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The sweltering temperatures in the spring and summer of 2012 contributed to devastating crop failure causing $41 billion in losses nationally. The past 20 years of carbon emissions have caused the risk of similar extreme heat waves to skyrocket. Heat waves like this used to occur once every 100 years. Deep Sky’s research found they will now happen once every five. Our carbon emissions have caused the risk of an extreme heat wave to increase 20-fold. 

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Not only should we expect a higher frequency of heat waves – we should expect them to be even more severe. Just two years before the 2012 drought, Europe experienced a record-shattering heat wave that caused crop failure, wildfires, and over 56,000 deaths. It was completely unprecedented both in terms of temperature anomaly and the size of the area it covered.

Crops like wheat have specific temperatures above which they will die. 27.8°C and 32.8°C are two important thresholds for wheat at different times in their growth. Research shows that the risk of breaching these thresholds, and killing crops, has grown, mirroring Deep Sky’s findings about prolonged 2012-level temperatures. As the frequency and severity of heat waves increase, critical thresholds will be breached, causing non-linear impacts on crop production, food prices, and many other widespread economic impacts. The consequences will be grave.

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The 2012 drought was the greatest US drought since the Dust Bowl of the 1930s. Failure of corn, soybean, and wheat crops caused rapid price increases all the way up the food chain in meat and processed foods. Direct food price increases caused losses of $41 billion, but economy-wide analysts believe the overall cost was almost double that. This kind of agricultural and economic disruption will happen more frequently and on even greater scales. 

Conventional climate modeling approaches have a poor track record of predicting extreme events like this, which are exactly what we need to be able to anticipate. New modeling techniques allow better assessment of this risk. The temperatures seen in 2012 in the US breadbasket in May, June, and July exceeded all previous records in the data. Predicting unprecedented events cannot rely on past data alone, or the models will predict that the event is impossible. New approaches like UNSEEN modeling generate thousands of plausible events, from which we can do robust statistical analysis and better understand risk. This modeling approach has demonstrated the capacity to predict extreme events – events that have been completely unanticipated using conventional approaches. Deep Sky used UNSEEN modeling in this analysis and found crop failure risk has skyrocketed. 

Thanks to climate change, we’re living in unprecedented times. Our models need to adjust accordingly.

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Methodology

This analysis assessed the risk of the heatwave and drought conditions in the main crop-producing region of the United States that had devastating consequences for the agriculture sector in 2012. There are not enough examples of past extreme events on which to base projections about future heat waves, droughts, and storms. Studying climate risk in the era of climate change requires a new approach. 

UNSEEN modeling combined with extreme value statistics offers a new approach for the risk assessment required to understand future climate risk. This analysis used UNSEEN modeling to generate a robust sample of temperature and precipitation projections for the region of the United States most severely affected by the drought and crop failure in 2012. This region is also the primary crop-producing region of the country. The UNSEEN ensemble was used to analyze the probability of such an event occurring again. The results, outlined in greater detail in the Technical Appendix (available upon request), show that the probability of a similar heatwave event has increased dramatically in the past forty years. 

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