Are the IMO's new targets for international shipping compatible with the Paris Climate Agreement?

International shipping is a major contributor to climate change. The International Maritime Organization (IMO) has jurisdiction over the sector's efforts to reduce greenhouse gas emissions, and in July 2023 agreed a revised climate change strategy, setting tightened targets for emissions reductions by 2030, 2040 and 2050. In this perspective article, we analyse the remaining carbon budgets available to the international shipping sector, to assess whether these new targets constitute a sufficient contribution to meeting the overarching Paris Agreement goal to limit global heating to 1.5 degrees C. The new strategy sets both 'indicative checkpoints' and more ambitious 'strive' targets. Both represent a major advance over the previous strategy, however, only the 'strive' targets are compatible with the 1.5 degrees C limit. The first 'strive' target is for 30% reductions by 2030, just seven years away. To meet this goal, it is imperative that the IMO, nation states and the shipping industry act immediately to accelerate deployment of known technologies and operational practices that improve energy efficiency and cut CO2 emissions in the existing fleet.