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Agricultural areas in 155 countries depend on atmospheric moisture from forests in other nations for up to 40 per cent of their annual rainfall, a new study has shown.
About 18 per cent of precipitation in 105 countries is recycled from their national forests, the study published in Nature Water found. Moisture from forests globally supports 18 per cent of crop production and 30 per cent of crop export studied, it noted.
The authors of the study assessed that countries producing, exporting and importing food are dependent on their upwind forest counterparts due to a complex web of atmospheric moisture flows between nations.
These flows demonstrate how two countries are inter-dependent. For instance, forested countries import crops from downwind crop producers and exporters.
The study noted that Brazil supplies moisture to countries such as Paraguay, Uruguay, and Argentina but receives over 77 per cent of annual crops through imports.
This flow type provides an ideal example of mutually beneficial bilateral cooperation where one country benefits from stable crop imports by conserving its forests, and the other benefits from favourable climatic conditions supporting agricultural production.
The analysis further noted that Brazil supplies moisture to agricultural areas in countries like Peru, Ecuador, Bolivia, Paraguay, Uruguay, and Argentina, which collectively account for 10 per cent of global crop export. Thus, countries outside South America are indirectly dependent on moisture from Brazilian forests, the study noted.
The assessment stated that crop production in Ukraine depends on moisture being supplied by forests in Russia. But changes to Russian forests could not just potentially affect crop export from Russia but also cause a cascading effect on other notable crop exporters, such as Ukraine and Kazakhstan.
“The Russian invasion of Ukraine in 2022 demonstrated that a disruption in crop production and export from Ukraine can lead to propagating shocks of global crop distribution along the supply chain. Consequently, food access in the Middle Eastern, Asian and African countries relying on staple cereal export from both Russia and Ukraine were affected,” it noted.
The assessment found such interwoven connections between countries highly reliant on forest precipitation like Brazil, Argentina, Canada, Russia, China, and Ukraine. These nations are often high crop producers and exporters.
The scientists said Brazil is exceptional due to its dependence on nationally recycled moisture.
Forests in Brazil recycle nearly 9 per cent of the national annual rainfall on its agricultural areas, contributing to 6 per cent of global crop production and 9 per cent of global crop export.
Similarly, Argentina is a hotspot for dependence on transboundary moisture, receiving about 14 per cent of its annual precipitation from transboundary sources, primarily Brazil, the study said.
According to the study, Argentina contributes 3 per cent of global crop production and 6 per cent of global crop export.
Tropical forests supply high percentage of rainfall to downwind agricultural countries, compared to extratropical forests.
“Forests in countries like Brazil, Indonesia, and the Democratic Republic of Congo (DRC) safeguard a high percentile of precipitation to national agricultural areas, collectively accounting for 10 per cent of global crop production,” it said.
The DRC, Bolivia, Brazil, Peru, Canada and Russia are crucial as suppliers of moisture and of crops. Together, they are responsible for 13 per cent of global crop production and 20 per cent of global crop export, it said.
“Approximately 46 per cent and 10 per cent of the highly dependent agricultural areas have their respective green and blue water requirements for all crops fulfilled, despite some receiving only 6 per cent of their annual precipitation from forests,” the study found.
The scientists underlined that their assessment implies that strategically conserving forests located upwind of agricultural areas could be leveraged to safeguard global crop supply.