Members of the International Maritime Organization (IMO) for the first time have agreed on a plan to cut its emissions of greenhouse gases.

Tough negotiations at last week's IMO meeting in London produced an agreement to reduce emissions by 50 percent by 2050 compared to 2008 levels.  Over the next five years, negotiators are to develop a package of measures to fulfil the target, delivering a final strategy in 2023.

The United States, Saudi Arabia, Brazil and a few other countries opposed the mandate.  The European Union, Britain, and several small island states had wanted emissions cuts of up to 70 to 100 percent.  Climate campaigners say the agreed-on compromise doesn't go far enough to comply with the global warming limits in the Paris Agreement.

"Nevertheless, this deal provides the very clear policy signal that is needed for international shipping to begin to play its full part to achieve the goals of the Paris Agreement," read the joint statement released by Marshall Islands environment minister David Paul and Christiana Figueres, head of the Mission 2020 initiative on climate action.