Air conditioners will not save us from the heat.

Parts of Europe and Asia are facing record-breaking heatwaves this summer, accompanied by prolonged droughts and devastating wildfires. According to reports, more than 10,000 excess deaths were recorded in European countries during a heatwave in late June 2026. These figures refer to mortality rates above expected levels due to all causes, not final numbers directly attributed to heat. In 2003, heat-related deaths in Europe exceeded 70,000, while estimates for 2022 suggest around 61,672 deaths linked to extreme temperatures. As a result, cooling buildings has become increasingly critical, not just for comfort, but for health and survival. The demand for cooling is accelerating rapidly. One obvious solution is the expansion of air conditioning, but it is neither the sole nor a globally sustainable answer. New research published in Nature Reviews Clean Technology indicates that building cooling accounts for nearly 10 percent of global electricity consumption. This figure is expected to rise as heatwaves become more frequent, intense, and prolonged. The International Energy Agency predicts that the number of air conditioners worldwide could increase from 1.6 billion to 5.6 billion by 2050. Cooling should not become a privilege. Wealthier nations with widespread air conditioning, such as the United States, manage high temperatures primarily through these devices. However, such solutions are inaccessible to billions of people in poorer countries. A study published in Nature Communications in 2021 estimated that between 64 and 100 million households connected to the electrical grid in Brazil, India, Indonesia, and Mexico might require cooling by 2040, but many would not afford air conditioners or their usage. Passive cooling of homes offers a potential alternative. Researchers analyzing a new review paper have explored the possibility of addressing part of the problem through passive cooling methods. While they won’t maintain every room at exactly 22 degrees Celsius, these techniques can mitigate temperature peaks, reduce the runtime of air conditioners, lower energy bills, and ease pressure on power systems. They are particularly beneficial in poorer communities and during power outages. Analysis shows that proper building design, shading, natural ventilation, and advanced materials in hot climates could reduce cooling needs by up to 80 percent. This does not mean rejecting air conditioners entirely. During extreme heat, they save lives. But it is unreasonable to allow buildings to turn into ovens and then rely on energy-intensive devices that consume large amounts of electricity and raise urban street temperatures. Researchers from UNSW Sydney and RMIT University have analyzed known solutions, such as creating shade and nighttime ventilation, along with new materials capable of radiating heat into space. These innovations aim to complement traditional cooling methods rather than replace them entirely. Air conditioners are not a sufficient solution because they transfer heat from a room to the outside using refrigerants, compressors, and electricity, similar to how a refrigerator cools its interior while heating the kitchen. Studies show that waste heat from air conditioners in densely built urban areas can raise air temperatures by approximately 1 to 2 degrees Celsius. Energy demand often rises precisely when heat can reduce its production. During droughts, water levels drop, and rivers warm, forcing nuclear plants that use water for cooling to sometimes reduce output to avoid threatening ecosystems. For example, France’s nuclear fleet, which has a total installed capacity of 62.9 gigawatts, reduced nuclear production by 4.1 gigawatts, or about 6.5 percent of its installed capacity, during the heatwave in June 2026. Droughts also decrease hydroelectric generation and can limit operations at thermal plants requiring substantial water for cooling.