The first six months of this year have continued to shatter global heat records, putting 2016 on track to be the Earths hottest year on record, the World Meteorological Organisation said on Thursday.

The United Nations-linked body said in a report that June 2016 was the 14th consecutive month of record heat around the planet and the 378th consecutive month with temperatures above the 20th Century average.

The organisation said that global warming causing carbon dioxide concentrations, so far this year, have surpassed the symbolic milestone of 400 parts per million in the atmosphere.

Another month, another record. And another. And another. Decades-long trends of climate change are reaching new climaxes, fuelled by the strong 2015/2016 El Niño, said World Meteorological Organisation Secretary-General Petteri Taalas said in a statement.

This underlines more starkly than ever the need to approve and implement the Paris Agreement on climate change.

The report found that heat has resulted in very early onset of seasonal melting of major ice sheets with Arctic Sea ice now covering about 40 per cent less area during the summer melt season than it did in the 1970s.