Why a longer shipping route can cost more even when cargo volumes barely rise
UN Trade and Development’s maritime review shows what distance adds to the picture.
The amount of cargo loaded is only one measure of demand for ships. UN Trade and Development reported that seaborne trade volume rose 2.2 percent in 2024 while ton-miles, which account for the distance each tonne travels, increased by about 6 percent.
The difference reflects the effect of rerouting. If a vessel carries the same cargo on a longer voyage, the tonnage is unchanged, but the trip uses more sailing time and can require more fuel.
The agency's September 2025 review projected just 0.5 percent growth in maritime trade volume for that year. Its distance measure explains why slow growth in tonnes can still leave shipping schedules and costs under pressure.