How can the maritime sector find a path to net zero?

With around 80% of the world’s trade being transported by ship, the decarbonization of the maritime industry has never been more urgent. Yet there is no single route to net-zero emissions but, rather, multiple pathways, each with its own challenges and trade-offs. In this insight, we explore the industry’s objectives, the different pathways to achieve them and what they’ll mean for the future of the shipping industry.

Defining targets and a carbon budget

It is first essential to highlight that climate change is the result of the total quantity of greenhouse gases (GHGs) in the atmosphere, rather than just those emitted at any given point. This makes immediate action vital.

A carbon budget, as defined by the Intergovernmental Panel on Climate Change (IPCC), sets the total amount of CO₂ humanity can emit to remain below a given global warming target. According to the IPCC’s 6^th Assessment Report, maintaining a +1.5°C trajectory with a 50% probability allows for a carbon budget of 500 gigatons of CO₂ (GtCO₂) for all human activity from 2020 onward. This budget is a key factor in shaping decarbonization pathways across industries, including shipping.

For the maritime industry, limiting emissions is crucial to minimizing its contribution to the rise of global temperatures and mitigating climate change impacts. The International Maritime Organization (IMO) does not currently use a carbon budget as part of its GHG strategy. Rather, it sets specific GHG emissions targets for 2030, 2040 and 2050. It also expands the scope to include “well-to-tank” emissions – that is, those generated across the supply chain and fuel production process. 

A clear understanding of carbon budgets allows us to define realistic decarbonization trajectories and forecast the impacts of different actions on meeting climate goals. 

Taking a bottom-up approach

Tackling the challenge of decarbonization requires a comprehensive understanding of the scale and complexity of the situation. 

To help bridge this gap, BV has developed a granular, science-based model that adopts a bottom-up approach to project maritime GHG emissions up to 2050. 

Developing this model included several key steps, such as categorizing the fleet by ship type; projecting future efficiency gains; assessing the evolving fuel mix; and calculating the number of vessels required to meet projected transport demand.

The resulting methodology provides an overview of potential emission trajectories and the effectiveness of different decarbonization strategies.
 

Five scenarios for the future of shipping

BV’s bottom-up approach explores five possible decarbonization scenarios: 

• 1 – Business as Usual
  
  Shipping demand continues to grow rapidly, but operational practices remain largely unchanged.
  
  Adoption of alternative fuels and energy-efficiency measures is limited.

• 2a – Central Progressive
  
  Transport demand grows moderately.
  
  There is a strong shift to low-carbon fuels and enhanced technical and operational measures.

• 2b – Central Conservative
  
  Transport demand grows moderately.
  
  High costs and limited supply hinder the transition to renewable and low-carbon fuels, making decarbonization slower than in the Central Progressive (2a) scenario.

• 3 – 2030 Crest
  
  There is a peak in transport demand around 2030, followed by a decline due to reshoring, geopolitical shifts and evolving consumer habits.
  
  There is still a strong shift to low-carbon fuels and enhanced technical and operational measures.

• 4 – The Technological Fix
  
  Transport work grows moderately.
  
  Technological breakthroughs in production enable the rapid adoption of renewable and low-carbon fuels. 

What do these scenarios mean?

The transport demand outlook varies significantly across the five scenarios. In scenario 1 (Business as Usual), transport work grows by more than 110% between 2018 and 2050. Meanwhile, the Central Progressive, Central Conservative and Technological Fix scenarios project a more moderate increase (53%). The 2030 Crest scenario stands apart, with a predicted decline of more than 30% in transport work after 2030.

A growth in transport demand, logically leads to an increase in fleet size. The number of vessels in the global fleet grows by 43% by 2050 in scenarios 2a, 2b and 4. In the 2030 Crest scenario, however, it shrinks by nearly 40%. 

Fleet speed declines by almost 30% in all scenarios – except the Business as Usual scenario – and average waiting times are reduced by 50%, optimizing fleet capacity. Bulk carriers see substantial growth of 63% in most scenarios, and oil tankers experience the biggest decline, with nearly 75% fewer vessels in operation by 2050, except in the Business as Usual scenario. This difference in the growth trends in different segments is due to the fact that our model is based on the IEA’s net zero scenario. This indicates a large decrease in fossil fuel transportation, and a large increase in both new fuel transportation and GDP related sectors.

The state of the industry’s transition is also reflected on fuel consumption trends, with fuel demand decreasing between 2020 and 2030 in all scenarios. The Central Progressive scenario sees an initial shift toward biofuels but, post-2040-45, e-fuels gain in market share as a dominant energy source.

As transport work varies in three of the five modeled scenarios, in turn projected GHG emissions vary. The Business as Usual scenario is the only pathway in which emissions continue to rise. All other scenarios project a 70-90% reduction by 2050, when compared to 2008 levels. The 2030 Crest and Technological Fix are predicted to achieve the lowest emissions. While most scenarios meet the IMO’s 2030 targets, only these two align with its long-term 2040 and 2050 goals.
 

Based on these scenarios, achieving net zero by 2050 requires either reduced transport demand or a significant increase in alternative fuels. However, operational and energy efficiency measures can also significantly cut emissions.

Bureau Veritas is helping the maritime industry chart a path to net zero

Bureau Veritas is supporting the industry’s decarbonization journey by helping navigate new and existing challenges, and identifying actionable pathways to net zero. Our tailored solutions include assisting shipowners, charterers and financers in the definition of decarbonization trajectories at both asset and company level, verifying the amount of GHG emissions emitted by a company, and working together with banks, investment funds and financial companies to decarbonize investment portfolios. 

 

The path to decarbonization is not a singular route nor a one-size-fits-all journey but, rather, a spectrum of opportunities and challenges. Understanding the implications of different decarbonization pathways is essential for informed decision-making. 

Read more about the pathways to net zero in our Decarbonization Trajectories report here.