Very variable climate, very variable yields

Variability. It’s something we tend to forget about, especially when it comes to climate change. Most research into the effects of climate change on crops focuses on changes in the average temperature. In reality, climate change is more complicated than just an increase in average global temperature. It is expected to cause an increase in temperature variation, that is, more frequent extreme temperature events and larger fluctuations in temperature from day to day, season to season, and year to year. This greater variation leads to an increased chance of extreme warming events that can adversely affect crop yields.

So how does variation in temperature affect crop yields exactly? Ray et al. (Ray et al., 2015, Nature Communications, 6:5989) set out to determine how variations in temperature and precipitation have affected crop yields, and more specifically, variation in crop yields. Stable crop yields provide a stable food supply and stable income for farmer, while highly variable crop yields can affect food prices, food security, and the ability of farmers to continue farming. Looking at historical data on climate variability and yields of wheat, rice, soybean and maize, Ray et al. found that approximately one-third of variation in crop yield on a yearly basis was due to variations in climate. In some regions, such as the Midwestern United States, as much as 75% of the variability in crop yield was due to climate variability. Increasing climate variability is thus a serious issue that challenges global food security.

So what is an appropriate solution? As Ray et al. point out, some agricultural regions showed no relationship between crop yield and climate variability, since farmers were already adapting their practices to a changing climate. Therefore, a cursory glance suggests that to ensure food security in the face of a changing climate, global agriculture needs to adapt to the changing climate, or risk catastrophe.

Stay safe and stay informed,


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