London: Nearly 3.8 billion people could face extreme heat by 2050, and while tropical countries will bear the brunt, cooler regions will also need to adapt, scientists have warned. Demand for cooling will drastically increase in giant countries like Brazil, Indonesia, and Nigeria, where hundreds of millions of people lack air conditioning or other means of beating the heat. According to Nam News Network, even a moderate increase in hotter days could have a severe impact on nations not accustomed to such conditions, like Canada, Russia, and Finland, said scientists from the University of Oxford. In a new study, they examined different global warming scenarios to project how often people in the future might experience temperatures considered uncomfortably hot or cold. They found that the population experiencing extreme heat conditions is projected to nearly double by 2050 if global average temperatures rise by 2°C above preindustrial times. However, most of the impact would be felt this decade as the world ra pidly approaches the 1.5°C mark, explained the study's lead author, Jesus Lizana. "The key takeaway from this is that the need for adaptation to extreme heat is more urgent than previously known," said Lizana, an environmental scientist. New infrastructure, such as sustainable air conditioning or passive cooling, needs to be developed within the next few years to ensure people can cope with dangerous heat. Prolonged exposure to extreme heat can overwhelm the body's natural cooling systems, causing symptoms ranging from dizziness and headaches to organ failure and death. It is often called a silent killer because most heat-related deaths occur gradually as high temperatures and other environmental factors work together to undermine the body's internal thermostat. Climate change is making heatwaves longer and more intense, and access to cooling-especially air conditioning-will be vital in the future. The study, published in the journal Nature Sustainability, projects that 3.79 billion people worldwide could b e exposed to extreme heat by mid-century. This would drastically increase energy demand for cooling in developing nations where the gravest health consequences would be felt. India, the Philippines, and Bangladesh would be among the largest populations impacted. The most significant change in cooling degree days-temperatures hot enough to require cooling, such as air conditioning or fans-were projected in tropical or equatorial countries, particularly in Africa. Central African Republic, Nigeria, South Sudan, Laos, and Brazil saw the biggest rise in dangerously hot temperatures. "Put simply, the most disadvantaged people are the ones who will bear the brunt of this trend our study shows for ever hotter days," urban climate scientist and research co-author Radhika Khosla stated. But wealthier countries in traditionally cooler climates also face a major problem-even if many do not realize it yet. Countries like Canada, Russia, and Finland may experience steep drops in heating degree days-temperatures low enou gh to require indoor heating-under a 2°C scenario. However, even a moderate rise in hotter temperatures would be felt more acutely in countries not designed to withstand heat, the authors noted. In these countries, homes and buildings are usually constructed to maximize sunshine and reduce ventilation, and public transport often operates without air conditioning. Some cold-climate nations may see a drop in heating bills, Lizana noted, but over time, these savings would likely be replaced by cooling costs, including in Europe, where air conditioning is still rare.