The El Niño Southern Oscillation (ENSO) is one of the important cycles affecting global weather, particularly around the Pacific region, but also having indirect impacts on a global level. Changes to winds and precipitation causing floods and droughts depending upon the region. El Niño also results in increasing global average temperatures, on top of the long term trend associated with climate change.
| Cost estimates in US$ for 1982-1983 El Niño | |
|---|---|
| Extreme Event / Country | Cost in $millions |
| Flooding | |
| Bolivia | $300 |
| Ecuador, Northern Peru | $650 |
| Cuba | $170 |
| U.S. Gulf States | $1,270 |
| Hurricanes | |
| Tahiti | $50 |
| Hawaii | $230 |
| Droughts/Fires | |
| Southern Africa | $1,000 |
| Southern India, Sri Lanka | $150 |
| Philippines | $450 |
| Indonesia | $500 |
| Australia | $2,500 |
| Southern Peru, Western Bolivia | $240 |
| Mexica, Central America | $600 |
| Total Costs | $8,110 million |
| Source: NASA via University of California San Diego | |
he 1982-1983 event has been estimated to have caused about $8.1 billion in damages and was largely unexpected without the warning and forecasting systems we have in place today.
The last Super El Niño event in 1997-1998 resulted in about 23,000 people killed as a result of ENSO linked extreme weather events and caused about $45-50 billion in losses to global agricultural output according to a Canberra Times report.
Predicting El Niño events and issuing alerts allows communities to prepare for the worst. It is essential for farmers to know the forecast for rain or drought so that crop plantings can be varied and livestock rates altered to minimise losses.
Predicting the development of El Niño
At the start of 2014 ocean models suggested El Niño may be developing in 2014. Predicting El Niño prior to the southern Autumn has been notoriously difficult to do with any accuracy. Usually El Niño predictions can only be made up to 6 months ahead due to the autumn predictability barrier. Climate professor Roger Stone said although it was very early to make a prediction, he told ABC, "There's some hint from the US ocean models and the European Union ocean models which are are some of the best, that there's some potential for an El Nino developing around mid year and that could have an influence on our winter crop and into summer."James Hansen, Makiko Sato and Reto Ruedy in their Global Temperature Update Through 2013 (PDF) detailed that "It appears that there is substantial likelihood of an El Niño beginning in 2014, and as a result a probable record global temperature in 2014 or 2015."
Cutting edge research out of the Potsdam Institute for Climate Impact Research in July 2013 has provided a method for extending forecasting from 6 months to one year or even more avoiding the autumn predictability barrier which traditional climate models have so much difficulty with. The researchers used network analysis to extend El Niño predictability out to about a year in advance. Ludeschera et al (2013) show that "our method correctly predicted the absence of El Niño events in 2012 and 2013 and now announce that our approach indicated (in September 2013 already) the return of El Niño in late 2014 with a 3-in-4 likelihood."
"Enhancing the preparedness of people in the affected regions by providing more early-warning time is key to avoiding some of the worst effects of El Niño," said Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research and co-author of the study lead by Josef Ludescher.
While neutral ENSO conditions persist, increasing number of models suggest possible onset of El Niño end of 2014 pic.twitter.com/PKf47KcOyF
— Frere Tak (@takvera) February 8, 2014Tropical Pacific Observing System
Predicting El Niño requires numerous measurements of ocean and atmospheric conditions. But one of the problems with this is it's dependence on a network of buoys and sensors in the mid pacific known as the Tropical Pacific Observing System set up by the USA and Japan. This observation system was set in place after the 1982-1983 extreme El Nino caused an estimated financial cost of damages of $8.1 billion.
This network has suffered under US Congress budgetary restrictions with a dramatic decline in operation of many buoys over the last couple of years to as little as 40 per cent of the network still operating. This impacts the ability of researchers to forecast conditions. It seems this warning system is at least getting some needed attention according to this Bloomberg report from March 2014.
The odds of El Niño had lifted by March according to BOM, even with the Autumn prediction barrier.
BOM saying El Nino likely by end of 2014 with reduced rain, #drought for Australia http://t.co/mqr6I0ZSWi pic.twitter.com/FNXPiVliY5
— Frere Tak (@takvera) March 11, 2014In April 2015 the World Meteorological Organisation warned that an El Niño was increasingly likely to occur: “El Niño and La Niña are major drivers of the natural variability of our climate. If an El Niño event develops – and it is still too early to be certain – it will influence temperatures and precipitation and contribute to droughts or heavy rainfall in different regions of the world,” said WMO Secretary-General Michel Jarraud.
