This endpoint returns CO2e emissions (i.e CO2 equivalent emissions) for the shortest path between a source port and a target port.

You can obtain accurate CO2 values for a specific vessel by passing its IMO as a query parameter. If we cannnot find enough data on the IMO you passed as a parameter, if you pass a wrong IMO number or if you pass no IMO, we estimate the CO2e emissions based on the trade lane (with 30 trade lanes supported) using the GLEC coefficients.

The response contains CO2e WTW (well-to-wheels) emissions in g for the shortest route between departure and arrival ports. We also provide detailed emissions with TTW (tank-to-wheels) emissions and WTT (well-to-tank) emissions. The method takes into account the emissions caused by the fuel consumption of the main engines, the auxiliary engines and the boilers.

The number of containers and the size of the containers can be precised. You can give a non integer number of containers that allows you to calculate CO2 for LCL. By default, we return emissions for one TEU.

If you don't know the number of containers, you can pass the weight and/or volume and the API will estimate the number of containers.

The `parameters`

field in the response contains all the parameters that were given in the request.

The `properties`

field in the response gives some data that was used to calculate the CO2 based on the parameters for example the distance, the distance in ECA zones, some data about the vessel, the trade lane, etc.

Note that the distance we use to calculate CO2e is 15% higher than the shortest distance (returned in the response) as recommended by the GLEC framework to take into account the stops in other ports, the weather and all other deviations from the shortest route.

The method used to calculate emissions is based on the following references :

- Third IMO Greenhouse Gas Study 2014;
- Fourth IMO Greenhouse Gas Study 2020;
- EMEP/EEA air pollutant emission inventory guidebook 2019;
- GLEC Framework 2020.