Irrigated areas drive irrigation water withdrawals

Area of Science:

• Environmental Science
• Hydrology
• Agricultural Science

Background:

• Sustainable global freshwater management hinges on accurate irrigation water demand estimates.
• Current methods by the Food and Agriculture Organization (FAO) and Global Models are complex and potentially unreliable.

Purpose of the Study:

• To demonstrate that complex models for irrigation water withdrawals are unnecessarily complicated.
• To propose a more parsimonious and transparent approach for estimating irrigation water demand.

Main Methods:

• Analyzing the influence of irrigated areas and their uncertainties on existing models.
• Developing a simplified model that directly links irrigation water withdrawals to irrigated areas.

Main Results:

• Existing FAO and Global Model estimates are heavily influenced by irrigated area data and associated uncertainties.
• A parsimonious model based solely on irrigated areas yields comparable results to complex models.

Conclusions:

• Complex sub-models in global irrigation water withdrawal assessments are largely redundant.
• A simplified, area-focused approach offers a more robust, transparent, and parsimonious method for water security policy.