A prolonged La Niña – what are the implications?

Courtesy: Worldcrops

Should we be getting agitated about the possible prolongation of La Niña weather? Yes and no. Yes, because the abnormal weather patterns that follow La Niñas are highly disruptive to a wide range of crop production. No, because the La Niña impacts this time round may be weaker, although strong enough to change the balance between surplus and deficit for some crops. Headlines along the lines of ‘La Niña is back’ are, however, misleading – it never entirely went away.

La Niñas often take their time to finally disappear. The La Niña that started forming in mid-2010, peaked around the turn of the year, then ebbed away a little, is simply dragging on. Although the doom-mongers of climate change will be tempted to see this as further evidence of a structural and alarming development, this pattern is not unusual.

The La Niña of May 1998-March 2001, for example, waxed and waned in its intensity, but it’s generally agreed it was a single, extended event. If we care to go back even further – before man-made climate change scares had surfaced – to La Niña of April 1954-January 1957, that 34-month event saw much less variation in its intensity. So if we are trying to peer forward, we might best be advised to settle down and await the final end of this La Niña in the first half of 2013.

Even if this La Niña turns out to be somewhat weaker in the (possibly) two years of its remaining life, it could have some pretty dramatic consequences for crops. In very simple terms, the severe intensity of the La Niña so far has left certain large regions of the world in a poor state to combat very much more in the way of weather extremities.

The first whole year of this La Niña has been accompanied by record-breaking severe drought across much of the South Western and Southern states of the US, with dire consequences for cotton and cattle. Argentina and southern Brazil – key producers of soybeans and grains – may well experience a drier-than-ideal period in the run-up to the end of 2011. Arabica coffee output could also be threatened in Brazil, where the state of Minas Gerais – centre of the country’s coffee-producing region – had almost no rain in July and 70% less than the long-term average in August. If – as seems to be happening – rainfall is highly erratic in September, then the crucial flowering of the coffee trees is in danger of aborting, thus reducing the overall final harvest.

But it’s an ill wind that blows no one any good. La Niñas tend to correlate with plentiful rainfall in West Africa, helping to produce strong cocoa harvests. Few thought that last season’s record-busting West African cocoa output could be repeated – but perhaps they will be wrong. And the widely anticipated global cocoa deficit in 2011-2012, perhaps >100,000 tonnes, may disappear, after all. Certainly, those speculative investors who have helped international cocoa prices remain around $3,000/tonne for so long – far in excess of what the supply-demand fundamentals have justified, following a big surplus this past season – seem to have taken fright. Last week the price dropped 4% in New York. They are probably taking note of La Niña – as well as sluggishly growing demand.

India: Disasters to surge last quarter. La Niña-Dipole Double Whammy

The 2010-2011 La Niña was one of the strongest in recorded history. Its first phase ended in April this year and after the boreal summer, the La Niña as appeared again. However, the second phase of a La Niña is usually weaker than its first phase. 

But with the Indian Ocean Dipole (IOD), another oceanic phenomenon emerging concurrently it should give the effects of the La Niña an extra punch. This means the NE Monsoon can be expected to be vigorous over the Indian sub-continent. The threat level for disasters like flooding and cyclones during the last quarter of the year remains high. 

‘Dipole' in Indian Ocean as La Niña looks to grow

Courtesy: Hindu Business Line

La Niña conditions re-emerging in the equatorial east Pacific will grow in intensity in due course, says the Tokyo-based Regional Institute for Global Change (RIGC).

First off the block with a ‘repeat' La Niña forecast made late last year since proven true, the RIGC said in an update that the event would peak during the winter and die out by March-April-May 2012. This is also expected to keep mercury lower than normal, providing for a colder winter as was the case during the past few years.

The Climate Prediction Centre of the US National Weather Services and the Australian Bureau of Meteorology (BoM) have since confirmed the La Nina status.

In another case of RIGC outlook having been made many months ago and now proving true, the BoM has said that a positive Indian Ocean Dipole (IOD) event is evolving.

