Una guerra nuclear, incluso una de car\u00e1cter regional, podr\u00eda alterar tanto el clima global, que miles de millones de personas morir\u00edan de hambre, seg\u00fan el modelo m\u00e1s aproximado desarrollado hasta la fecha por expertos, para tratar de establecer los efectos del llamado \u201cInvierno Nuclear\u201d. El estudio se reinici\u00f3 al producirse la invasi\u00f3n Rusa a Ucrania, que puso al mundo nuevamente en alerta, frente a una potencial guerra nuclear de proporciones catastr\u00f3ficas para la humanidad. Aunque los efectos exactos contin\u00faan siendo inciertos, los hallazgos de la investigaci\u00f3n subrayan los enorme peligros de una guerra nuclear, ofreciendo adem\u00e1s informaci\u00f3n vital sobre c\u00f3mo prepararse para desastres globales de este tipo.<\/p>\n
A nuclear war would disrupt the global climate so badly that billions of people could starve to death, according to what experts are calling the most expansive modeling to date of so-called nuclear winter. Although the exact effects remain uncertain, the findings underscore the dangers of nuclear war and offer vital insights about how to prepare for other global disasters, researchers say.<\/p>\n
The study comes as Russia\u2019s invasion of Ukraine has put the world in \u201cone of the top three most worrisome time periods\u201d for the threat of nuclear war, says Seth Baum, executive director of the Global Catastrophic Risk Institute\u2014behind only the 1962 Cuban Missile Crisis and the 1983 Able Archer incident, when the Soviet Union mistook a NATO military exercise for a real attack. \u201cIt\u2019s a continued reminder that [nuclear war] is really terrible.\u201d<\/p>\n
Scientists have long known massive explosions can throw enough dust, ash, and soot into the air to affect the global climate. In 1815, Mount Tambora in what\u2019s now Indonesia unleashed the largest known volcanic eruption in history. In the following months, its ash rose and spread worldwide, blocking enough sunlight to produce \u201cthe year without a summer<\/a>\u201d\u2014a cold spell in 1816 that resulted in massive crop failures and famine across the globe.<\/p>\n For decades, scientists have warned a similar catastrophe could follow a nuclear war, as fires ignited by hundreds or thousands of nuclear explosions would release millions of tons of soot, blocking sunlight and inducing global environmental effects. Worries about climate effects of nuclear warfare emerged soon after World War II, and studies took off during the Cold War.<\/p>\n Over the past decade, two pioneers of nuclear winter studies, Alan Robock and Brian Toon, have assembled a cross-disciplinary team of scientists to take the calculations further. They turned to the same climate models that underlie global warming studies\u2014but used the models to simulate global cooling instead. \u201cNow, we have the computational capacity to simulate these kinds of things in a sophisticated way,\u201d says Jonas J\u00e4germeyr, a climate change scientist, crop modeler, and team member at NASA and Columbia University.<\/p>\n In new the study, out today in\u00a0Nature Food<\/cite>, the team has attempted to quantify the potential impact of nuclear war on the global food supply by coupling the climate models with simulations of global food production. A previous analysis, led by J\u00e4germeyr in 2020, showed that even a small regional nuclear war between India and Pakistan\u00a0could result in global crop shortages<\/a>. The new study includes six nuclear war scenarios and incorporates models of fisheries as well as farming to get a broader picture of the impact.<\/p>\n The researchers estimated that the various nuclear exchanges would inject between 5 million and 150 million tons of soot into the atmosphere. They simulated the resulting changes in sunlight, temperature, and precipitation, which they then fed to the crop and fishery models. By tracing the reductions in corn, rice, soybean, wheat, and fish harvests, the team estimated the total loss in calories. From there, they calculated how many people would go hungry\u2014assuming international food trade would cease and resources would be distributed optimally in each country.<\/p>\n A few years after a nuclear war between the United States, its allies, and Russia, the\u00a0global average calories produced would drop by about 90%<\/a>\u2014leaving an estimated 5 billion dead from the famine, the researchers report. A worst-case war between India and Pakistan could drop calorie production to 50% and cause 2 billion deaths. The team tried to simulate the impact of food-saving emergency strategies, such as converting livestock feed and household waste to food. But in the larger war scenarios, those efforts did little to save lives.<\/p>\n Baum urges caution in interpreting the estimates. Although the climate models are \u201cexcellent,\u201d he says, there\u2019s too much uncertainty in how humanity would react to such a global catastrophe to get an accurate read on the death toll. Still, the study \u201cmakes a very worthy contribution\u201d to envisioning these scenarios, he adds.<\/p>\n Lili Xia, a climate scientist at Rutgers University, New Brunswick, and lead author on the paper, agrees there\u2019s lots of room to improve the models\u2014including factoring in the effects of soot on ultraviolet radiation and surface ozone and implementing more effective food management techniques. Rather than aiming to forecast exactly how the food catastrophe might play out, she says her group wanted to understand the level of risk humanity faces.<\/p>\n The nightmarish prospects have already inspired others to look for ways to fight the hypothetical famine. David Denkenberger, who co-founded the nonprofit Alliance to Feed the Earth in Disasters, is exploring ideas including scaling up \u201cresilient foods\u201d such as seaweed, repurposing paper factories to produce sugar, converting natural gas into protein with bacteria, and relocating crops to account for an altered climate. He and his research associate Morgan Rivers think those approaches could\u00a0dramatically increase the amount of food available to humans<\/a>. \u201cEven if [a substitute] doesn\u2019t taste as good as sweet corn, it\u2019s better than starving,\u201d he says.<\/p>\n Such thought exercises can also help humanity prepare for the effects of climate change and other disasters, Denkenberger adds. \u201cIt\u2019s not just nuclear winter; resilience helps us with a lot of other catastrophes \u2026 such as a supervolcanic eruption.\u201d<\/p>\n Still, the obvious takeaway for all these scientists is that nuclear war should be avoided at all costs, Rivers says. \u201cTheir analysis is showing something really critical to transmit: that nuclear winter is really, really bad.\u201d<\/p>\n