Cargo containers re-routed due to Houthi rebel attacks on Red Sea shipping, have added an average of 26% to existing CO2 emissions, an analysis by news agency Reuters has found.
The agency analysed emissions data for more than 6 000 individual cargo containers, shipped between 15 December 2023 and 31 March this year.
The average expected CO2 emission per container on the original shipping route through the Red Sea was expected to be 1,07 tons, but diversions, typically around Africa, have bumped up the average to 1,35 tons.
Information from international data and analytics outfit LSEG showed that a container ship sailing from Shanghai to Hamburg would emit 38% more CO2 if re-routed around Africa, instead of going through the Suez Canal.
ShipsGo, a container tracking platform, estimates that more than 600 vessels have been re-routed since the attacks began in October.
One of the individual voyages highlighted in the Reuters analysis included a voyage between Port Said in Egypt on the Mediterranean and Salalah in Oman, that would have taken eight days via the Suez Canal and the Red Sea, but took 30 days after diverting westwards through the Mediterranean, around Africa.
Another voyage, from the Nemrut Bay Port in the eastern Mediterranean and the Persian Gulf's Port Rashid in Dubai, which would have taken 15 days via the Suez Canal, was extended to 40 days due to the diversion.
A ship on a planned 22-day voyage between Hamburg, Germany and Jebel Ali, also in Dubai, ended up taking 60 days to reach its destination after it turned around two-thirds of the way through the Red Sea, and retraced its voyage through the Suez Canal and the Mediterranean before travelling south around Africa.
The Reuters study found that the longest delays affected ships heading to a port in the Mediterranean or in the Middle East, on either side of the Suez Canal. Delays for containers on longer journeys between Asia and North America tended to be less significant.