One meta-analysis found that exposure to sounds like running water and chirping insects were linked to significant improvements in key health metrics such as blood pressure and cognitive ability. In other words, “an environment that is filled with natural sounds feels safe and allows us to let our guard down.” Unwanted noise, by contrast — like the blaring of a car alarm — makes people feel like they’re in danger, increasing people’s “stress and annoyance.” And for all the sounds the Earth is losing each year, there certainly are many new and more grating ones to take their place.