Carbonomics no.4: The Evidence of Anthropogenic Global Burning

El nino is a massive climatic phenomena which affects most of the tropics but it also has varying impacts around the world. It might have been thought its huge scale would have made it a matter of long standing scientific enquiry but, paradoxically, its sheer scale prevented scientists from realizing that a multitude of events were part of the same climatic phenomena. In the late 19thc, the british scientist, gilbert walker, recorded some of these climatic events but it took scientists decades of work on a variety of seemingly disparate climate events before they discovered the links between them .. "in the late 1960s a norwegian meteorologist, jacob bjerknes, put the whole picture together. As professor at the university of california, he was the first to see a connection between unusually warm sea-surface temperatures and the weak easterlies and heavy rainfall that accompany low-index conditions. Ultimately, bjerknes' discovery led to the recognition that the warm waters of el nino and the pressure seesaw of walker's southern oscillation are part and parcel of the same phenomenon - sometimes referred to by the acronym ENSO."

The first time the phenomena was appreciated in its entirety was the massive el nino of 1982-83 which affected weather patterns around the world, "The good news from the scientific point of view, even though it wasn't recognized as an el nino until it was half over, was that it created effects on the climate that couldn't be missed. North america experienced wildly unusual weather throughout 1983, australia experienced massive drought and devastating bushfires; it was one of the worst periods for drought in the sub-sahelian countries and the monsoons failed in the indian ocean. Total damages were estimated at somewhere between $8 billion and $13 billion and 2,000 lives were lost. It caught the weatherman's attention, so to speak." Climatologists continued to learn from subsequent el nino events, "The british meteorological office .. by 1989, had established a definite correlation between the temperature of the oceans and the rainfall totals falling in the sahel of west africa." Over the last two decades or so, climatologists have increasingly realized the importance of el nino to the global climate.

It took time for the scientific understanding of el nino to start permeating into the political realm. It would probably never have become a political issue if it wasn’t for global burning. Political interest in el nino has growing in response to increasing political concern about global burning. Global burning emerged as a political issue in the late 1980s whilst el nino emerged as a political phenomena a decade later primarily as a result of the 1997-98 el nino which was so massive it devastated many countries. This was one of the biggest el ninos ever recorded and it added considerably to the suspicions that global burning was affecting the Earth even if the links between global burning and el nino have yet to be established.

The scientific phrase for the unusual climate aberration affecting vast stretches of the pacific is el nino - southern oscillation (enso). The southern oscillation is an index of the difference in atmospheric pressure between two extremes points in the pacific, "In the first half of the 20th century meteorologists created a number of similar oscillating indexes. The southern oscillation, the difference between the pressure in darwin and in tahiti, measures the atmospheric component of the el nino effect, which is why (it is called) enso - el nino/southern oscillation." Its counterpart is the northern oscillation which covers the atlantic - for which see below.

In normal years, strong trade winds off the west coast of south america blow westward pushing the pacific ocean current towards asia. "Ordinarily, the south equatorial current, driven by the trade winds, carries surface water westward, away from south america and towards indonesia. Beneath this fairly shallow layer of surface water there is a boundary, the thermocline, below which the temperature drops sharply. The westward movement of surface water is compensated by an easterly flow along the thermocline, known as the equatorial undercurrent, or cromwell current. This system moves warm surface water westward, so the surface layer, above the thermocline, is about 200m deep around indonesia but very shallow off the american coast, where the thermocline almost reaches the surface."

The westerly trade winds pile pacific waters against the coastlines of australia, indonesia, and the philippines. The piled up water is about half a metre higher than that on the eastern side of the ocean. The warm water releases huge quantities of water vapour which creates clouds producing widespread rain, "Tropical rainfall is confined to the western Pacific during september and october, when the ocean waters are below 28C east of the date line. The ocean temperatures and distribution of tropical rainfall affect the atmospheric heating across the tropics and subtropics, with the largest heating coinciding with warmest ocean waters and heaviest rainfall." The puddle of warm water helps to produce the monsoons which strike south east asia, "Convection from this great body of hot water produces the clouds that bring the monsoon rains."

