2015 likely to be the warmest year on record: WMO

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Who: Provisional Statement on the Status of Global Climate in 2011-2015
What: Released by WMO
When: 25 November 2015

The World Meteorological Organization (WMO) on 25 November 2015 released Provisional Statement on the Status of Global Climate in 2011-2015. According to it, the global average surface temperature in 2015 is likely to be the warmest on record.

The average surface temperature in 2015 can reach the symbolic and significant milestone of 1° Celsius above the pre-industrial era.

The reason behind such surface temperature is combination of a strong El Nino and human-induced global warming.

Highlights of the analysis

  • The years 2011-2015 have been the warmest five-year period on record at about 0.57°C (1.01°F) above the average for the standard 1961-90 reference period.
  • Levels of greenhouse gases in the atmosphere reached new highs in the year 2015.
  • In the Northern hemisphere spring 2015, the three-month global average concentration of CO2 crossed the 400 parts per million barrier for the first time.
  • A powerful El Nino event is being witnessed in 2015, which is still gaining in strength. This is influencing weather patterns in many parts of the world and fuelled an exceptionally warm October.
  • The overall warming impact of this El Nino is expected to continue into 2016.
  • A preliminary estimate based on data from January to October 2015 shows that the global average surface temperature for 2015 so far was around 0.73 °C above the 1961-1990 average of 14.0°C and approximately 1°C above the pre-industrial 1880-1899 period.
  • South America is having its hottest year on record, as is Asia (similar to 2007) and Africa and Europe their second hottest.

Highlights of 2015

El Nino: The El Nino began in the North Pacific region in the summer of 2014 and spread to the South Pacific and Indian Ocean in 2015. Consistent with typical El Nino impacts, large areas of Central America and the Caribbean recorded below average rainfall.

Ocean heat and sea level rise: The oceans have been absorbing more than 90 percent of the energy that has accumulated in the climate system from human emissions of greenhouse gases. In the first nine months of 2015, global ocean heat content reached record high levels.

Regional temperatures: Significant warmer than average temperatures were recorded over the majority of observed land areas, especially western North America, large areas of South America, Africa and southern and eastern Eurasia.

Heatwaves:  A major heatwave affected India in May and June 2015, with average maximum temperatures exceeded 42°C widely and 45°C in some areas. Heatwaves affected Europe, northern Africa and the Middle East through the late spring and summer.

Rainfall and drought: Areas of high rainfall included: southern areas of the USA, Mexico, Bolivia, southern Brazil, southeast Europe, areas of Pakistan and Afghanistan. 2015 saw exceptional seasonal rainfall totals in several parts of Burkina Faso and Mali.

There were many instances in 2015 of 24-hour total rainfall patterns exceeding the normal monthly mean of rain. While, dry areas included Central America and the Caribbean, northeast South America, parts of central Europe and Russia, Southeast Asia, Indonesia and southern Africa.

Tropical Cyclones: Globally, a total of 84 tropical storms formed between January 2015 and 10 November 2015. Hurricane Patricia which made landfall in Mexico on 24 October was the strongest hurricane on record. In the Northwest Pacific basin, 25 named storms were recorded. Six typhoons made landfall over China. Four named storms formed in the Northern Indian Ocean.

Arctic and Antarctic: In 2015, the daily maximum sea ice extent, which occurred on 25 February 2015, was the lowest on record at 14.54 million km. The minimum sea ice extent was on 11 September 2015 when the extent was 4.41 million km2, the fourth lowest in the satellite record.

Climate Change Attribution: Out of 79 studies published by Bulletin of the American Meteorological Society between 2011 and 2014, more than half found that anthropogenic climate change contributed to extreme events. The most consistent influence has been on extreme heat.

About Analysis Methods of WMO

  • The WMO reports on the Status of the Global Climate are based on contributions from WMO`s 191 Members.
  • The global temperature analysis is derived from datasets maintained by the Hadley Centre of the UK’s Met Office and the Climatic Research Unit, University of East Anglia, United Kingdom; the US NOAA National Centres for Environmental Information and the Goddard Institute of Space Studies (GISS).
  • Global average temperatures are also estimated using reanalysis systems, which use a weather forecasting system to combine many sources of data to provide a more complete picture of global temperatures.
  • WMO uses data from the reanalysis produced by the European Centre for Medium-Range Weather Forecasts and the Japan Meteorological Agency.