I was invited to write a guest post on the new IMO standards for the Mission Blue website.
The upshot is that the United Nations International Maritime Organization (IMO) adopted a set of noise guidelines that if followed by member nations could decrease low frequency shipping noise by 10dB (ten times less energy) in the next 30 years. This in effect could reverse 10dB increase in shipping noise that has occurred over the past few decades.
You can get the full post at Mission-Blue.org.