“El Niño has an important warming effect on global average temperatures, as we saw during the strong El Niño in 1998” said Mr Jarraud. “Only two out of the past 15 years were categorized as El Niño years, and yet all were warmer than average. “The combination of natural warming from any El Niño event and human-induced warming from greenhouse gases has the potential to cause dramatic rise in global mean temperature,” he said in a media release.
The Ocean temperature Anomaly by April was registering an extraordinary +1.12 C Above Average by the end of April.
Ocean Temperature Anomaly Hits Extraordinary +1.12 C Above Average Reading on April 22 #ENSO http://t.co/qBM19wX3D8 via @FantasyScribe
— Frere Tak (@takvera) April 24, 2014NASA: 2014 similar to 1997 in El Niño development
NASA produced images of the ocean temperature anomaly comparing May 2014 to May 1997.
The maps above show the ten-day average of sea surface height centered on May 2, 1997 (left), and May 3, 2014. Shades of red and orange indicate where the water is warmer and above normal sea level. Shades of blue-green show where sea level and temperatures are lower than average. Normal sea-level conditions appear in white. The 1997 map was assembled from data collected by the TOPEX/Poseidon satellite, while the 2014 data comes from the Ocean Surface Topography Mission/Jason 2 satellite.
The height of the sea surface is a good indicator of the amount of heat stored in the water. As the ocean warms, the surface rises; as it cools, its falls. This is due to thermal expansion and contraction; the molecules in warmer water are farther apart than in cooler water. Above-normal sea surface heights in the equatorial Pacific indicate El Niño conditions, while below-normal heights indicate La Niña. (You can see an example of La Niña here and El Niño here.)
“What we are now seeing in the tropical Pacific Ocean looks similar to conditions in early 1997,” said Eric Lindstrom, oceanography program manager at NASA headquarters. “If this continues, we could be looking at a major El Niño this fall. But there are no guarantees.” Observations from a network of sensors within the Pacific Ocean support the satellite view, showing a deep pool of warm water that has been sliding eastward since January.
Climate scientist Kevin Trenbeth told Peter Sinclair of the Climate Crocks website in early May:
"Well I think the official announcements that have come out from the weather service and the climate prediction centre have been very conservative on this front. There are some things going on in the tropical pacific ocean right now that we haven't seen since the 1997-1998 El Niño event. I don't think the question is whether it will be an El Nino but think we are going to have an El Niño. The question is how large it is going to be and whether we will see something as big and therefore as disruptive as the 1997-1998 event. That's the really big question that is out there."
This is how Sea Surface temperature anomaly in the Pacific looked on May 22, 2014
Read about the Pacific equatorial Trade winds faltering on Robert Scribblers excellent blog - Winds Interrupted — El Nino is Tearing a Hole Through the Trades. He has also blogged on the Indian Monsoon At Dead Halt: Chances For Summer El Nino Jump to 70% as India Swelters
Fantastic analysis, but frightening: El Nino is Tearing a Hole Through the Trades Winds http://t.co/ZviD20gMT2 via @FantasyScribe #ENSO
— Frere Tak (@takvera) June 5, 2014Average impact of El Niño results in extensive drought
The Bureau of Meteorology have mapped the Winter-Spring rainfall decile ranges for 12 moderate-strong classical El Niños. A rainfall deficit and the likelihood of drought is shown for all of Eastern Australia.
ENSO Interaction with the Pacific Decadal Oscillation (PDO)
The 1997-1998 El Niño event likely triggered a phase change in the Pacific Decadal Oscillation (PDO) from positive to negative. The PDO is another ocean-atmosphere cycle with a much longer cycle period of 15-30 years which acts to bury atmospheric heat into the deeper layers of the ocean during a negative phase and release some of the built up ocean heat during a positive phase. Global warming is likely to spike record global temperatures when Pacific Decadal Oscillation moves to a positive phase.
Kevin Trenbeth in conversation with Peter Sinclair on El Niño and the change in phase of the Pacific Decadal Oscillation (PDO).
Trenbeth implicates extra warm waters in the western Pacific along with elevated sea levels with the destruction in the Philippines by super typhoon Haiyan.
