“The ocean has already absorbed 90% of the heat generated by and roughly 30% of the carbon dioxide emitted by humans burning fossil fuels. Warmer water also expands and raises sea levels as well as holds less oxygen. So, we’re seeing the ocean heat up, lose oxygen, and get bigger. A warming ocean will also supercharge storms,” director of climate science at NGO Ocean Conservancy, explained to Splash.
Ocean Conservancy’s shipping emissions campaign manager warned that vessel owners and operators face risks of delays in departures and entry to ports and more frequent rerouting with accompanying costs, as well as potential damage to their ships and risk to crews.
“Cargo owners’ risks include damage and loss of their cargo, costly delivery delays, and potentially higher demurrage and detention fees,” NGO Ocean Conservancy said.
Data Ocean Conservancy provided to Splash claims that the total climate risk linked to the impacts of extreme weather on ports could be worth up to $7.6bn each year. In addition to these direct costs, port closures and reconstruction due to storms and other climate hazards put an estimated $67bn of trade at risk annually.
The policy officer for shipping and climate at Seas at Risk alluded to recent research from Oxford University’s Environmental Change Institute which estimates that more than $122bn of economic activity including $81bn in international trade is at risk from the impact of extreme climate events per year. And since an estimated 90% of global trade is done via ships, it is no wonder that the figures are so high.
Furthermore, the rising sea levels due to high temperatures might require substantial work on raising the heights of port terminals. Ocean Conservancy noted that raising the height of existing port terminals alone could cost more than $63bn by the end of the century.
But shipping is also a contributing factor in all of this. Commercial shipping’s use of fossil fuels generates approximately 1bn metric tonnes of greenhouse gases (GHG) yearly, as well as black carbon and soot. Using wind propulsion, slow steaming, developing and deploying zero- and near-zero lifecycle emission alternative fuels will decrease shipping’s GHG emissions considerably.
There is another way maritime shipping is contributing to rising sea temperatures albeit filed under unintended consequences.
The global sulphur cap regulation imposed in 2020 by the International Maritime Organization (IMO) has cut ships’ sulphur pollution by more than 80% and improved air quality worldwide. The reduction has also lessened the effect of sulphate particles in seeding and brightening the distinctive low-lying, disappearing reflective clouds that follow in the wake of ships – so-called ship tracks – and help cool the planet.
The lack of ship tracks warmed the planet up faster and the trend is magnified in the Atlantic, where maritime traffic is particularly dense. In shipping corridors, the increased light represents a 50% boost to the warming effect of human carbon emissions. This was shown to be the case in a paper published last month by an atmospheric scientist at Florida State University.
Another way ships contribute to the increased production of GHG is through fouling, a process in which marine plants and animals attach themselves to ships’ hulls. This too is set to worsen as oceans get warmer.
Fouling can damage a ship, and increase drag, and its immediate effect is a loss in ship speed at a constant power – or a power increase to maintain a constant speed leading to increased emissions. The accumulated costs of hull fouling can amount to $30bn in business costs, plus millions of tons of CO2 annually, according to studies carried out by class society DNV.
Studies have revealed that a layer of slime as thin as 0.5 mm covering up to 50% of a hull surface can trigger an increase of GHG emissions in the range of 20 to 25%, depending on ship characteristics, speed and other prevailing conditions.
More severe biofouling conditions can lead to higher emissions. With a light layer of small calcareous growth like barnacles or tubeworms, an average-length container ship can see an increase in GHG emissions of up to 55%, dependent on ship characteristics and speed.
Crucially, the fouling problem gets worse for vessels idling in warmer waters. Also, with ocean temperatures rising on a global scale, biofouling hotspots are increasing in size and severity, leaving more ships at risk of the negative impacts of biofouling on ship efficiency, according to a recent study by I-Tech, a Swedish developer of antifouling products.
Since fouling species flourish in warmer waters, the risk of them making a home on ship hulls is significantly increasing year-on-year.
Trying to put some positive spin on the changed climate in conclusion, Weathernews told Splash: “The trendsetters should see an opportunity. With increased temperatures shipping passages north of Russia and Canada should become more frequent. This will lead to a vast improvement in emissions as voyages will be much shorter.”