The potential for climate change due to increased greenhouse gas concentrations in the atmosphere is quite high and transport through ports and port operations are contributors. Additionally, stricter air quality standards and concern for nearby residents prompt port authorities to take stricter measures to improve air quality in their ports.

The world’s key ports have committed themselves to reduce greenhouse gas emissions (GHG) while continuing their role as transportation and economic centres. This commitment is called the World Ports Climate Initiative (WPCI). The ports do this through influencing the sustainability of supply chains, taking into account local circumstances and varying port management structures. The ports actively seek the cooperation of ships in support of measures to reduce emissions to air from ships.

One of the projects within WPCI is the Environmental Ship Index (ESI). The Environmental Ship Index (ESI) identifies seagoing ships that perform better in reducing air emissions than required by the current emission standards of the International Maritime Organization.

The ESI evaluates the amount of nitrogen oxide (NOx) and sulphur oxide (SOx) that is emitted by a ship; it includes a reporting scheme on the greenhouse gas emission of the ship. The ESI is a perfect indicator of the environmental performance of ocean going vessels and will assist in identifying cleaner ships in a general way.

The index is intended to be used by ports to reward ships when they participate in the ESI and will promote clean ships, but can also be used by shippers and ship owners as their own promotional instrument. It should be noted that while the ESI database will provide a total score, the rewards can either be based on that total or on each of its constituent parts separately; for that purpose those parts are appearing in the ship details.

ESI is completely voluntary and WPCI hopes that the global port community will assume its role in improving the maritime and port environment. Finally all stakeholders in maritime transport can use the ESI as a means to improve their environmental performance and as an instrument to reach their sustainability goals (see figure).

With regard to the further development of the ESI, the following should be noted. The ESI is a flexible instrument that may be adapted having due regard of the principles underlying IMO’s approach of the regulatory framework for the protection of the marine environment and also taking into account the priorities of ports with regard to the environmental performance of ships that ports wish to promote. This may mean that the weighing of the scores between the different constituents of the formula might change from port to port and that the evaluation of the performance can be adjusted to be more in line with experiences gained and technological developments. Additionally new constituents may be added and existing ones deleted; discussions with stakeholders that have an interest in ESI, form part of this process. Deletions will be made if a measure has proven to be effective and the behavioural change has become widespread. However to maintain the predictability of the ESI score and the program stability, changes will be few and never take place more than once a year.


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