MARPOL Annex VI: a maritime opportunity Mexico can't ignore

Mexico's maritime trade is already operating under many of the rules of the global shipping transition. What Mexico has not yet done is fully align with them and capture the health and commercial benefits that alignment could bring.

The visit to Mexico by International Maritime Organization Secretary-General Arsenio Dominguez comes at a consequential moment. Mexico is modernizing its ports and positioning itself for new marine fuels. Yet, it remains outside MARPOL Annex VI, the IMO framework governing air pollution, energy efficiency and greenhouse gas emissions from ships.

Four days before his arrival, the Institute of the Americas convened federal agencies, PEMEX, the maritime industry, academia and civil society. Three studies on emissions, health and economic impacts; regulatory gaps; and fuels, trade and competitiveness, point toward the same conclusion: Mexico does not face a choice between environmental ambition and competitiveness. It faces a choice between managing a transition already underway or allowing external markets and regulations to manage it for Mexico.

Mexico is already in the transition

More than 81% of Mexican port cargo is international. Vessels trading with the United States and Canada already enter the North American Emission Control Area, while European routes increasingly face stricter sulfur and greenhouse-gas requirements. Remaining outside Annex VI therefore does not shield Mexican trade from international standards.

Of the 12,449 vessels using Mexico's Exclusive Economic Zone in the 2024 modeling year, 53% crossed Mexican waters without calling at a Mexican port, while only around 5% flew the Mexican flag.

Applying Annex VI would reduce sulfur oxide emissions in Mexican waters by about 39% and could prevent roughly 100 premature deaths every year.

The economic adjustment is remarkably small. The modeled annual fuel bill for vessels operating in Mexican waters increases by approximately US$66 million, or about 1.5%, under accession. Around 85.5% of vessels would face no additional fuel cost because they already use compliant fuels or approved equivalent technologies. At the cargo level, the impact is roughly US$12-38 per container. Importantly, the US$66 million is not a bill for the Mexican government or PEMEX; it is an aggregate modeled change in vessel fuel costs.

Compliance does not require rebuilding Mexico's refineries

Annex VI accession should not be held hostage to modernization of Mexico's entire refining system.

Mexico already has many of the necessary building blocks: compliant marine diesel, lower-sulfur domestic production, import channels, specialized suppliers and inspection capabilities. The challenge is to connect them through fuel specifications, bunker delivery notes, testing, traceability and enforcement.

Selective refinery modernization should continue where PEMEX's broader downstream economics justify it. But maritime fuel demand is too small to justify a system-wide refining transformation on its own. Mexico can therefore move on Annex VI without waiting for every refinery project to be completed.

For PEMEX, the bigger question is market share

PEMEX already serves an established marine-diesel market. Diesel represents roughly 83% of maritime-sector energy use, and Mexico's marine-diesel sulfur specification is already below the Annex VI global ceiling.

The additional opportunity lies in compliant residual fuels and related services. The study identifies approximately 46,000 to 101,000 tons per year of potentially affected residual-fuel demand, small relative to PEMEX's overall operations, but commercially meaningful enough to support procurement, blending, storage, certification, distribution and bunkering at major ports.

Historical fuel-price spreads put the gross value differential associated with this volume in the tens of millions of dollars annually. This is not an estimate of PEMEX revenue or profit, but it shows that the opportunity is commercially identifiable.

The greater risk of doing nothing is not that container ships stop calling at Mexican ports. It is that they continue calling while purchasing their fuel in Houston, Panama or Los Angeles-Long Beach. Mexico could retain the cargo movement while losing bunker sales, maritime services and investment.

Accede to Annex VI, and start preparing the ECA now

Mexico has a favorable institutional window. Much of the necessary legal architecture already exists, and implementation can rely heavily on secondary regulation. The ongoing revision of NOM-016 offers an immediate opportunity to incorporate marine-fuel sulfur standards and sampling requirements. SRE can lead the treaty process, while an existing inter-departmental commission, like CIDEMAR, can coordinate the responsible institutions.

At the same time, Mexico should begin preparing the technical case for a Mexican Emission Control Area. Accession and ECA designation are separate decisions, but they need not be projects separated by years.

A Mexican ECA could create regulatory continuity with the North American ECA and deliver substantially larger benefits. The modeled scenario reduces SOx emissions by approximately 80%, PM2.5 and black carbon by 47%, and NOx by about 13%. It could also avoid as many as 292 premature deaths and nearly 6,900 years of life lost annually.

An ECA has a materially different cost profile. Its modeled increase in fleet fuel costs is approximately US$1.12 billion annually because it requires more stringent fuel standards across a much larger share of vessel activity. That is why it should be evaluated independently and designed carefully. But precisely because it requires more preparation, Mexico should start that work now.

From regulatory lag to competitive advantage

Mexico has two oceans, major international gateways, an incumbent national fuel supplier and the potential to become a platform for cleaner, and eventually low-carbon marine fuels serving North America, Central America and the Caribbean.

Remaining outside Annex VI does not preserve the status quo. It means continuing to face standards determined elsewhere, foregoing near-term public health benefits and risking the migration of marine-fuel sales and services to competing ports.

Accession offers a regulatory platform from which Mexico can strengthen its bunker market, create opportunities for PEMEX and private suppliers, improve environmental performance and prepare for the next generation of maritime fuels.

Secretary-General Dominguez's visit provides an unusually timely opportunity to turn that analysis into policy. Mexico should accede to MARPOL Annex VI, establish the minimum compliance architecture, develop a competitive domestic marine-fuel market and begin preparing its ECA proposal.

The opportunity is already there. Mexico can no longer afford to ignore it.

This article is also published on Mexico Business News. illuminem Voices is a democratic space presenting the opinions of leading Sustainability Thought Leaders, their views do not necessarily represent those of illuminem.

The world needs sustainability knowledge. At illuminem, no interest group or shareholder can influence our work. Thank you for supporting our mission to make high-quality and independent sustainability information free for all. Every contribution helps. Thank you for donating today.