This year is on course to be the fourth hottest year on record, trailing only the three previous years, as rising levels of greenhouse gases warm the planet, the World Meteorological Organisation said.

Up to October 31, mean temperatures in 2018 were an estimated 0.98 warmer than the average for 1850-1900, according the UN agency's provisional State of the Global Climate report.

This year is on course to be the fourth hottest year on record, trailing only the three previous years, as rising levels of greenhouse gases warm the planet, the World Meteorological Organisation said.

“We are not on track to meet climate change targets and rein in temperature increases,” said Petteri Taalas, WMO Secretary-General. “Greenhouse gas concentrations are once again at record levels and if the current trend continues we may see temperature increases 3 to 5 degrees by the end of the century."

The WMO report comes days ahead of a global climate summit in Katowice, Poland, where nations will discuss progress on implementing the goals of the Paris climate accord signed three years ago keep temperatures to 1.5-2 degrees above pre-industrial levels. Australia's delegation will be led by Environment Minister Melissa Price.

Firefighters work on a wildfire on Winter Hill near Bolton, England. Extreme temperatures, particularly warm ones, have again been prominent in 2018, on course to be one of the hottest years in history. PA via AP

2016 remains the hottest year on record, propelled higher by a big El Nino event that began the previous year. The 20 warmest years have all occurred within the past 22, the WMO said.

Warming oceans

While surface temperatures catch much of the attention, the build-up of heat in the oceans may offer a clearer guide to the long-term warming trend.

More than 90 per cent of the extra heat trapped by greenhouse gases ends up in the oceans, and each three-month period in 2018 up to September were either the hottest or second hottest on record for the upper 700 metres and 2000 metres.

"In each case, where 2018 was second highest, the highest was recorded in 2017," the WMO report said.

Sea level rise data, another gauge of warming, shows the rise for the January to July period of this year to be about 2 to 3 millimetres compared with a year earlier, it said.

For Australia, mean temperatures for the first 10 month of the year were the fifth-highest in records going back to 1910, the Bureau of Meteorology said.