The urgent case for stronger climate targets for international shipping

International shipping is overwhelmingly reliant on fossil fuels, with annual carbon dioxide emissions equivalent to a country the size of Germany. Actions to reduce its emissions are therefore an important element of global efforts to combat climate change. This article re-assesses the international shipping sector’s initial greenhouse gas emissions reduction targets against the Paris Agreement goals. The analysis is based upon the latest data from the Intergovernmental Panel on Climate Change (IPCC) and International Maritime Organization (IMO) and uses the concept of carbon budgets to evaluate proportionate 1.5°C emissions pathways for the sector. The consequences of the resulting Paris-compliant pathways for shipping’s existing mitigation targets and strategy are discussed. The article concludes that significantly stronger short- and longer-term targets need to be set for the sector to be compatible with the Paris Agreement’s goals: 34% reductions on 2008 emissions levels by 2030, and zero emissions before 2050, compared with the sector’s existing target of a 50% cut in CO2 by 2050. Crucially, strengthening the target by the IMO’s strategy revision date of 2023 is imperative. The long asset lifetimes of ships and shipping infrastructure limit the speed of transition such that a delay of even a few years will dictate an untenable rate of decarbonization and increased risk of pushing the already challenging Paris goals out of reach. Key policy insightsThere is a gap between targets set out in the IMO’s Initial Strategy and what is needed by the shipping sector to be Paris-compliant.Paris-compliant targets require a 34% reduction in emissions by 2030, with zero emissions before 2050. Existing targets imply no absolute reduction in emissions to 2030, and only a 50% reduction by 2050.The longer the delay in setting new targets, the steeper subsequent decarbonization trajectories become. Delay beyond 2023 would necessitate an untenably rapid transition, given long shipping asset lifetimes and global requirements for new land-side infrastructures, increasing the mitigation burden on other sectors.COP26 in November 2021 is an opportunity for the shipping sector to signal its intent to strengthen its targets, and to implement this in its 2023 strategy revision process, at the latest. There is a gap between targets set out in the IMO’s Initial Strategy and what is needed by the shipping sector to be Paris-compliant. Paris-compliant targets require a 34% reduction in emissions by 2030, with zero emissions before 2050. Existing targets imply no absolute reduction in emissions to 2030, and only a 50% reduction by 2050. The longer the delay in setting new targets, the steeper subsequent decarbonization trajectories become. Delay beyond 2023 would necessitate an untenably rapid transition, given long shipping asset lifetimes and global requirements for new land-side infrastructures, increasing the mitigation burden on other sectors. COP26 in November 2021 is an opportunity for the shipping sector to signal its intent to strengthen its targets, and to implement this in its 2023 strategy revision process, at the latest.

国际航运业极度依赖化石燃料，其年度二氧化碳排放量相当于德国一国的排放总量。因此，降低航运碳排放的行动是全球应对气候变化努力的重要组成部分。
本文对照《巴黎协定》(Paris Agreement)目标，重新评估了国际航运业最初设定的温室气体减排目标。本分析依托政府间气候变化专门委员会(Intergovernmental Panel on Climate Change，IPCC)与国际海事组织(International Maritime Organization，IMO)的最新数据，采用碳预算(carbon budget)概念，评估该行业符合1.5℃温控目标的合理排放路径。本文还探讨了符合《巴黎协定》要求的排放路径对航运业现有减排目标与战略的影响。
本文得出结论：为使航运业契合《巴黎协定》目标，必须设定力度显著更大的短期与长期减排目标——相较于该行业现行的2050年二氧化碳减排50%的目标，新目标应实现2030年较2008年排放水平降低34%，并于2050年前实现零排放。至关重要的是，必须在国际海事组织2023年战略修订节点前完成减排目标的强化工作。船舶及航运基础设施的较长资产使用寿命限制了转型速度，即便仅延迟数年，也将导致脱碳速率难以承受，并进一步加大使本已艰巨的《巴黎协定》目标无法达成的风险。
核心政策启示：
1. 国际海事组织初始战略中设定的目标，与航运业实现《巴黎协定》合规所需的目标存在差距。
2. 符合《巴黎协定》要求的减排目标需在2030年前实现排放降低34%，并于2050年前实现零排放；而现行目标仅要求至2030年实现绝对排放量无下降，且仅承诺2050年减排50%。
3. 新减排目标的设定延迟越久，后续脱碳路径的陡峭程度就越高。考虑到航运资产使用寿命较长、全球需新建陆上配套基础设施，若延迟至2023年之后再调整目标，将不得不以难以承受的速度推进转型，同时加重其他行业的减排负担。
4. 2021年11月召开的第26届联合国气候变化大会(COP26)是航运业传递强化减排目标意愿的契机，且最晚应在2023年战略修订进程中落实相关调整。