Bunkering for change: Knowledge preparedness on the environmental aspect of ammonia as a marine fuel

Nitrogen cycling is essential to ecosystem functioning and the overall health of our planet. Ammonia, a nitrogen-containing product, as well as a nutrient, is promoted as a low-carbon fuel for the maritime sector, with spectacular production increase in plan. Similar to any other widespread fuels in the past, it is paramount to be prepared for the potential environmental impact of ammonia fuel. Here, through our preliminary calculations using literature data, we suggest that the amount of ammonia to be produced to fulfil the maritime energy need by 2050 may entail large alterations in global nitrogen cycling. Currently, the literature based on limited known cases of ammonia excess is insufficient to quantify the environmental impacts caused by the probable increase in bunkering ammonia release at global scale. With a few knowledge gaps identified, we call on the marine science community to investigate the potential environmental impact related to substantial ammonia excess, contributing new knowledge to a more environmentally sustainable future.