Periodically, the warm water piled up on the west pacific becomes warmer than usual - especially off papua new guinea, "El nino occurs every 3-8 years when the sea north of papua new guinea warms, reaching temperatures of 30C." It is not understood why this happens. Whatever the reason, the warmer the water gets the more likely it is to generate an el nino. The heat absorbed by the pile of water is colossal, "It contains more energy than has been procured from all the fossil fuels burned in the United States since the beginning of the century - that's all the gasoline in all the cars, the coal in all the power plants, the natural gas in all the furnaces. It would take more than a million large power plants, at 1,000 megawatts each, running full tilt for a year, to heat the ocean that much. Or if you want to think in more violent terms, that's all the energy produced by about half a million 20 megaton hydrogen bombs, gone into heating water." It has been alleged that, "(In the pacific) north of australia off Papua New Guinea, lies the warmest pool of sea water on the planet."

The build up of warm water in the west pacific eventually reaches the point where it spills eastward for thousands of miles across the pacific. The pool of warm water doesn’t move en masse but squirts out a stream of water which drains across the pacific toward south america, "Last year .. the great mass of warm water .. moved along the equator west to east. As it piled up on american shores a great tongue stretched out 6,000 miles behind into the pacific."; "In a narrow sense, it (el nino) is a giant puddle of heated water that sloshes across the pacific ocean. From nasa satellites, we can see the big picture; a massive pool of warm seawater, half again as large as the United States, builds in the western pacific over a period of months. This gargantuan wedge of warm sea contains 20 or 30 times as much water as all the great lakes put together. In one sense, it's like an iceberg; most of it is submerged, but part of it sticks out above the sea's surface, as the wedge floats in the surrounding ocean. Partly because warm water is less dense than cool water, and also partly because el nino waters are less salty than normal seawater. (It's always raining over an el nino, and the rainwater dilutes oceanic salinity). Both of these conditions contribute to buoyancy. A sharp temperature and density change - called the thermocline - floats about 100 meters below the surface, and marks the bottom of this warm "iceberg." The top layer of water may protrude 150 or more centimeters above sea level. This isn't so hard to picture if you think about tides, which also pile water up above sea level. El nino's energy reserve is vast, almost inconceivable."

As warm water squirts eastward across the pacific, it generates conditions which maintain its momentum, "El nino is prompted by a slackening of the trade winds which allows warm water to slosh back across the ocean, lowering the temperature of the warm pool and increasing the temperature of the central and eastern Pacific. Once started, the process is kept going by an intimate connection between oceanic and atmospheric conditions. The strength of the easterly winds is related to differences in atmospheric pressure across the Pacific ocean which, in turn, are related to differences in temperature in the underlying water. As the central and eastern Pacific warm, the air above it also heats up and becomes more similar in temperature to the air in the west. This causes the trade winds to weaken still further, allowing the continued influx of warm water. The climatic repercussions of this intricate interplay of the ocean and atmosphere are felt around the globe."

The movement of warm water across the pacific causes a reversal in the normal pacific weather conditions, ocean currents, and trade winds. The rains follow the movement of warm water and, as a consequence, the west pacific becomes drier whilst the east pacific becomes wetter, "As warm water moves eastwards, so does the rain, causing droughts in Indonesia, the Philippines and north-eastern Australia. Conversely, the normally dry western edge of south america experiences heavy rain."; "As the warm water builds up on the central and eastern sides of the pacific so wetter weather forms here rather than on the western side." Bunyard points out that at the start of the el nino in 1997, "The high pressure zone - bright weather and clear skies - now centred itself over south-east asia, while the low pressure zone - usually associated with monsoon rains - shifted to the deserts along the coast of peru, which is where the rain fell, thousands of miles way from its usual destination."

The reversal of weather conditions across the pacific affects the rest of the world .. "it was realized that el nino was responsible for climatic variations in a number of parts of the world. The current can interact with the atmosphere to reduce the seasonal monsoon air flows reaching india, thus causing drought in the subcontinent. The winds and the ocean somehow work in concert, depriving south asia of monsoonal rain. Disruption on this scale has a knock-on effect in other parts of the globe."; "During an el nino, the low pressure region .. shifts westward and instead of rising over the western amazon as it pushes up against the andes, it rises over the pacific ocean. Meanwhile, the high pressure branch, with cooler air, covers much of the amazon and reaches across to the west coast of africa."

Some el ninos do not die away after the warm water has crossed the pacific to the americas. Sometimes a second pool of water builds up again the following year creating what is called a double-peaked el nino, "Signs that the current el nino event might be waning following the peak in most indicators during the second half of 1997 proved short-lived. A "minor rally" occurred and, according to the assessment by the u.s. climate diagnostics center, has now mushroomed into a true second peak, surpassed only by the equivalent season’s peak during the record-breaking 1982/83 event. Current statistical and model forecasts suggest that the el nino event, and related patterns of temperature, rainfall and other weather anomalies, will persist until June 1998. The event will then weaken over the months of july to september."