Climate Change impact on El Niño and Indian Ocean Dipole
There has been quite a bit of recent research on how climate change will impact El Nino conditions. Schellnhuber from PIK warned in July 2013 that "It is still unclear to which extent global warming caused by humankind's emissions of greenhouse gases will influence the ENSO pattern. Yet the latter is often counted among the so-called tipping elements in the Earth system, meaning that at some level of climate change it might experience a relatively abrupt transformation."
An 'abrupt transformation'...that should sound alarm bells in the corridors of power. But in Australia we have a Prime Minister in denial of the climate science and winding back climate science programs, clean energy and climate mitigation policy.
Power et al (2013 found that El Niño is likely to become more intense with climate change, and produce drier conditions for Australia and the Western Pacific, with increases in rainfall in the central and eastern equatorial Pacific in the mid to late twenty first century. McGregor et al (2013) analysed past intensity of El Niño and La Nina events finding that the most recent 30 year period was more active and intense than any time in the last 600 years. Research by Cai et al (2014) showed that global warming is doubling the risk of extreme El Niños.
It seems that the El Nino Southern Oscillation (ENSO) is another tipping point we have to be worried about.
And on top of the forecasts for greater El Nino impacts, new research highlights we may see a three fold increase in the frequency of floods, droughts and bushfires from more extreme Indian Ocean Dipole events. This will affect Australia and other Indian Ocean Rim countries.
Our summer heatwaves and droughts in Australia are set to get a whole lot worse.
Sources:
- Peter Sinclair - Climate Denial Crock of the Week, 8 May 2014 - New Video: El Nino – What Are the Odds?
- WMO media release No 990 - WMO Update Indicates Possible onset of El Nino Around Middle of Year
- Peter Hannam, Canberra Times, 22 January 2014 - Tipping El Ninos harder as Pacific sensor array output 'collapses'
- James Hansen, Makiko Sato and Reto Ruedy, 21 January 2014 - Global Temperature Update Through 2013 (PDF)
- Sam Burgess, ABC Rural, 9 January 2014 - El Nino possibly developing later this year
- Scott Power, François Delage, Christine Chung, Greg Kociuba & Kevin Keay, Robust twenty-first-century projections of El Niño and related precipitation variability (abstract), Nature (2013) doi:10.1038/nature12580
- McGregor, S., Timmermann, A., England, M. H., Elison Timm, O., and Wittenberg, A. T.: Inferred changes in El Niño–Southern Oscillation variance over the past six centuries, (abstract), Clim. Past, 9, 2269-2284, doi:10.5194/cp-9-2269-2013, 2013
- Wenju Cai, Simon Borlace, Matthieu Lengaigne, Peter van Rensch, Mat Collins, Gabriel Vecchi, Axel Timmermann, Agus Santoso, Michael J.McPhaden, Lixin Wu, Matthew H. England, Guojian Wang, Eric Guilyardi & Fei-Fei Jin, (2014) Increasing frequency of extreme El Niño events due to greenhouse warming. (abstract) Nature Climate Change 4, 111–116 (2014) doi:10.1038/nclimate2100
- Josef Ludeschera, Avi Gozolchianib, Mikhail I. Bogacheva,c, Armin Bundea, Shlomo Havlinb, and Hans Joachim Schellnhuber (2013) Very early warning of next El Niño (abstract) Proceedings of the National Academy of Sciences (early online edition) [DOI:10.1073/pnas.1309353110]
- Potsdam Institute for Climate Impact Research media release, 2 July 2013 -Breakthrough in El Niño-Forecasting
- NASA Earth Observatory, 14 May 2014 - Is El Niño Developing?
- Wenju Cai, Agus Santoso, Guojian Wang, Evan Weller, Lixin Wu, Karumuri Ashok, Yukio Masumoto & Toshio Yamagata (2014) Increased frequency of extreme Indian Ocean Dipole events due to greenhouse warming (abstract) Nature 510, 254–258 (12 June 2014) doi:10.1038/nature13327
- Karen Palenzuela, ABC Environment, 12 June 2014 - Climate change set to triple drought, bushfires and floods in Australia
- Lead image is from NOAA showing the general ElNino impact on rainfall for the globe.
- Wenju Cai, Agus Santoso, Guojian Wang, Evan Weller, Lixin Wu, Karumuri Ashok, Yukio Masumoto & Toshio Yamagata (2014) Increased frequency of extreme Indian Ocean Dipole events due to greenhouse warming (abstract) Nature 510, 254–258 (12 June 2014) doi:10.1038/nature13327
- Karen Palenzuela, ABC Environment, 12 June 2014 - Climate change set to triple drought, bushfires and floods in Australia
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