The World Meteorological Organisation (WMO) says 2014 is on track to be one of the hottest, if not the hottest, on record, according to its preliminary estimates released during the climate talks here.

This was largely due to record high global sea surface temperatures, which will very likely remain above normal until the year-end. High sea temperatures, together with other factors, contributed to exceptionally heavy rainfall and floods in many countries and extreme drought in others. The WMO’s provisional statement on the Status of the Global Climate in 2014 indicated that the global average air temperature over land and sea surface for January to October was about 0.09°C above the average for the past 10 years (2004-2013).

The statement says that if November and December maintain the same tendency, then 2014 will likely be the hottest on record, ahead of 2010, 2005 and 1998. This confirms the underlying long-term warming trend. It is important to note that differences in the rankings of the warmest years are a matter of only a few hundredths of a degree, and that different data sets show slightly different rankings, the WMO pointed out.

During the year, sea surface temperatures increased nearly to El Niño thresholds but this was not coupled with an atmospheric response. However, many weather and climate patterns normally associated with El Niño/Southern Oscillation (ENSO) were observed in many parts of the world.

“The provisional information for 2014 means that 14 of the 15 warmest years on record have all occurred in the 21st century,” said WMO Secretary-General Michel Jarraud in the statement issued on Wednesday.

The provisional statement was published to inform the annual climate change negotiations taking place in Lima.

The provisional statement also points out that average air temperatures over land for January to October 2014 were about 0.86°C above the 1961-1990 average, the fourth or fifth warmest for the same period on record. Western North America, Europe, eastern Eurasia, much of Africa, large areas of South America and southern and western Australia were especially warm. Final updates and figures for 2014 will be published in March 2015.

The latest analysis of observations by the WMO Global Atmosphere Watch Programme shows that atmospheric levels of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) reached new highs in 2013. Data for 2014 have not yet been processed.

Heat waves

Heat waves occurred in South Africa, Australia and Argentina in January. Australia saw another prolonged warm spell in May. Record heat affected northern Argentina, Paraguay, Bolivia and southern Brazil in October. Notable cold waves were reported in the U.S. during the winter, Australia in August and in Russia in October.

Temperatures were particularly high in the Northern Hemisphere from June to October for reasons which are subject to intense scientific investigation, according to the statement.