BRUSSELS, Sept 7 (Reuters) - Europe had its warmest summer on record this year, though only by a small margin over two previous highest temperatures for June-August, European Union scientists said on Tuesday. The EU"s Copernicus Climate Change Service said the average surface air temperature in June-August was close to 1.0C above the 1991-2020 average, making it the hottest in its dataset. The previous warmest summers, 2010 and 2018, were 0.1C cooler. The 2021 summer temperature marks the latest milestone in a long-term global warming trend as emissions of greenhouse gases change the planet"s climate. Copernicus" records go back to 1950 but are cross-checked with other data sets that trace back to the mid-19th century. It said in a statement that, globally, August 2021 was, together with August 2017, the third-warmest on record at a little over 0.3C warmer than the 1991-2020 average. For Europe, August 2021 was near the 1991-2020 average, but with contrasting conditions across the continent. These included record-breaking maximum temperatures in Mediterranean countries, warmer-than-average temperatures in the east and generally below-average temperatures in the north. Earlier on Tuesday, green groups called for the COP26 conference, which was put back from last year due to the COVID crisis and is scheduled to take place from Oct. 31 to Nov. 12 in Glasgow, to be delayed. Typically delegates from more than 190 countries attend the annual talks, yet with many countries grappling with COVID-19 and poorer nations struggling to access vaccines, they should be postponed, the Climate Action Network (CAN) said. read more