The global impact of el nino is due firstly, to the huge scale of the area affected by the warm water as it streams 6,000 miles across the pacific and, secondly, to its impact on the Earth’s jet stream.

"It is because they hoard such stupendous quantities of energy that el ninos are second only to the change of seasons as shapers of global weather. Although el nino's water pooling phenomenon is regional, the effects this has on climate truly stretch around the world, as ocean currents and atmospheric winds ferry its monumental power out of the tropics and around the planet."

Jet streams are high altitude winds which blow at speeds up to 250mph, "The summertime jet stream is relatively weak; in the winter it’s much stronger because the poles cool down but the tropics stay relatively warm all year long. The position of the jet stream is dramatically important for local and regional climatic conditions, since it steers storms and separates tropical from polar air masses." One commentator has argued, "The movement of the tropical storms (caused by el ninos as it moves across the pacific) also disrupts the flow of the jet streams - strong, fast winds high in the atmosphere - which drive the world’s weather systems. El nino events have thus been linked with dry conditions in places as far afield as north-east Brazil, India, southern Africa and the Iberian Peninsula, with unseasonal warmth in western Canada and with a good chance of floods from Texas to Florida in North America." The huge pool of warm water releases water vapour which warms the atmosphere, "This atmospheric heating helps to determine the overall north-south temperature differences in both hemispheres, which significantly affects the strength and location of the mid-latitude jet stream winds over both the north and south pacific, primarily during the respective hemisphere's winter season. In these seasons, the jet stream is normally strongest over the western Pacific, and weaker east of the date line. These jet streams are a major factor controlling the weather patterns and storm tracks in the middle latitudes of both North and South America, with the largest impacts also occurring during the respective hemisphere's winter and spring seasons.."; "In response to the more uniform pattern of heating in the tropics during an el nino the wintertime jet streams in each hemisphere tend to be more zonally uniform and extend farther east than normal. However, the timing, location and magnitude of the ocean warming varies from one el nino to the next, which results in variations in the patterns of tropical rainfall and deep tropical heating. These conditions contribute to variations in the precise location, strength and structure of the mid-latitude jet streams over both the north and south pacific from one el nino to the next, and thus to the variability in weather patterns and storm tracks over North and South America."; "Dense tropical rainclouds distort the air flow aloft (5-10 miles above sea level) much as rocks distort the flow of a stream, or islands distort the winds that blow over them, but on a horizontal scale of thousands of miles. The waves in the air flow, in turn, determine the positions of the monsoons, and the storm tracks and belts of strong winds aloft (commonly referred to as jet streams) which separate warm and cold regions at the Earth's surface. In el nino years, when the rain area that is usually centered over indonesia and the far western pacific moves eastward into the central pacific, the waves in the flow aloft are affected, causing unseasonable weather over many regions of the globe.."

There are various explantions for this phenomena.

The most common explanation for el ninos is that they are caused by wind flows. Easterly trade winds pile up waters in south east asia but when these winds drop or reverse direction the pool of warm water spills back across the pacific, "El nino is prompted by a slackening of the trade winds which allows (the massive pool of) warm water to slosh back across the ocean, lowering the temperature of the warm pool and increasing the temperature of the central and eastern Pacific. Once started, the process is kept going by an intimate connection between oceanic and atmospheric conditions. The strength of the easterly winds is related to differences in atmospheric pressure across the Pacific ocean which, in turn, are related to differences in temperature in the underlying water. As the central and eastern Pacific warm, the air above it also heats up and becomes more similar in temperature to the air in the west. This causes the trade winds to weaken still further, allowing the continued influx of warm water. El nino conditions cease once the slightly cooler warm pool starts to heat up and the trade winds start to strengthen."; "Under "normal" conditions, easterly trade winds draw warm surface water away from the coast of Peru and Chile westwards. This allows cold water from the ocean depths to well up in the eastern Pacific while causing warm surface water to pile up in the west around Australia and the Philippines. The resulting warm pool is several degrees hotter and about a half metre higher than the eastern ocean. El nino is prompted by a slackening of the trade winds which allows warm water to slosh back across the ocean .."

Another explanation, but one which contains elements compatible with the previous explanation, is that the pool of warm water piled up in south east asia becomes lighter and more buoyant. This is because firstly .. "warm water is less dense than cool water" and, secondly, because the warm water triggers off heavy rains which dilute the salinity of the sea making it lighter than salt water .. "el nino waters are less salty than normal seawater" The water piled up on the western pacific becomes lighter and more buoyant, and then squirts across the pacific.

