Air conditioning plays a critical role in saving lives during extreme heat events but also contributes significantly to global warming, according to experts. In the United States alone, air conditioning is estimated to save more than 5,000 lives annually, with a recent study finding nearly 58,000 lives saved between 2010 and 2020. However, the environmental costs of cooling are mounting as global temperatures rise and demand for air conditioning surges worldwide.
The escalating need for cooling is driven by increasing heat waves that now affect nearly every continent. United Nations officials estimate that heat-related deaths reach approximately half a million annually. As temperatures rise, air conditioning use has surged, with electricity demand for cooling projected to triple over the coming decades, according to the International Energy Agency (IEA) and the United Nations Environment Programme (UNEP).
Most electricity used for cooling still derives from fossil fuels, which releases significant amounts of greenhouse gases. The UN projects that carbon emissions associated with air conditioning will increase from 4.5 billion tons currently to 7.2 billion tons within 25 years—a level comparable to current emissions from the United States and Europe combined.
“Air conditioning works, but from a climate change perspective, it is not ideal,” said Kai Chen, an epidemiology professor at Yale School of Public Health and lead author of the study. Chen highlighted the dilemma that excessive use of air conditioning can worsen climate change without delivering additional health benefits. His team analyzed 30 million U.S. death records over 11 years, finding that air conditioning saved an average of 5,267 lives annually, especially in southern states such as Arizona, Florida, Texas, and Louisiana. Northern states showed fewer lives saved, reflecting lower exposure to extreme heat.
Chen noted that over half of air conditioning use may be considered excessive, citing office environments where indoor temperatures are often set uncomfortably low, causing some workers to wear sweaters during summer months. The study suggested that maintaining cooling at around 75 degrees Fahrenheit (24 degrees Celsius) is a reasonable target, as cooling beyond this level does not yield additional life-saving benefits but does increase carbon emissions.
Beyond the carbon footprint, widespread air conditioning also exacerbates urban heat island effects by releasing waste heat outdoors and adds to local pollution through increased electricity consumption. This poses additional environmental and health challenges, particularly in densely populated cities.
Energy constraints and climate concerns have prompted some countries to introduce measures limiting air conditioning use. Bangladesh, Cambodia, Jordan, Malaysia, the Philippines, the Seychelles, Singapore, and Sri Lanka have implemented temperature restrictions or mandated cooling shutdowns on certain days. India proposed similar limits in 2025 amid a global energy crunch influenced by geopolitical developments.
The issue of equitable access to cooling remains a major challenge. Many vulnerable populations globally cannot afford air conditioning, forcing difficult choices between essential healthcare and keeping homes cool during heat waves. “Thermal comfort should not be a luxury. It’s becoming a prerequisite for health, dignity, and increasingly survival,” said Eleni Myrivili, UNEP’s chief heat officer.
Efforts are underway to promote “smarter and more equitable cooling” rather than simply reducing use, with cities and countries exploring comprehensive strategies. Singapore is often cited as a model, employing urban greenery, efficient cooling and ventilation standards, and early warning systems to mitigate heat. These measures have contributed to energy savings of approximately $35 million annually and lowered temperatures by up to 14 degrees Fahrenheit (8 degrees Celsius) in some areas.
As global temperatures continue to rise, balancing the life-saving benefits of air conditioning with the urgent need to limit its environmental impact remains a significant challenge for governments, experts, and communities worldwide.