22 September 2015: The World Meteorological Organization (WMO) has reported on the issuance by the National Snow and Ice Data Center (NSIDC) of a preliminary announcement stating that Arctic sea ice reached its minimum extent for 2015 on 11 September at 4.41 million square kilometers (1.70 million square miles), the fourth lowest minimum since satellite records began at the end of the 1970s. According to WMO, this reinforces a long-term downward trend in Arctic ice extent, while in the Antarctic, sea ice extent is average, in contrast with recent years when Antarctic winter extents reached record high levels.

WMO indicated that Arctic sea ice extent is beginning its seasonal increase through autumn and winter due to falling temperatures and earlier sunsets. It adds that since this is a preliminary announcement, a shift in wind patterns or a late season melt could still push the ice extent lower, as was the case in 2005 and 2010. In early October, NSIDC will release a full analysis of the Arctic melt season and discuss the Antarctic winter sea ice growth.

In related news, WMO reported that, according to preliminary findings of the assessment of the state of the climate in the current five-year period, global mean temperatures near the Earth’s surface continued to set new records between 2011 and 2015, consistent with rising atmospheric greenhouse gas (GHG) levels.

WMO indicated that 2014 was nominally the warmest on record, with global mean temperatures 0.61°C above the 1961-1990 period average. It further notes that 2015 is continuing on a similar track, with temperatures for January to July at 0.70°C above the long-term average, and El Niño is expected to influence the climate for the rest of 2015.

A WMO brochure outlining the issue provides information about temperatures, the El Niño/Southern Oscillation and other large- scale climate drivers, extreme events, the Polar regions and sea levels, and will be available to delegates at the UN Sustainable Development Summit, which is convening from 25-27 September 2015 in New York, US. WMO is expected to publish a more detailed report, as well as the WMO’s provisional statement on the status of the climate in 2015, ahead of the UN Climate Change Conference scheduled to take place in Paris, France, in November-December 2015.

On 17 September, the US National Oceanic and Atmosphere Administration (NOAA) reported that August was the warmest August on record. Global average temperature across global land and ocean surfaces was 0.74°C above the average for the 1961-1990 reference period, and 0.88°C above the 20th Century average, making it the sixth month in 2015 to break its monthly temperature record. The average January-August temperature across global land and ocean surfaces was the highest for the period in the 1880-2015 record. [WMO Press Release, Arctic Sea Ice] [NSIDC Press Release] [WMO Press Release, Global Temperatures] [WMO Brochure] [NOAA Summary Information for August] [IISD RS Story on First Half of 2015 Warmest on Record]