US coal exports hit a record 13.6m short tons in March, which means higher employment for dry bulk carriers but raised concern among environmental campaigners opposed to the planet's most polluting fossil fuel. 

As US coal export soar, more than 100m short tons is likely to he exported in 2013, marking the third consecutive year of exports at this high level, the Energy Information Administration forecast. 

The trade has developed because the US relies less on its coal for electricity generation due to its abundance of cheap natural gas. 

Technical advances in drilling have released gas from shale rock deep underground. Carbon emissions have thus declined in the US because gas is half as polluting as coal. However, the flipside is that the US has plenty of coal to export and Asia and Europe are keen to take this cheap coal for power generation. A carbon tax to discourage countries importing and using coal is so low in Europe that it is not a deterrent. Green groups lament the rise in coal consumption in Europe and Asia. US coal exports were recently listed as one of the top threats to the climate by environmental organization Greenpeace in a report called Point of No Return.

The top five destinations of exported US coal, in descending order, during March were China, the Netherlands, the UK, South Korea and Brazil, said the BA. Panamaxes and supramaxes are used for this coal trade. 

The trade has yet to impact heavily on the overall dry bulk market, but it will contribute to an expected recovery in dry bulk in the next couple of years, said a sector analyst.