Zero Emission Maritime Buyers Alliance (ZEMBA)

Nearly every product that fills our homes and shops has crossed an ocean, carried by ships running on some of the dirtiest fuel on the planet. Shipping moves over 80% of global trade, producing around 3% of global greenhouse gas emissions and adding to ocean acidification and air pollution.

This isn’t for lack of solutions. Cutting shipping emissions is possible today, but investment has stayed limited without guaranteed long-term demand to justify the switch.

Zero-emission fuels can cost two to five times more than conventional marine fuel, and no shipowner wants to gamble on changing how they power their vessels without guaranteed customers.

Without that certainty, shipping emissions are projected to keep rising as trade grows, even as the world needs them to fall by 20% from 2008 levels by 2030.

The Zero Emission Maritime Buyers Alliance (ZEMBA) is a buyers’ alliance that pools the purchasing power of nearly 50 of the world’s most influential cargo owners, including Amazon, IKEA and Nike, turning their combined demand into binding, multi-year contracts for zero-emission shipping.

Rather than waiting for policy or regulation, ZEMBA runs competitive procurement tenders where members commit upfront to buy zero-emission shipping. That gives shipping companies the confidence to invest in low-emission vessels and new fuel supply chains, spreading cost and risk across the alliance.

Co-founded in 2023 by the Aspen Institute Energy and Environment Program, ZEMBA is now an initiative of the Center for Green Market Activation (GMA). Its first two tenders are expected to cut at least 200,000 metric tonnes of CO2e in container shipping between 2026 and 2031, with a third tender launch targeted for 2027.

By pooling demand and driving down the cost premium on zero-emission fuels, ZEMBA is helping push shipping towards a positive tipping point, the threshold beyond which change becomes self-propelling, aiming to drive zero-emission fuels to a 5-10% share of the global maritime energy mix, the point where clean shipping becomes the standard, not the exception.

As a Finalist, The Earthshot Prize will help ZEMBA connect with more cargo owners, shipping companies, fuel producers, investors and policymakers, and raise awareness of its collaborative approach to maritime decarbonisation.