An agency of the United States government says the effects of climate change cost American taxpayers billions of dollars each year. The U.S. Government Accountability Office, or GAO, investigates how the federal government spends tax money. In a new report, the GAO tries to estimate the amount of federal money spent on disasters related to climate change. The agency considered the possible economic effects of slowly rising temperatures in Earth’s atmosphere and risks to the government. It used information about possible weather conditions based on climate models. A study from the National Research Council notes how large numerical models have become an important tool for climate scientists.