Extreme weather events of 2013 a result of human influences: WMO

Year 2013, like 2007, was the sixth warmest on record and continued the long-term global warming trend, said the World Meteorological Organization (WMO). The international body, which issued its annual statement on the Status of the Climate on World Meteorological Day (March 23), highlighted the key climate events of 2013.

Thirteen of the 14 warmest years on record have all occurred in the 21st century, and each of the last three decades has been warmer than the previous one, culminating in 2001-2010, which was the warmest decade on record. The average global land and ocean surface temperature in 2013 was 14.5°C (58.1°F) – 0.50°C (0.90°F) above the 1961–1990 average and 0.03°C (0.05°F) higher than the 2001–2010 decadal average. Temperatures in many parts of the southern hemisphere were especially warm, with Australia having its hottest year on record and Argentina its second hottest.

Australia’s recent heat waves gain focus

The Status of the Climate Report contains a peer-reviewed case study of Australia’s record warmth in 2013. The study by scientists at the ARC Centre of Excellence for Climate System Science University of Melbourne, Australia, used nine state-of-the-art global climate models to investigate whether changes in the probability of extreme Australian summer temperatures were due to human influences. The report provides a snapshot of regional and national temperatures and extreme events as well as details of ice cover, ocean warming, sea level rise and greenhouse gas concentrations—all inter-related and consistent indicators of our changing climate.

Naturally occurring phenomena such as volcanic eruptions or El Niño and La Niña events have always contributed to framing our climate, influenced temperatures or caused disasters like droughts and floods. But many of the extreme events of 2013 were consistent with what we would expect as a result of human-induced climate change, said WMO secretary-general, Michel Jarraud.

Heavier precipitation, more intense heat, and more damage from storm surges and coastal flooding as a result of sea level rise—as typhoon Haiyan so tragically demonstrated in the Philippines—were some of the examples, said Jarraud.

“There is no standstill in global warming,” said Jarraud. The warming of our oceans has accelerated, and at lower depths. More than 90 per cent of the excess energy trapped by greenhouse gases is stored in the oceans. Levels of these greenhouse gases are at record levels, meaning that our atmosphere and oceans will continue to warm for centuries to come. The laws of physics are non-negotiable.”

Comparing climate model simulations with and without human factors shows that the record hot Australian summer of 2012/13 was about five times as likely a result of human-induced influence on climate and that the record hot calendar year of 2013 would have been virtually impossible without human contributions of heat-trapping gases, illustrating that some extreme events are becoming much more likely due to climate change, the study concluded.

WMO’s statement, which is an internationally recognised authoritative source of information, has highlighted following key climate events of 2013:

  • Typhoon Haiyan (Yolanda), one of the strongest storms to ever make landfall, devastated parts of the central Philippines and claimed almost 10,000 lives
  • Surface air temperatures over land in the Southern Hemisphere were very warm, with widespread heat waves; Australia saw record warmth in the year, and Argentina its second warmest year and New Zealand its third warmest
  • Frigid polar air plunged into parts of Europe and the southeast United States
  • Angola, Botswana and Namibia were gripped by severe drought
  • Heavy monsoon rains led to severe floods on the India-Nepal border
  • Heavy rains and floods impacted northeast China and the eastern Russian Federation
  • Heavy rains and floods affected Sudan and Somalia
  • Major drought affected southern China
  • Northeastern Brazil experienced its worst drought in the past 50 years.
  • The widest tornado ever observed struck El Reno, Oklahoma in the United States
  • Extreme precipitation led to severe floods in Europe’s Alpine region and in Austria, Czech Republic, Germany, Poland, and Switzerland
  • Israel, Jordan, and Syria were struck by unprecedented snowfall
  • Greenhouse gas concentrations in the atmosphere reached record highs
  • The global oceans reached new record high sea levels
  • The Antarctic sea ice extent reached a record daily maximum.

The global temperature assessment is based on three independent datasets that are maintained by the Met Office Hadley Centre and the Climatic Research Unit of the University of East Anglia (HadCRU), both in the United Kingdom; the National Climatic Data Center of the National Oceanic and Atmospheric Administration (NCDC NOAA), based in the United States; and the Goddard Institute for Space Studies (GISS) operated by the National Aeronautics and Space Administration (NASA), also in the United States.

http://www.downtoearth.org.in/news/extreme-weather-events-of-2013-a-result-of-human-influences-wmo-43843

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