A nuclear winter is a theoretical concept, but if the climate scenario expected to follow a large-scale nuclear war, in which smoke and soot from firestorms block sunlight, came to fruition, global temperatures would sharply drop, extinguishing most agriculture. A nuclear winter could last for more than a decade, potentially leading to widespread famine for those who survive the devastation of the bomb blasts. Now, a team led by researchers at Penn State have modeled precisely how various nuclear winter scenarios could impact global production of corn - the most widely planted grain crop in the world. They also recommended preparing "agricultural resilience kits" with seeds for faster-growing varieties better adapted to colder temperatures that could potentially help offset the impact of nuclear winter, as well as natural disasters like volcanic eruptions.
In findings recently published in Environmental Research Letters, the team reported that the level of corn crop decline would vary, depending on the scale of the conflict. A regional nuclear war, which would send about 5.5 tons of soot into the atmosphere, could reduce world-wide annual corn production by 7%. A large-scale global war, injecting 165 tons of soot into the atmosphere, could lead to an 80% drop in annual corn yields. In all, the study simulated six nuclear war scenarios with varying soot injections.
Because of the crop's global significance, the researchers chose to model corn's collapse in a nuclear winter to represent the expected fate of agriculture overall, according to study first author Yuning Shi, associate research professor in Penn State's Department of Plant Science. He noted that an 80% drop in global crop production would have catastrophic consequences, leading to a widespread global food crisis. Even a 7% drop in global crop production would have a severe impact on the global food system and economy, likely resulting in increased food insecurity and hunger.
The simulations were possible thanks to the Cycles agroecosystem model, created a few years ago by scientists in Penn State's College of Agricultural Sciences, including lead developer Armen Kemanian, professor of production systems and modeling and corresponding author on this study. Using high-performance computing and considering atmospheric conditions, Cycles enables large-scale, high-resolution, multi-year simulations of crop growth by meticulously tracking the carbon and nitrogen cycles within the soil-plant-atmosphere system.
"We simulated corn production in 38,572 locations under the six nuclear war scenarios of increasing severity - with soot injections ranging from 5 to 165 tons," Shi said. "This investigation advances our understanding of global agricultural resilience and adaptation in response to catastrophic climatic disruptions."
In addition to considering the effects of massive amounts of soot in the atmosphere, the researchers modeled the increase in UV-B radiation - a type of ultraviolet radiation that can lead to DNA damage, oxidative stress and reduced photosynthesis in plants - that would reach Earth's surface in a nuclear winter that could further limit agriculture.
