A COALITION of 19 countries including Britain and the United States has agreed to create zero emissions shipping trade routes between ports to speed up the decarbonisation of the global maritime industry, officials involved said.

The shipping industry, which transports about 90 per cent of world trade, accounts for nearly 3 per cent of the world's CO2 emissions.

UN shipping agency the International Maritime Organization (IMO) has said it aims to reduce overall greenhouse gas emissions from ships by 50 per cent from 2008 levels by 2050. The goal is not aligned with the 2015 Paris Agreement on climate change and the sector is under pressure to be more ambitious.

The signatory countries involved in the 'Clydebank Declaration', which was launched at the recent COP26 climate summit in Glasgow, agreed to support the establishment of at least six green corridors by 2025, which will require developing supplies of zero emissions fuels, the infrastructure required for decarbonisation and regulatory frameworks.

"It is our aspiration to see many more corridors in operation by 2030," their mission statement said.

Britain's maritime minister Robert Courts said countries alone would not be able to decarbonise shipping routes without the commitment of private and non-governmental sectors.

US Transportation Secretary Pete Buttigieg said the declaration was "a big step forward for green shipping corridors and collective action".

The IMO's Secretary General Kitack Lim said: "We must upgrade our ambition, keeping up with the latest developments in the global community".

It was unclear how the green corridor commitments would get to zero shipping emissions.

Madeline Rose, with green group Pacific Environment, said "the Clydebank framework leaves room for delay tactics and fossil fuel loopholes".

"We urge partner countries and ports to act quickly to set immediate, interim and ultimately mandatory benchmarks to phase out all fossil fuel ship pollution along their shared corridors," Ms Rose said.

Other signatory countries are Australia, Belgium, Canada, Chile, Costa Rica, Denmark, Fiji, Finland, France, Germany, Republic of Ireland, Japan, Marshall Islands, Netherlands, New Zealand, Norway and Sweden.