A Super El Nino in 1877 led to a famine that killed an estimated 50 million people, between 3 and 4 percent of the world’s population at the time. Deaths were concentrated in developing countries including China, India, and Brazil, which I am assuming would have had large populations of rural subsistence farmers at the time.
The article talks about how the impending 2026-2027 El Nino may be comparable in terms of heat and drought, but we have much better forecasting of what to expect and technology to deal with it. The article stops short of discussing how to actually deal with it, but I would assume some combination of stockpiling food in advance, international trade, international coordination and assistance, and (temporarily boosted, long-term unsustainable) irrigation. Also not discussed in the article are the self-inflicted geopolitical events (both the Middle East and Ukraine, which is an important grain exporter) that are making growing and trading food more challenging, right when this is most harmful. You can provide subsidies for farmers and consumers if prices spike, but at some point that will not help if there are really absolute shortages – if that happens, let’s hope it’s shortages of preferred foods rather than a shortage of absolute calories.