Geneva:The World Meteorological Organisation (WMO) on Thursday warned global temperatures for the first six months of this year shattered more records, meaning 2016 is on track to be the world's hottest year on record. WMO noted June marked the 14th consecutive month of record heat for land and oceans and the 378th consecutive month with temperatures above the 20th century average. The last month with temperatures below the 20th-century average was December 1984, Xinhua reported. "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 Nino," WMO Secretary-General Petteri Taalas was quoted as saying. "The El Nino event, which turned up the Earth's thermostat, has now disappeared. Climate change, caused by heat-trapping greenhouse gases, will not. This means we face more heatwaves, more extreme rainfall and potential for higher impact tropical cyclones," Taalas added. Meanwhile, carbon dioxide concentrations have passed the symbolic milestone of 400 parts per million (ppm) in the atmosphere so far this year. Carbon dioxide levels vary according to the season, but the underlying trend is upwards. They showed a surprising increase for the first half of 2016, rising in June 2016 to nearly 407 ppm, four ppm greater than in June 2015. United Nations Secretary-General Ban Ki-moon has invited leaders to a special event on September 21 to deposit their instruments of ratification, acceptance, approval or accession to the Paris Agreement on climate change. It will also provide an opportunity for other countries to publicly commit to the agreement before the end of 2016.