“Food shocks” — sudden disruptions of food production — have become more frequent over the last half-century, driven by an increase in extreme weather events and geopolitical instability, according to a new study published in the journal Nature Sustainability.

Led by researchers at the University of Tasmania, the study examined 226 food production shocks across 134 countries between 1961 and 2013. The scientists considered major disruptions to crops, livestock, fisheries, and aquaculture caused by droughts, floods, and other extreme weather events, as well as by outbreaks of violent conflict.

“In recent decades, we have become increasingly familiar with images in the media of disasters such as drought and famine around the world,” Richard Cottrell, a socioecologist who studies food security at the University of Tasmania and lead author of the new study, said in a statement. “Our study confirms that… shocks have become more frequent, posing a growing danger to global food production.

Cottrell and his colleagues found that crops and livestock are more shock-prone than fisheries and aquaculture. They also identified shock hotspots for each sector: South Asia for crops, the Caribbean for livestock, Eastern Europe for fisheries, and South America for aquaculture.