This review explores methanol as a marine fuel for reducing greenhouse gas (GHG) emissions in the shipping industry. Methanol, derived mainly from renewable sources and produced via carbon dioxide hydrogenation, is a promising alternative to traditional fuels like heavy fuel oil (HFO) and marine gas oil (MGO). It offers advantages such as lower sulfur content, high oxygen content, and compatibility with existing infrastructure, particularly liquefied natural gas (LNG) systems. Methanol is cost-effective, has a low carbon footprint, and can be used in existing marine engines with minimal modifications. It significantly reduces emissions of sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM), making it an environmentally friendly option. Methanol is also more flexible than LNG, as it does not require specialized pressure tanks. The review discusses the environmental and economic factors of methanol as a marine fuel, highlighting its potential to meet the International Maritime Organization's (IMO) goals of reducing GHG emissions by 50% by 2050. Methanol's production from renewable sources, such as solar and wind energy, and its ability to store carbon dioxide make it a sustainable option. However, challenges remain, including high production costs and the need for infrastructure development. The review also examines methanol's use in diesel engines, including direct mixing, port injection, and in-cylinder direct injection methods, which can reduce emissions and improve fuel efficiency. Methanol's production from carbon dioxide (e-methanol) is a promising approach for achieving carbon neutrality, as it can mitigate the greenhouse effect and produce clean fuels. The review concludes that methanol is a viable alternative to traditional marine fuels, offering environmental, economic, and operational benefits for the shipping industry.This review explores methanol as a marine fuel for reducing greenhouse gas (GHG) emissions in the shipping industry. Methanol, derived mainly from renewable sources and produced via carbon dioxide hydrogenation, is a promising alternative to traditional fuels like heavy fuel oil (HFO) and marine gas oil (MGO). It offers advantages such as lower sulfur content, high oxygen content, and compatibility with existing infrastructure, particularly liquefied natural gas (LNG) systems. Methanol is cost-effective, has a low carbon footprint, and can be used in existing marine engines with minimal modifications. It significantly reduces emissions of sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter (PM), making it an environmentally friendly option. Methanol is also more flexible than LNG, as it does not require specialized pressure tanks. The review discusses the environmental and economic factors of methanol as a marine fuel, highlighting its potential to meet the International Maritime Organization's (IMO) goals of reducing GHG emissions by 50% by 2050. Methanol's production from renewable sources, such as solar and wind energy, and its ability to store carbon dioxide make it a sustainable option. However, challenges remain, including high production costs and the need for infrastructure development. The review also examines methanol's use in diesel engines, including direct mixing, port injection, and in-cylinder direct injection methods, which can reduce emissions and improve fuel efficiency. Methanol's production from carbon dioxide (e-methanol) is a promising approach for achieving carbon neutrality, as it can mitigate the greenhouse effect and produce clean fuels. The review concludes that methanol is a viable alternative to traditional marine fuels, offering environmental, economic, and operational benefits for the shipping industry.