Open any news feed from the past few months, and the disasters arrive in a stream: smoke reaching dangerous levels throughout Canada and flash floods in Ottawa, Montréal and Toronto; heat and drought arriving together on every continent.Driven by climate change, these events are happening more often, and rather than remaining isolated, they cause cascading, interrelated effects.Now enter the “super” or even “Godzilla” El Niño developing in the tropical Pacific. This phenomenon changes weather patterns globally, potentially bringing more extreme heat, drought and flooding. Although it’s a natural climate phenomenon, scientists are concerned about the unprecedented rate of surface warming. The U.S. National Oceanic and Atmospheric Administration (NOAA) has declared a greater than 83 per cent probability of strong to very strong El Niño conditions during January to March 2027. Historical precedents are sobering, with major El Niño events of 1982-83, 1997-98 and 2015-16 leading to extreme flooding in some regions, severe drought in others, and widespread disruption to ecosystems and economies.Now imagine if hospitals were overrun with respiratory events due to wildfire smoke, migraines, heatstroke and delirium. At the same time, the electricity grid could go down due to overwhelming demand from the use of air conditioning systems.If that scenario sounds plausible, it’s because every element has already happened in Canada, just not all at once. We call these scenarios polycrises, to represent multiple connected crises occurring simultaneously. We’ve seen these before, such as the 2013 Calgary floods, the 2020 COVID-19 pandemic and the 2023 Northwest Territories wildfires that required evacuation.The toll of polycrisis on health careThe health-care system deserves special consideration when preparing for polycrises. Canada’s health-care system is over capacity on a normal day, with now-familiar hallway medicine, long wait times, surgical delays, understaffing and insufficient primary and long-term care. Canadian access to care ranked ninth of 10 peer countries in a 2025 study, above only the United States. Now imagine adding severe wildfire smoke, a flood causing energy outages and a new viral illness. It’s easy to imagine health-care access and quality declining. Health care suffers at the centre of polycrises. Wildfire smoke has contributed to 1,900 premature deaths annually and $18 billion in costs in Canada. Evidence shows that smoke increases all-cause mortality and causes exacerbations of cardiovascular disease, respiratory conditions, neurologic diseases like multiple sclerosis and migraines. It can trigger stroke and delirium, affect fetal health and has been associated with developing dementia. During the 2023 wildfires, Ontario asthma-related emergency visits increased by 23.6 per cent. Floods disrupt transportation, supplies and patient discharge, while evacuations overwhelm communities, like when 20,000 Northwest Territories residents fled to Alberta in 2023. Supply-chain interruptions threaten access to medications and medical equipment, as seen during COVID-19. These crises disproportionately affect underhoused individuals, people with disabilities, lower-income households and Indigenous communities.Energy implicationsA strong El Niño can put the entire energy system under strain, just when the health system is most vulnerable.The effects begin months earlier. Milder winters, altered precipitation and reduced mountain snowpack diminish spring runoff and hydroelectric inflows, leaving reservoirs with less stored energy as summer demand peaks arrive. It can also influence the likelihood of extreme summer heat, which often coincides with periods of low wind output. In June 2026, Europe experienced a heat dome accompanied by a wind drought, reducing wind generation just as soaring temperatures drove up electricity demand for cooling.In extreme heat, solar power has lower capacity – known as derating – losing roughly 0.4 per cent for every degree above 25°C, and dims further under wildfire smoke. Gas turbines also lose capacity to hot-air derating on the hottest afternoons.As with the broader polycrisis, the primary issue is convergence. Demand rises precisely when many supply sources are constrained, leaving the grid with less room to absorb the next shock.The shared patientEnergy poverty is where the energy system and health system share a patient. While hospitals have backup power and contingency plans, the greatest risks lie in the community. The households least able to afford cooling, air filtration or backup power are the same populations over-represented in heat and smoke morbidity. British Columbia’s 2021 heat dome led to more than 619 deaths, primarily among the elderly and those who lived in under-resourced communities.The heat dome that fills emergency departments with heatstroke and delirium is the same weather system derating the gas turbines that power hospital wards. The smoke triggering asthma exacerbations also reduces the solar output flowing into the grid. The insulin requiring refrigeration, the elevators in seniors’ residences and the oxygen concentrators in patients’ homes all depend on electricity precisely when demand is greatest. This is the defining property of a polycrisis: interconnected failures that neither the energy system nor the health-care system can prepare for alone.What resilience looks likeThe encouraging part is that the two systems share their defences as surely as they share their failures. Storage, demand flexibility, interties (transmission links that let grids share electricity), backup power at critical facilities and cooling centres with assured power: every investment that hardens the grid against El Niño-pattern stress also protects health outcomes. One system’s resilience budget is the other’s prevention budget. Energy-affordability support is preventive medicine delivered through a utility bill. The El Niño forecast’s real value is lead time. We must act on this warning and secure backup power, fund cooling centres, bolster critical supply chains and identify patients whose health depends on the grid. The time to prepare for a polycrisis is before the emergency is at our doorstep.This story was co-authored by Luke Killam, co-founder and CEO of GreenKey Energy, an independent energy consultancy.The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.