Marine wild-capture fisheries after nuclear war

Abstract

Nuclear war, beyond its devastating direct impacts, is expected to cause global climatic perturbations through injections of soot into the upper atmosphere. Reduced temperature and sunlight could drive unprecedented reductions in agricultural production, endangering global food security. However, the effects of nuclear war on marine wild-capture fisheries, which significantly contribute to the global animal protein and micronutrient supply, remain unexplored. We simulate the climatic effects of six war scenarios on fish biomass and catch globally, using a state-of-the-art Earth system model and global process-based fisheries model. We also simulate how either rapidly increased fish demand (driven by food shortages) or decreased ability to fish (due to infrastructure disruptions), would affect global catches, and test the benefits of strong prewar fisheries management. We find a decade-long negative climatic impact that intensifies with soot emissions, with global biomass and catch falling by up to 18 ± 3% and 29 ± 7% after a US–Russia war under business-as-usual fishing—similar in magnitude to the end-of-century declines under unmitigated global warming. When war occurs in an overfished state, increasing demand increases short-term (1 to 2 y) catch by at most ∼30% followed by precipitous declines of up to ∼70%, thus offsetting only a minor fraction of agricultural losses. However, effective prewar management that rebuilds fish biomass could ensure a short-term catch buffer large enough to replace ∼43 ± 35% of today’s global animal protein production. This buffering function in the event of a global food emergency adds to the many previously known economic and ecological benefits of effective and precautionary fisheries management.

Extreme Ozone Loss Following Nuclear War Results in Enhanced Surface Ultraviolet Radiation

“…Changes in spectral integrals show that greatest increase is for DNA damage, which increases by up to 140% in the global war case and there is a risk of insufficient vitamin-D during the first few years following a global war. Assessments of impacts on agriculture and fisheries like those done by Jägermeyr et al (2020) and Scherrer et al (2020) for a regional nuclear war need to include the effects of UV and surface O 3 changes, and need to be done for the larger and differently sequenced effects that are generated by a global nuclear war.…”

“…Effects from these climatic changes for regional wars have been discussed in Robock, Oman, Stenchikov, Toon et al (2007), Stenke et al (2013), Mills et al (2014. Jägermeyr et al (2020) found large agricultural changes and Scherrer et al (2020) predicted significant effects on fisheries in response to climatic changes from a regional nuclear war. Scherrer et al (2020) also found larger effects for the global war case.…”

“…Jägermeyr et al (2020) found large agricultural changes and Scherrer et al (2020) predicted significant effects on fisheries in response to climatic changes from a regional nuclear war. Scherrer et al (2020) also found larger effects for the global war case. However, neither study included the effects of O 3 or UV changes, which would likely lead to additional losses especially related to global grain productivity.…”

Global Famine after Nuclear War

“…Fish are another important food resource, especially in terms of protein supply. Nuclear war would reduce the wild fish catch 12 , but the reduction would be less than for land agriculture (Figure 2b), since reduction in oceanic net primary productivitythe base of the marine foodweb-is moderate (from 3% in 5 Tg to 37% in 150 Tg), and temperature changes are less pronounced (Figure 1). Terrestrial agricultural production dominates the total calorie change of crops and fisheries combined (Figure 2c), since global crop production is 24 times that of wild fisheries and staple crops contain around five times more calories than fish per unit mass 21 , 22 .…”

“…In 1980s, investigations of nuclear winter impacts on global agricultural production 7 and food availability 8 for 15 nations, but new information now allows us to update those estimates. Recently, several studies analyzed changes of major grain crops 9,10,11 and marine wild-catch fisheries 12 for different scenarios of regional nuclear war using sophisticated models. However, the impact on the total food supply available to humans is more complex.…”