Possible future changes of ambient shipping noise at 0.1–1 kHz in the North Pacific caused by changing seawater chemistry conditions are analyzed with a simplified propagation model. Probable decreases of pH would cause meaningful reduction of the sound absorption coefficient in near-surface ocean water for these frequencies. The results show that a few decibels of increase may occur in 100 years in some very quiet areas very far from noise sources, with small effects closer to noise sources. The use of ray physics allows sound energy attenuated via volume absorption and by the seafloor to be compared.
Udovydchenkov, I.A., Duda, T.F., Doney, S.C., & Lima, I.D., 2010. Modeling deep ocean shipping noise in varying acidity conditions. Journal Acoustical Society of America Express Letters 128(3): EL130-EL136. Article (subscription required).