CLIMATE & SECURITYNew Study Suggests Climate Change Will Make Submarine Warfare More Complex
Over the coming decades, soundwaves will travel further through a warmer, chemically different, less dense ocean—and it will be noisier underwater than ever. With sound traveling further, undersea stealth platforms such as submarines will find it more difficult to hide in the open ocean. But they may also find it easier to hide in coastal waters, as the ocean becomes noisier.
The AUKUS pact promises to provide Australia with the first of its nuclear-powered submarines (SSNs) in the 2030s. But how will those boats, and the AUKUS SSNs to be delivered in the 2040s, fare in oceans whose soundscapes have been altered by ocean acidification and climate change?
A new study suggests that over the coming decades, soundwaves will travel further through a warmer, chemically different, less dense ocean—and it will be noisier underwater than ever.
Australia learned long ago that acquiring submarines is complex and always takes longer than expected. This was certainly the case with the Oberon class that Australia purchased from Britain in the 1960s—eight were ordered but only six delivered. And it held true for the Collins class that followed, which had problems that took almost 20 years to remediate.
Lengthy submarine design and delivery schedules create opportunities for adversaries to capitalize on fast-moving disruptive technologies such as artificial intelligence, quantum computing and autonomous systems. These technologies will change how underwater operations are conducted in ways that are difficult to predict and account for.
However, it is possible to predict with some confidence the ways in which the acoustic environment will change over the coming decades—and my simulator does just that. My research suggests that as the oceans become warmer and their chemical make-up changes, sound will travel further due to reduced transmission loss.
By 2100, ultrasonic sonar transmissions in the 30 kilohertz range (a frequency that might be used for mine hunting) will travel between 40% and 87% further than they do today, and sonar transmissions in the 10 kilohertz range (a frequency appropriate for hydrographic mapping) will travel between 15% and 25% further.
The effect will vary depending on latitude: colder polar oceans will experience more extreme variations than warmer coastal waters.
With sound traveling further, undersea stealth platforms such as submarines will find it more difficult to hide in the open ocean. But they may also find it easier to hide in coastal waters, as the ocean becomes noisier.
I modelled the effects of our changing oceans over time by bringing together predictions from the UN Intergovernmental Panel on Climate Change’s representative concentration pathway 8.5 climate model with data from ocean-going Argo data-collection robots that agencies such as the CSIRO use to monitor ocean parameters. I fed this data into a custom-built simulator, which generates a digital twin of the ocean to explore what these changes might look like.
