Next Monday, 23 September 2019, hundreds of government representatives, diplomats, representatives of multilateral agreements and organisations, the private sector and civil society will gather in New York on the occasion of the Climate Action Summit convened by UN Secretary-General António Guterres. Two days later, the Intergovernmental Panel on Climate Change (IPCC) will publish its eagerly awaited report on the impact of climate change on the oceans.

In the marine sector, governments are understandably focusing on the research and development of renewable energy sources. However, marine conservationists see another measure indispensable for climate protection: quieter oceans. This may at first sound weird, but is in fact very clear and also easy to achieve. Its contribution to reducing emissions would be significant. How come?

For marine animals, the perception of sound is vital. It serves orientation, communication, foraging, predator avoidance, mating and much more. However, at high intensities sound becomes noise, with all its negative impacts. These range from stress and displacement to DNA damage, malformations, a broad range of physical injuries and even death.

One source of noise that has doubled in some marine areas every decade since the 1950s is international cargo shipping, which also plays a considerable role in greenhouse gas emissions. The fact that this sector had been exempted from the goals of the Paris Climate Agreement entailed massive criticism. Later, however, states agreed at the International Maritime Organization (IMO) to reduce greenhouse gas emissions from cargo shipping by 50% until 2050 compared to 2008 as the baseline year. Now, how to achieve such a reduction? The approaches discussed include shifting to other fuels or implementing technical solutions in shipbuilding and energy efficiency. However, considering that cargo ships have a service life of around 30 years, the prospect that such measures could bring about rapid and substantial emission reduction is vanishing very quickly.

Less attention is paid to a management measure that is quite simple, but would immediately bring twofold benefit: reducing vessel speed. A recent publication (Leaper, 2019) calculates that reducing the speed of the global cargo shipping fleet by 10% at average would lead to a reduction in emissions of at least 13%. This already takes into account an increase in the number of ships to maintain the present cargo volumes. At the same time, this measure would also reduce noise pollution of the oceans by 40% and thus significantly relieve marine species and ecosystems.

Unimaginably loud: marine hydrocarbon exploration

Another activity is responsible for the loudest sound pulses generated by humans: seismics. When searching for oil and gas in the seabed, an exploration ship pulls arrays of up to 48 sonic cannons, which fire sound pulses of up to 260 decibels into the sea every 10 to 15 seconds for weeks or even months. For a long time, the effects of such noise sources haven’t been discussed in public at all or only related to sensitive cetacean species. However, in 2017 a study by Australian scientists shocked at least those people working in marine protection. A single sound cannon had killed all krill larvae and also a large part of the adult zooplankton at a distance of 1.2 kilometres in the entire study area. This devastates the very basis of the entire marine food web.

Negative effects, including the proven decline in fishing rates, caused by seismic activities can be easily avoided: by not carrying them out! This suggestion might initially raise the reaction: Well, this won’t happen in a day. Okay. But how fast can and should it go? Doesn’t the Paris Agreement provide for an end to fossil fuel use? However, there is still no phase-out strategy, neither internationally nor regionally. A look at the Mediterranean gives cause for concern, because the number of seismic explorations has risen sharply in recent years. While in 2005 this affected 3.8% of the Mediterranean Sea’s surface, the proportion had risen to 27% by 2013. Currently, Greece, Italy, Cyprus, Turkey, Montenegro and numerous other Mediterranean countries have issued licences for the use of sound cannons to search the sea bead for hydrocarbons. This is in plain contradiction to the Paris Agreement. While governments in New York talk about climate protection, at the same time sound cannons are fired in search for the black gold.

So the facts are simple. If we reduce underwater noise at two of its main sources, we significantly reduce both greenhouse gas emissions and negative impacts on marine biodiversity. Actually a win-win situation. What are we waiting for?

Nicolas Entrup

Nicolas Entrup

Ocean Policy Expert, OceanCare

Nicolas Entrup has been working for international marine conservation for more than 25 years. He is heading the programme of the marine conservation organisation OceanCare to reduce underwater noise pollution. At the invitation of the Belgian government, Nicolas Entrup will speak about “Making protecting the ocean a driver for climate action”at the “High Level Side Event on Climate and Oceans” to the UN Climate Action Summit on the 23rd of September. Speakers include the Belgian Minister of the North Sea Philippe de Backer, EU Commissioner for Maritime Affairs Karmenu Vella, the secretary general of the International Maritime Organization Kitack Lim, and the Marshall Islands Minister of Environment David Paul.