Earth beyond six of nine planetary boundaries

Area of Science:

• Earth system science
• Environmental science
• Global sustainability

Background:

• The planetary boundaries framework assesses the safe operating space for humanity.
• Previous assessments identified several transgressed boundaries, indicating increasing environmental stress.

Purpose of the Study:

• To update the planetary boundaries framework assessment.
• To evaluate the current state of Earth system boundaries and their implications for human well-being.

Main Methods:

• Analysis of Earth system data against established planetary boundary levels.
• Introduction of human appropriation of net primary production as a control variable for biosphere integrity.
• Earth system modeling to explore boundary transgression interactions.

Main Results:

• Six of nine planetary boundaries are now transgressed, indicating Earth is outside the safe operating space.
• Ocean acidification is nearing its boundary, and aerosol loading regionally exceeds its limit.
• Stratospheric ozone shows slight recovery, but transgression levels for other boundaries have increased.

Conclusions:

• Humanity is operating outside the safe planetary boundaries, with significant Earth system impacts.
• Functional biosphere integrity is compromised, evidenced by the transgression of the human appropriation of net primary production boundary.
• Anthropogenic impacts must be viewed systemically, considering the interconnectedness of climate and land system changes.