Scientists have discovered that global weather cycles such as El Niño affect as much as two-thirds of the world’s cropland. The researchers say their findings have the potential to improve agricultural planning capabilities and resilience to weather phenomena.
Researchers studied the effects of the El Niño-Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and the Indian Ocean Dipole (IOD) on global crop productivity over the period from 1961 to 2010.
The study was led by Finland’s Aalto University, with collaboration from researchers at Columbia University, Vrije Universiteit Amsterdam, Potsdam Institute for Climate Impact Research (PIK), and University of Bonn.
Their findings were published on Wednesday in the journal Nature Communications. According to the authors, their work is the first global study to explore the effects of these climate oscillations on worldwide food production.
Researchers examined productivity of 12 major crop types over a 50-year period. Using computor simulations, they were able to isolate the impact of climate on crop productivity and assess the data at a sub-country scale. According to the study, this method is particularly helpful for geographically large countries such as China and the United States, where the effects of climate oscillations “might have substantial spatial variability within each country’s territory.”
The analysis showed that one or more climate oscillation has statistically significant impacts on crop productivity in 67% of the world’s cropland. These areas produce around two-thirds of global food crops and house 68% of the world’s population.
El Niño and its counterpart La Niña have previously been shown to affect crop yields in parts of Latin America, South Asia, southern Africa and the US. NAO, meanwhile, has been shown to affect crop production in parts of Europe, China and the US, while IOD is known to impact Australian wheat crops. The new analysis confirmed previous evidence and revealed that climate oscillations affect agricultural productivity in other regions as well.
“Our study showed that the North Atlantic Oscillation, NAO, significantly affects crop production in many parts of Europe, but also in North Africa and the Middle East,” Aalto University assistant professor Matti Kummu said in a press release.
NAO refers to sea level pressure fluctuations between the Icelandic Low, a persistent low-pressure area near Iceland, and the Azores High, a persistent high-pressure area south of the Azores. Large pressure differences between the two areas result in stronger winds that bring warm, moist air to Europe from the Atlantic, while smaller pressure differences lead to weaker winds and colder European winters with less rain.
Researchers found that when there is a strong pressure difference, it reduces crop productivity in Europe, North Africa and the Middle East. When the air pressure difference is weaker, the same regions showed increased crop productivity.
The analysis showed that in Europe, a strong pressure difference caused as much as a 2% decline in crop productivity compared to average. The effect was even more noticeable in areas including Spain and the Balkans, where productivity dropped up to 10% in years with a large pressure difference. Parts of North Africa and the Middle East also showed crop productivity reductions as high as 6%.
The authors say the results of their study can help improve the ability to cope with natural hazards connected to these climate oscillations in many areas around the world.
“During recent years, researchers’ ability to predict these oscillations has improved significantly,” said Matias Heino, a doctoral candidate at Aalto University. “With this research, we highlight the potential of utilising this improved forecasting skill in agricultural planning.”
Heino noted doing so “could improve the resilience of agriculture to climate related shocks, which can improve food security in many areas across the globe.”