Earth System Boundaries (ESBs)

Current Affairs, Environment & Ecology

Why in News:

Earth’s Health at Risk in Seven out of Eight Key Measures, Warn Scientists

Important Points:

  • A groundbreaking analysis by the Earth Commission group of scientists reveals that human activity has pushed the planet into a perilous state concerning seven out of eight newly established indicators of planetary safety and justice.
  • The report goes beyond the well-known issue of climate disruption and highlights alarming evidence of growing crises in water availability, nutrient loading, ecosystem maintenance, and aerosol pollution, all of which pose threats to life-support systems and exacerbate social inequality.
  • Published in Nature, this study represents the most ambitious interdisciplinary science assessment of the entire people-planet system, combining vital signs of planetary health with indicators of human welfare.

Earth Commission:

  • The Earth Commission, established by leading research institutions globally, aims for this analysis to serve as the scientific foundation for the next generation of sustainability targets and practices, expanding beyond climate change to address other indices and environmental justice.
  • The hope is that cities and businesses will adopt these targets to gauge the impact of their activities.
  • The study sets “safe and just” benchmarks for the planet, analogous to vital signs for the human body, focusing on indicators such as water flow, phosphorus use, and land conversion.
  • The boundaries are based on a synthesis of previous studies by universities and UN science groups, including the Intergovernmental Panel on Climate Change and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

Safe and Just:

  • The Earth Commission emphasizes a “safe and just” climate target of 1°C to protect people from extreme heat, droughts, and floods. Achieving this target necessitates a substantial effort to remove carbon dioxide from the atmosphere, alongside ecosystem preservation.
  • To meet the climate target, it is essential for 50 to 60% of the world to consist of predominantly natural ecosystems, but the reality is that only 45 to 50% of the planet currently has intact ecosystems.
  • Altered areas, like farms and cities, should dedicate at least 20 to 25% of their land to semi-natural habitats to maintain ecosystem services, yet about two-thirds of such areas fail to meet this goal.
  • Addressing aerosol pollution is crucial, both globally and locally. At the global level, the focus is on balancing aerosol concentrations between the northern and southern hemispheres to avoid disrupting weather patterns. Locally, a boundary of 15 micrograms per cubic meter mean annual exposure to PM2.5 is established, following the World Health Organization’s guidelines, given its harmful effects on health, disproportionately affecting vulnerable communities.

Safe Boundary:

  • For surface water, the safe boundary indicates that no more than 20% of the flow of rivers and streams should be obstructed in any catchment area, as this negatively impacts water quality and freshwater species habitat. However, this boundary has already been surpassed on a third of the world’s land due to hydroelectric dams, drainage systems, and construction.
  • Similarly, groundwater systems face challenges, as 47% of the world’s river basins are depleting rapidly, particularly in densely populated areas like Mexico City and intensive agricultural regions like the North China Plain.
  • Nutrients also raise concerns, as farmers in wealthier nations overspray nitrogen and phosphorus, leading to harmful runoff into water systems. The report stresses the importance of global equity, with poorer nations needing more fertilizers while wealthier nations must reduce the surplus.
  • Achieving a balanced “safe and just boundary” requires a global surplus of 61 million tonnes of nitrogen and approximately 6 million tonnes of phosphorus.

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