What’s the news?

• The Earth, our only home, is facing a severe health crisis due to the unchecked activities of human beings. A recent study reveals that we have breached six out of nine planetary boundaries.

Central idea

• Human activities have pushed Earth’s blood pressure dangerously high, imperiling the planet’s well-being. A recent study titled Earth beyond six of nine planetary boundaries, conducted by a global team of 29 scientists from eight countries and published in Science Advances, reveals that we have transgressed six out of nine planetary boundaries, akin to the vital parameters of Earth’s health.

What are the planetary boundaries?

• The planetary boundaries are a framework developed in 2009 that defines the limits of humanity’s impact on Earth’s essential processes and systems.
• These boundaries serve as guardrails to ensure that human activities do not push the planet beyond a point where it can no longer maintain the conditions necessary to support modern civilizations.
• These boundaries help identify the environmental limits within which human societies can thrive without causing irreversible damage to the Earth’s ecosystems.

Nine planetary boundaries and their associated control variables

• Biosphere Integrity: This boundary relates to the health of ecosystems and the rate of species extinction.
• Climate Change: It involves the concentration of atmospheric CO2 and the change in radiative forcing, which measures the balance of energy from sunlight compared to thermal energy lost by the Earth.
• Novel Entities: This boundary focuses on human-made substances not naturally found in the environment, such as synthetic chemicals, plastics, and genetically modified organisms.
• Stratospheric Ozone Depletion: This boundary concerns the release of human-made chemicals that harm the ozone layer in the stratosphere.
• Freshwater Change: It examines human-induced impacts on both blue (in lakes and rivers) and green (available in soil for plants) water resources.
• Atmospheric Aerosol Loading: This boundary tracks various particles from human-made emissions that affect cloud formation and atmospheric circulation.
• Ocean Acidification: It addresses the long-term reduction in ocean pH due to the absorption of excess atmospheric CO2 by seawater.
• Land System Change: This boundary evaluates changes in land use, especially the conversion of natural landscapes to agriculture or urban areas.
• Biogeochemical Flow: It focuses on alterations in the natural flows and forms of nitrogen and phosphorus cycles, essential for plant growth.

Findings of the study regarding the state of planetary boundaries

• Breached Planetary Boundaries: Out of the nine planetary boundaries identified, six have been breached by human activities. These boundaries include climate change, biosphere integrity, freshwater change, land system change, biogeochemical flows, and novel entities.
• Remaining Within Constraints: Two planetary boundaries, namely atmospheric aerosol loading and ozone depletion, are reported to remain within acceptable constraints. However, the boundary related to ocean acidification is noted as being close to being breached.
• Concerns about Nitrogen and Phosphorus: The study emphasizes the issue of an overflow of nitrogen and phosphorus, which falls under the biogeochemical flow boundary. While these elements are essential for life, their excessive use as crop fertilizers is causing problems such as algal blooms and ocean dead zones, where oxygen levels in the water decrease significantly, posing a threat to marine ecosystems.
• Historical Violations: The biosphere integrity boundary was reportedly violated in the 19th century due to rapid land use changes that significantly impacted various species. Similarly, the freshwater boundary was breached in the 20th century, specifically between 1905 and 1929.
• Rising Levels of Novel Entities: The study raises concerns about the increasing levels of novel entities in the environment. These include synthetic chemicals like pesticides and plastics that have been released into the environment without adequate safety testing. The presence of these novel entities is seen as destabilizing and harmful to the Earth’s systems.
• Land System Change: The article highlights that land-use conversion and fires are contributing to rapid changes in forested areas. Notably, deforestation in the Amazon tropical forest has increased to the point of transgressing the planetary boundary.
• Climate Change: The analysis of climate change indicates that both atmospheric CO2 concentration and radiative forcing are steadily increasing. For instance, the concentration of CO2 currently stands at 417 parts per million (ppm), significantly higher than the pre-Industrial Revolution level of 280 ppm. The safe boundary limit for CO2 concentration is noted as 350 ppm, which was breached in the 1980s.

Can Earth’s health still recover?

• Unlike tipping points, which can lead to large and often irreversible changes in the climate system, planetary boundaries are described as being more flexible.
• This means that breaches of these boundaries do not necessarily result in irreversible damage, and corrective actions can bring the Earth back within a safe operating space.
• For example, the stratospheric ozone depletion boundary is improving. This improvement is attributed to the combined international efforts initiated by the Montreal Protocol in 1987. The successful coordination to address ozone depletion serves as a positive precedent for addressing other breached boundaries.

Two Important Actions for Recovery

• Ending Fossil Fuel Burning: Curtailing or ending the burning of fossil fuels, which is a major contributor to climate change, is seen as essential. This action would help address the breach of the climate change boundary.
• Ending Destructive Farming: Implementing sustainable farming practices and reducing the negative impacts of land-use changes, including deforestation, can help restore ecosystems and address breaches related to land system change and biosphere integrity.

Conclusion

• We are at a critical juncture where concerted global efforts can still heal our planet. We must prioritize sustainability, conservation, and responsible resource management to ensure that future generations inherit a habitable Earth. The time to act is now, for Earth’s blood pressure has risen dangerously high, and the consequences of inaction could be catastrophic.

Also read:

Sustainable agriculture, climate change and nutrition: a complex challenge

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