The biggest ships are speeding up and emitting more. Photo: ©Corine van Kapel – Shutterstock.com
Greenhouse gas emissions from global shipping 2013–2015
A new report by the International Council on Clean Transportation (ICCT) that describes trends in global shipping activity and emissions for the years 2013 to 2015, found that emissions generally increased over this period, with efficiency improvements more than offset by increases in activity. Key findings include:
Fuel consumption is increasing. Total shipping fuel consumption increased from 291 to 298 million tonnes (+2.4%) from 2013 to 2015.
Shipping GHG emissions are increasing despite improvements in operational efficiency for many ship classes. Increasing emissions are being driven by rising demand for shipping and the associated consumption of fossil fuels.
After carbon dioxide (CO2), black carbon (BC) contributes the most to the climate impact of shipping, representing 7 per cent of total shipping CO2-eq emissions on a 100-year timescale and 21 per cent of CO2-eq emissions on a 20-year time scale.
Increases in efficiency have not reduced absolute CO2 emissions from ships. Although the CO2 intensity of many major ship classes decreased (i.e. they became more efficient) from 2013 to 2015, total CO2 emissions from ships increased. Thus, increases in distance travelled due to a greater demand for shipping more than offset gains in operational efficiency during the period studied.
The biggest ships are speeding up and emitting more. Whereas average ship cruising speeds remained largely unchanged between 2013 and 2015, the largest oil tankers and the largest container ships sped up and emitted more in 2015 than in 2013. If more ships follow suit and speed up, the CO2 efficiency of the maritime transport sector will degrade.
Absolute reductions in ship emissions will require concerted action to improve the energy efficiency of shipping and to develop and deploy alternative fuel and propulsion concepts. The only way to reduce emissions from ships without constraining demand is to substantially reduce the amount of greenhouse gases emitted per unit of transport supply.
Source: ICCT, 17 October 2017.