The advisory opinion has helpfully clarified States’ obligations in respect of all sources of GHG emissions under UNCLOS. These are stringent obligations, and simply complying with the Paris Agreement or partaking in International Maritime Organization (IMO) or International Civil Aviation Organization (ICAO) initiatives is unlikely to be enough. The measures States need to take must be determined objectively, by reference to the best available science and a 1.5°C pathway. Whilst international efforts remain short of that standard, States need to take unilateral or regional action to meet their international legal obligations.  

This is particularly important for the international shipping and aviation sectors, where States have traditionally deferred to the IMO and ICAO respectively. To the extent the rules adopted under those United Nations agencies remain unaligned with 1.5°C, States need to take further domestic and/or regional action if they are to be confident that they have met their legal obligations and are not exposed to international responsibility for breaches of such obligations. 

The briefing sets out: 

• Recommendations for policymakers relating to the aviation and shipping sectors;  

• A summary of the key legal findings of the advisory opinion; and 

• A detailed legal analysis of the advisory opinion and its implications for the international shipping and aviation sectors.