplies for billions of people.
  • Reduced capacity of oceans to absorb CO2, exacerbating global warming.
• Ozone Layer Status:
  • Currently not close to being breached; showing recovery since the banning of harmful chemicals in 1987.
• Air Quality Concerns:
  • A ninth boundary related to particulate matter is near danger limits.
  • Improvements in air quality are noted, but industrializing nations still face pollution risks.
• Tipping Points:
  • Crossing these boundaries could lead to irreversible and catastrophic consequences for humanity and future generations.
  • All boundaries are interconnected; breaching one can destabilize the entire system.
• Opportunities for Solutions:
  • Addressing critical issues, such as limiting temperature rise to 1.5 degrees Celsius above pre-industrial levels, can have widespread benefits across multiple environmental challenges.

Planetary boundaries

• The planetary boundaries were introduced in 2009 to define the global environmental limits within which humans can safely live.
• Johan Rockström, former director of the Stockholm Resilience Centre, led a group of 28 renowned scientists to identify the nine processes that regulate the stability and resilience of the Earth system.
  • Climate Change: Greenhouse gas concentrations, primarily CO2, are the primary metric here. Exceeding the recommended levels risks amplifying global warming.
  • Ocean Acidification: Oceans absorb CO2, leading to decreased pH levels. This boundary measures the carbonate ion concentration, vital for marine life like corals.
  • Stratospheric Ozone Depletion: The ozone layer protects life from harmful ultraviolet radiation. This boundary emphasizes the ozone concentration in the stratosphere.
  • Nitrogen and Phosphorus Cycles: Excess nitrogen and phosphorus, often from fertilizers, can disrupt ecosystems. Here, the focus is on their flow into the environment.
  • Freshwater Use: Freshwater is vital for life. This boundary pinpoints the annual consumption of freshwater resources.
  • Land-System Change: As we modify landscapes, particularly through deforestation, we alter habitats and carbon storage capabilities. This threshold concerns the amount of forested land remaining.
  • Biodiversity Loss: Biodiversity underpins ecosystem resilience. This metric observes the extinction rate of species.
  • Atmospheric Aerosol Loading: Aerosols influence climate and human health. This boundary examines their density in the atmosphere.
  • Chemical Pollution: Synthetic chemicals can harm ecosystems and human health. This boundary reviews their concentration and spread.