In a recently published study, researchers offer a new tool to compare how different crops affect the environment in different regions.
Named PLANTdex, the tool assesses the environmental impact of a crop by considering five key indicators — greenhouse gas emissions, freshwater biodiversity loss, marine biodiversity loss, land biodiversity loss, and water resource depletion — study co-author Mark Jwaideh, nature data and risk analytics lead at the University of Oxford, told Mongabay by email.
For each crop, PLANTdex combines these five indicators into one score at a high resolution of 9 by 9 kilometers (5.6 by 5.6 miles).
“This granularity enables the identification of specific regions where crop production is more or less environmentally impactful, facilitating targeted interventions and policy decisions,” Jwaideh said. “This approach enables stakeholders to pinpoint environmental hotspots to make informed decisions on crop commodity sourcing or where better management is required.”
To build PLANTdex, Jwaideh and colleague Carole Dalin, an associate professor at University College London, used crop production and environment impact data from 2000 to assess 16 crops globally. While old, the year 2000 provided the most consistent data for building the tool’s models, Jwaideh said.
Based on this data, the study found high PLANTdex scores, indicating high environmental impacts, for crops planted in Central America, Southern Europe, the region between the Black and Caspian seas, Southern Africa, and South, East and Southeast Asia. PLANTdex scores were lower for midwestern North America, certain areas of Central Europe and Russia, western South Asia and parts of Central Africa and South America.
When looking at subnational data, PLANTdex identified higher environmental impacts in two distinct areas. First were areas along rivers, which the researchers attributed to “high aquatic impacts of nitrogen and phosphorus fertilizer application such as in South Asia along the Ganges River.” Next were higher-elevation areas and slopes, possibly due to “increased nutrient run-off, which adversely affects aquatic biodiversity,” the authors write.
“Environmental impacts of crop production vary significantly at sub-national levels, emphasising the need for localised assessments,” Jwaideh said.
Crop type also mattered. Globally, crops like rapeseed, rice, cotton and oil palm were identified by PLANTdex “as the most environmentally impactful crops to produce per dry tonne,” while wheat, maize, sugar beet and sugarcane showed smaller impacts.
The researchers write it’s desirable to find crops that have low environment impacts and higher production levels. While their tool did not find such significant relationships when looking at entire countries, some trends emerged when zooming into smaller areas. For example, for crops like barley, cotton, maize, potato, rice, soybean, sugarcane and wheat, high production areas seemed to have lower environmental impacts. Meanwhile, oil palm and rapeseed showed higher environmental impacts in high production areas.
While the tool was originally built with data from 2000, “more recent iterations of PLANTdex now include timeseries data with updates to all five underlying indicators,” Jwaideh said.
Banner image of oil palm plantation in Malaysia by Rhett A. Butler/Mongabay.