A new study published recently in PLOS Medicine reminds us that lives will be lost elsewhere as long as air conditioners draw their energy from oil, gas, or coal. Why? Blame air pollution—our addiction to dirty fuels throws particulate matter and ozone into the air. Electricity production is already the second-largest source of greenhouse gas emissions in the United States, and as our ACs eat up more of it, we get more emissions.

The authors believe their study is the first to estimate how many people may die from an increased dependence on AC as temperatures rise. The conclusion? The increased air pollution could lead to an average of 654 more deaths annually in the U.S. from particulate matter, and 315 additional deaths from ozone by midcentury. Per the study, this could amount to a $9 billion annual drain on the economy.