Al Jazeera — Since May 2015, 13 out of 14 months have either tied or set new global heat index records. Only May 2016 came up short – it was merely the second warmest May on record.
It is hardly surprising that the record-breaking sequence continued in July, as confirmed by NASA’s Goddard Institute for Space Studies.
July was 0.86C above the 20th Century average, and 0.1C warmer than the previous warmest July on record, in 2011, by 0.1C.
What makes this record particularly noteworthy is that this was the warmest month – of any month – since records began in 1880, beating the previous 1,620 months.
July is usually the warmest month in most years, as the northern hemisphere contains the bulk of Earth’s landmass, and northern summer temperatures peak during July.
The record also lends weight to the assertion by NASA, the National Oceanic and Atmospheric Administration, the European Centre for Medium-Range Weather Forecasting (ECMWF), the Japan Meteorological Agency and the UK Met Office that 2016 will be the warmest year since records began, beating 2015 and 2014 into second and third places, respectively.
“These record-breaking extremes are the result of a cocktail of weather phenomena and human activity … We are already seeing the human cost of hotter conditions with the impact of reported wildfires and other events,” said Jean-Noel Thepaut of ECMWF’s Copernicus Climate Change Service.
Related to rising global air temperatures is the decline in the extent of Arctic sea ice. The US National Snow and Ice Data Center reported that, as of August 14, ice coverage was at its third lowest since 1979.
Until a few days ago, it was thought that ice extent would be close to, or just above, the record low of 2012.
Recently, however, there have been dramatic developments in the Arctic Circle. Weather Underground’s Dr Jeff Masters reports that an intense cyclone, centred in the Arctic Ocean, could have a major impact on Arctic sea ice distribution in the coming months.
Low pressure centres tend to result in cool and cloudy weather, which thwarts summer ice fragmentation. But this cyclone is extremely intense, with a central pressure of 968mb. It is highly unusual for such an intense cyclone to form in the Arctic during the summer.
A similarly intense storm developed during the record-breaking summer of 2012. Strong winds and surface waves pushed warm surface waters up against the ice floes, hastening their disappearance.
For climate scientists and meteorologists, this is relatively “unknown territory”. There is no guarantee that this storm, or another one which may form in coming days, will have a negative impact of the ice, but computer models predict a general decrease in surface pressure in the Arctic region.
At a time when the Arctic is opening up to more shipping – both cargo and passenger traffic – changes to the ocean and atmosphere of the Arctic will need to be closely monitored.