La Nina, Spanish for ‘Little girl’, is the ‘cool’ phase of the slighter better known El Nino or ‘The boy’ which represents the ‘Southern Oscillation’ in its ‘warm’ phase. The combined effects of the two are generally referred to as Enso and this is, broadly speaking, a periodic climate pattern previously known to occur in the tropical eastern Pacific Ocean zone every five years or so with El Nino generally being of longer duration than his little sister.

The arrival of an El Nino event is announced by the ocean surface warming in this particular area by at least 0.5C above average and La Nina by a reduction of a similar degree. This, along with alterations in surface pressure over Australia, Indonesia and the Indian Ocean and corresponding changes in the ‘trade winds’ serve as an early warning system that one or the other face of Enso is about to make an impact. Each separate event can last from nine months to two years and, until as recently as 20 years ago, was relatively easy to predict but all this changed in 1986 when a completely new phenomenon arose.

The traditional Enso, centred on ocean surface temperature anomalies in the eastern Pacific Ocean could very well have been pushed aside by what has been christened El Nino ‘Modoki’, this word meaning ‘different’ in Japanese, which arises in the central rather than the eastern Pacific and which has some new ingredients including the formation of an increased number of Atlantic Ocean hurricanes.

This new version, the Central Pacific El Nino/La Nina, has occurred six times since first being observed in 1986 with the strongest one running from 2009-10 in its El Nino phase and from around June 2010 until either the summer of 2011 or the early months of 2012 depending on which climatologist is correct, in the shape of La Nina.

It is this La Nina being experienced right now which is causing cooler ocean surface temperatures in the Pacific and strengthening trade winds thus causing heavier precipitation in Australia, Sri Lanka and Brazil.

It also results in higher than normal rainfall in the southern part of the African continent over the winter months into early spring and drought conditions in equatorial East Africa at the same time. Heavy rains also occur in places such as Malaysia, Indonesia and the Philippines during this period plus in Northern Brazil, the American Midwest, the Northern Rockies and Northern California amongst others.

This long lasting La Nina event also means that surface air temperatures are liable to continue to be below normal for the next few months and this is liable to adversely impact agricultural production in places including Eurasia, North America, Australia, Brazil, Southern Africa and also here in Pakistan where agricultural outputs slumped in 2010 as a direct result of massive flooding which rendered an estimated 10 million people homeless and from which large areas of submerged land have yet to re-emerge.

Hundreds of lives were lost in Australia, Brazil and Sri Lanka and tens of thousands more made homeless as a result of La Nina instigated floods of massive proportion over recent weeks. However, according to some climatologists, the distinct possibility of these calamitous events was known as early as June 2010. If preventative action had been initiated at that time, it could have saved both precious lives and property but, as always in such cases; human beings prefer to ignore warnings of dire catastrophe than to face actually reality.

Increasingly ‘energetic’ climatic aberrations are, according to concerned experts in the relevant fields, liable to become the ‘norm’ with destructive incidents such as the flooding in Pakistan in 2010 and debilitating heat wave and wild fires in Russia at the same time, becoming far more common than in even the recent past. Current flooding events, floods recently occurred in many other regions aside from those already mentioned, are an indication of unpredictable weather patterns to come as is the unprecedented cold wave that struck southern China in late December to early January that lead to the evacuation of thousands of people from mountainous localities before they were frozen to death, or died of hunger, when communication links were severed.

Some confused climatologists are laying the blame for erratic weather swings on manmade climate change and a minority clinging to other, less provable ideas. It is apparent that meteorological departments around the world need to embark on even more information sharing than they already do and that they pass on relevant information concerning potentially harmful climate events as soon as they possibly can so that governments, organisations, farmers and private individuals can prepare for what is, after all is said and done, inevitable.