Many countries agree – in theory at least – to align shipping emissions with the Paris Agreement. The “Tony de Brum” declaration, issued last December and signed by 44 countries, calls on the maritime sector to take “urgent measures” to help achieve the 2C and 1.5C targets in Paris. The great unknown in global shipping is the influence and influence of the new U.S. presidential team. This will have a significant impact over the next few years in the global shipping sector. Assuming a zero-carbon-fuel date by 2030, the introduction of additional measures, such as lower speeds, fuel mixing and operational and technical efficiency, based on the mediated assumptions of the literature, could reduce emissions to 1652 MtCO2, or a 50% carbon budget of 1.5oC. There are a wide range of options to reduce CO2 emissions from shipping . A review of the literature of Bouman et al.  summarizes some of these options into five categories, see Table 1.
The full text of IMO`s initial strategy to reduce ship`s greenhouse gas emissions can be found in the Talanoa Dialogue here. Japan has proposed reducing emissions to 50% below 2008 levels by 2060 and improving ship energy efficiency by 40% by 2030. Japan also includes the idea of “changes” to the target until a subsequent accessibility audit is carried out by the IMO. Ships typically emit less carbon dioxide (CO2) per tonne of cargo than trucks or airplanes. But the global impact of shipping remains enormous: if it is a country, it would be the sixth-highest emitter in the world. So what should we do? While there are measures that could reduce the basic emissions promised by existing vessels, there are also emission commitments for future vessels. This section sets indicative values for the size of these additional related emissions. The new vessels will be divided into two types: replacement vessels for existing vessels when they are scrapped and “additional” vessels reflecting the overall growth of the vessel trade. To date, studies of promised emissions have been the subject of in-depth analysis [20,21,22] or high-level global analyses, of which shipping is one of many sectors considered to be one of the many sectors [12, 13, 23]. To estimate transit emissions, the global coverage documents have adopted other assumptions in the transportation sector.
Smith et al.  assume that the lifespan of the assets for ships is similar to that of aviation, and Tong et al.  use the assumptions of Davis et al.