A positive IOD represents warming anomalies to the west of equatorial Indian Ocean relative to the east. It is known to boost a concurrent Indian monsoon, now in the last phase, though.

The RIGC has indicated excess rainfall for most of the country through September-October-November, a likely result from a La Niña-positive IOD combine.

POTENT COMBINE

The combination is also seen as prolonging the monsoon rains over India, with a fresh low-pressure area having been tossed up over the Bay of Bengal.

Associated with the developing La Niña, cool to wet conditions would occur in the southern Africa, Australia, and Brazil, the RIGC said.

The La Nina would also help bring down the surface temperature over many parts of the globe except the northern Eurasia and southern US.

Wet to flooding conditions have been warned of in Indonesia, India, and eastern Africa. Northeast Asia (eastern China, Korea and western Japan) would have warm/wet during autumn and colder weather in winter.

Above average monsoons leave Indian Met Office red-faced! Prospects of second consequent bumper harvest leave Oxfam red-faced!

The UK Met Office has now become globally a butt of jokes, after predicting a "barbecue summer", three years in a row and proved wrong in all three occasions - their global warming bias proving their Waterloo. Such as been their loss of public confidence that they have given up seasonal forecasting altogether.

The India Meteorological Department (IMD) is faring no better. Using the same IPCC’s statistical modelling techniques, IMD in April predicted the current monsoon season's rainfall at 98 per cent of Long Period Average (LPA) and then revised it downwards to 95 per cent on June 19 and further to 92.5 per cent on  August 1 while further  suggesting a below normal' rainfall of 90 per cent for August-September. 

But as on September 15^th, the country received more than 103 per cent rainfall of the LPA. Rainfall was fairly well distributed with only four of the 36 meteorological sub-divisions recording moderately deficit.  The rainfall IMD map shows Rajasthan, West Madhya Pradesh, Saurashtra, Kutch and Diu, Konkan and Goa, coastal Karnataka and Uttarakhand receiving excess rainfall, while 24 sub-divisions getting normal rains. Last month was, indeed, the wettest August in 15 years with nearly 10 per cent surplus rains, while amounting to 123 per cent of LPA for the first two weeks of September.

South Asia experiences monsoon rains from June to September, which are vital for its agriculture. But above average rains can cause widespread floods as seen this year. 16 million people have now been affected by flooding caused by heavy and sustained monsoon rains falling across south Asia. The floods have caused massive displacement of populations across Pakistan, India, Bangladesh and Nepal and brought widespread destruction to homes, livelihoods and agricultural cropland. In India, an estimated  5.2 million people in the worst hit areas of Bihar, Uttar Pradesh and Assam in the northeast of the country have had their lives disrupted by the flooding, which was sparked by incessant rains that caused burgeoning rivers to overflow and embankments to breach. 158 people have died so far, mainly due to drowning.

Normally, withdrawal of monsoon from west Rajasthan starts around September 1 but it is yet to do so this year. The withdrawal is usually complete by around mid September. The late monsoon withdrawal may mean wet conditions are here to stay till the month end. The Australian Bureau of Meteorology (BoM) has said in the latest update that a rain-friendly Madden-Julian Oscillation (MJO) wave is in the process of transiting the Indian Ocean from west to east.

The Climate Prediction Centre (CPC) of the US National Weather Services meanwhile said in its latest outlook for the week beginning on Wednesday that an enhanced monsoon flow is expected to enhance rainfall in northern India, the Bay of Bengal and Southeast Asia. This is being attributed to the sustained above average sea surface temperatures over the western equatorial Indian Ocean that helps convection (process of cloud building). 

Red-faced IMD officials, attempting to explain their failure said:

"A strong cross equatorial flow around Arabian sea in the second week of July played an important role in causing rainfall. This is being attributed to the sustained above average sea surface temperatures over the western equatorial Indian Ocean that helps convection (process of cloud building).” 

