July was the warmest month ever on record worldwide and 2015 has been so far the hottest year, the US National Oceanic and Atmospheric Administration said on 20 August, just over three months to go before world leaders seek to reach a climate agreement in Paris.

In its monthly global climate report released online on Thursday, NOAA said many countries and the world's oceans experienced heatwaves, with the Earth's oceans temperature also hitting record highs last month.

This July was the all-time highest monthly temperature in the records that date back to 1880, at 16.61C, according to NOAA.

The first seven months of 2015 comprised the warmest such period on record globally at 0.85C above the 20th century average, it said.

The record comes after NOAA and the US space agency Nasa said in January that 2014 was the Earth's hottest on record, a fact used by the White House and the United Nations to make the case for immediate action to combat climate change.

One of the goals of the UN climate talks is to stop global temperatures from rising more than 2C above pre-industrial levels, which scientists say is the limit beyond which the world will suffer ever worsening floods, droughts, storms and rising seas. The NOAA says that the rapid rise is mainly attributable to humans burning fossil fuels.