SUSTAINABILITY. Response to Comment on "Planetary boundaries: Guiding human development on a changing planet"

Area of Science:

• Environmental science
• Hydrology
• Planetary boundaries

Background:

• A recent study claims global freshwater consumption exceeds planetary boundaries.
• This claim is based on specific, high-range estimates of water cycle components and definitions of consumption.
• This contrasts with mainstream assessments of global water resource availability.

Purpose of the Study:

• To re-evaluate claims regarding global freshwater consumption relative to planetary boundaries.
• To highlight discrepancies between specific high-estimate analyses and mainstream global assessments.
• To underscore the importance of standardized definitions and robust data in water resource studies.

Main Methods:

• Analysis of mainstream global water consumption assessments.
• Comparison with alternative methodologies using high-range water cycle estimates.
• Identification of definitional differences in water consumption and water cycle components.

Main Results:

• Mainstream assessments indicate freshwater consumption is within planetary boundaries.
• Discrepancies arise from differing definitions of water consumption and water cycle components.
• Extrapolation from single case studies may lead to overstated conclusions.

Conclusions:

• Current global freshwater consumption, based on widely accepted data, does not appear to exceed planetary boundaries.
• Clarification of water cycle component definitions and improved global databases are crucial.
• Further research should focus on standardized methodologies for assessing global water resources.