But we saw the same phenomenon last year, just as we saw late withdrawal of the monsoon. Also, last year, rainfall was around 105 per cent of LPA. The late withdrawal of the monsoon and continuing rainfall means we are on the way to either equal or better this mark.  All these characteristics bear the stamp of the La Niña. This prompted The Hindu to comment:

“The IMD should, perhaps, shed its fetish for statistical (extrapolation of historical data) forecast models over dynamical ones based on real-time physics of atmospheric fluid flows. The disparity is best brought home in the way the IMD dismissed, as recently as in August, the possibility of a crucial La Niña event developing in the East Pacific — which dynamical models had been harping on for months together.”

Last year’s La Niña accounted for the good rains in India and the drought in East Africa. During El Niños, the reverse applies with India tending to experience drought and East Africa floods. Both cycles alternate once in 3-5 years. The in-between phase is described as El Nino-Southern Oscillation (ENSO) neutral conditions. The La Niña is the alter ego of El Niño a naturally occurring climate phenomenon located over the tropical Pacific Ocean and results from interactions between the ocean surface and the atmosphere. 

During La Niña, cooler-than-average Pacific Ocean temperatures influence global weather patterns, resulting in temporary global cooling.  The strong 2010-11 La Niña contributed to record winter snowfall, spring flooding and drought across the United States, as well as other extreme weather events throughout the world, such as heavy rain in Australia and an extremely dry equatorial eastern Africa.

La Niña typically occur every three-to-five years and lasts normally for nine months with back-to-back episodes occurring about 50 percent of the time. Last year’s La Niña surfaced around May and predictably disappeared by April this year. Most of the long range forecast from reputed climate research centres had negated the re-emergence of the La Niña after the boreal (northern hemisphere) summer and predicted ENSO neutral conditions. The IMD followed suit and ended up with mud on their faces.

This blog in contrast had taken the contrarian position, predicting a multi-year La Niña as far back as October 9 2010 through our post: Now, the Monster of a La Niña Confirmation???  We had then forecasted that the La Niña of 2010-2011 would take a break during the boreal summer and re-emerge by fall only to intensify by northern hemisphere winter.  Our reasons were based on the following:

a.    Analysis of historical data indicates that a multi-year La Niñas tended to occur whenever its first phase onset was rapid and its strength, strong. The 2010-2011 La Niña was one of the strongest in recorded history and also one of its rapidest.

b.    We tracked the NCEP/CFS forecast, based on dynamic models, which was one of the first to declare the onset of the 2010-2011 La Niña and predicted a high probability for a multi-year La Niña.

As we expected, the La Niña is back and now it is official. The US, National Oceanic and Atmospheric Administration (NOAA) have announced that La Niña has re-emerged in the Pacific Ocean and is expected to gradually strengthen and continue into the Northern Hemisphere’s winter.

But this is bad news for NGOs like Oxfam whose CEO, Barbara Stocking was quoted in their latest report “Growing a Better Future in a Resource Constrained World”  made the shocking comment that  "The food system is pretty well bust”. Stocking’s NGO claims that it is all because of climate change and making it imperative for agriculture to contribute its mite to reduce its carbon footprint.  Read more: OXFAM morphs into a Paul Ehrlich clone: Claims world faces mass starvation! 

The good monsoon this year has boosted the prospects of Kharif harvest. According to the government data, following good rains in most parts of the country so far, the area under cultivation under all major crops has shown a significant rise this year compared with the last year. Higher area and well distributed rainfall will help India achieve its target of increasing its food grains output to an all time record 245 million metric tons. All crop production is expected to be up except for pulses, coarse cereals and groundnut output. 

Since publication of their report: “Growing a Better Future in a Resource Constrained World” and making the flustering claim that "The food system is pretty well bust”.

2011-12 would be the second consequent year India would be recording an all time bumper harvest! If climate change causes farms to go bust, and if this is the outcome, Indians should be rejoicing to demand “Let’s have more of it!”