American scientists from the University of Texas have calculated the amount of water consumed by global agriculture to grow important crops. The study was published in the scientific journal magazine Environmental Research Letters (ERL).
The team examined 175 crop species from 1990 to 2019 for their green and blue water footprints. Green water is moisture from rainfall, while blue water is irrigated from shallow soil springs.
The analysis found that almost 80% of crops analyzed in 2019 required less water per tonne compared to 1990. But efficiency gains have not been enough to stop agriculture’s increasing global water footprint. Over the last 30 years, this amount has increased by almost 30%, reaching 6.8 trillion cubic meters per year, or approximately 2,400 liters per person per day.
Almost 90% of the total increase occurred between 2000 and 2019, and the authors attribute this to three main socioeconomic factors.
First, accelerated globalization and economic growth have significantly increased the consumption of various imported crops and plant products. Second, global diets have shifted towards foods containing more water, such as animal products, sugary drinks, and sugary and fatty foods.
Third, for many governments, energy security has encouraged crop-based biofuel production.
According to the research, the largest water consumers are India, China and the USA. However, the overall increase in water footprint has occurred mostly in tropical regions and has often been accompanied by other environmental impacts such as deforestation and biodiversity loss.
The authors suggest that great potential remains for improving efficiency in crop water use, moving production to less water-stressed regions, increasing the adoption of less water-intensive diets, and minimizing the need for first-generation biofuels.
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