Seems like the Earth Day related crowd sourcing project to create the first global soundscape by encouraging smartphone owners around the world to download and use an app developed to record the sounds around them is interesting, though it's unclear what scientific value it would have. Is there any scientific value to understanding soundscapes on a global basis?
Remote sensing using passive sonar and seismograms, which are acoustic or near-acoustic signals, works on the principle of the inverse problem. While the object or phenomenon of interest (the state) may not be directly measured, there exists some other variable that can be detected and measured (the observation), which may be related to the object of interest through the use of a data-derived computer model.
Soundscape ecology is the study of sound within a landscape and its effect on organisms. Sounds may be generated by organisms (biophony), by the physical environment (geophony), or by humans (anthrophony). Soundscape ecologists seek to understand how these different sound sources interact across spatial scales and through time. Variation in soundscapes may have wide-ranging ecological effects as organisms often obtain information from environmental sounds. Soundscape ecologists use recording devices, audio tools, and elements of traditional ecological analyses to study soundscape structure. Increasingly, anthrophony, sometimes referred to in older, more archaic terminology as anthropogenic noise dominates soundscapes, and this type of noise pollution or disturbance has a negative impact on a wide range of organisms. The preservation of natural soundscapes is now a recognized conservation goal.
Source: Wikipedia links referenced above.