"The change begins with the distribution of atmospheric pressure over the indian and pacific oceans. This causes the intertropical convergence zone (ITCZ) to move further south than it usually does in the midwinter months of december to february. This is the southern oscillation and it causes the southern-hemisphere trade winds to weaken or even change direction. The wind driving the south equatorial current weakens or reverses, and so warm surface water begins to accumulate off south america, sometimes reinforced by water being driven by the wind from the west."

Some commentators believe el ninos may be triggered off by volcanic eruptions, "Some atmospheric scientists claim that aerosols ejected from volcanoes at mid-latitudes cause el ninos."; "Looking at the records of el nino this century, scientists can see that it has tended to follow volcanic eruption and submarine earthquake swarms."

"The prompt for this surprising development (the 1997 el nino) appears to have been Cyclone Justin which hovered off the queensland coast for nearly a month in march 25. Powerful winds generated by the rotation of the cyclone blew warm water normally trapped in the western Pacific eastwards."

"The great width of the pacific ocean is the main reason we see el nino southern oscillation events in that ocean as compared to the atlantic and indian Oceans. Most current theories of enso involve planetary scale equatorial waves. The time it takes these waves to cross the pacific is one of the factors that sets the time scale and amplitude of enso climate anomalies. The narrower width of the atlantic and indian oceans means the waves can cross those basins in less time, so that ocean adjusts more quickly to wind variations. Conversely, wind variations in the pacific ocean excites waves that take a long time to cross the basin, so that the pacific adjusts to wind variations more slowly. This slower adjustment time allows the ocean-atmosphere system to drift further from equilibrium than in the narrower atlantic or indian ocean, with the result that interannual climate anomalies (e.g. unusually warm or cold sea surface temperatures) are larger in the pacific."

"Scientists are divided on what triggers the buildup. Some say it begins when strong west-blowing winds near the equator - the trade winds - push against the sea, and drive sun-warmed surface waters against indonesia and australia. There the waters pile up like driftwood blown into a harbor. Others say that's backwards, that is an effect, not a cause; warm masses of air in the western pacific, heated by already-feverish tropical waters, create a vacuum beneath them as they rise like enormous hot air balloons. This vacuum sucks the trade winds toward it, making them stronger. Of course, these winds then pile more warm water up as they blow against the sea's surface, in turn causing more thermal updrafts, more vacuums, more winds. At some point, something snaps. The winds can no longer hold the wall of water up, and it begins flowing back "downhill." Like a teeter-totter, what was high becomes low, and what was low becomes high. Water levels actually dip below sea level near Australia, and as the pile traverses the Pacific, waters rise in the east near South America."

It seems strange that few scientists discuss enso events in terms of the oceanic conveyor belt. Most western climatologists are concerned about the oceanic conveyor belt in the north atlantic and make dire predictions about its global impact if it should stop, and yet they rarely seem to discuss the role of the conveyor belt in enso events, "According to scientists the uptake of Carbon dioxide from the atmosphere by the natural process of the gas dissolving in the cooling waters amounts to a staggering 105 billion tonnes a year. However, the reverse process of releasing it back again into the atmosphere occurs when the water resurfaces in the tropics. When the water on the conveyor re-emerges from the depths and is driven to the surface again it warms. As a result it releases a large part of its stored Carbon dioxide. At the moment it is calculated that the oceans remove about 3 billion tonnes more Carbon dioxide a year than they put back into the atmosphere."

"El nino results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. It is the internal dynamics of the coupled ocean-atmosphere system that determine the onset and termination of El nino events. The physical processes are complicated, but they involve unstable air-sea interaction and planetary scale oceanic waves. The system oscillates between warm (El nino) to neutral (or cold) conditions with a natural periodicity of roughly 3-4 years. External forcing from volcanic eruptions (submarine or terrestial) have no connnection with El nino. Nor do sunspots as far as we know."

The cause of el nino has not yet been unscrambled. It is not known why the westward moving, pacific ocean current reverses direction and pushes the current of warm water back towards the west coast of south america. It has been argued that, "There are other, more elaborate theories about what causes el nino, but one element seems common to all of them: when you look closely, you see a dog chasing its own tail. The truth is, no one knows what really causes el nino. It might very well be the last el nino that starts the next one. The official scientific name for el nino, enso (el nino-southern oscillation) reflects an understanding of this teeter-totter nature. An oscillation is a reverberation back and forth between two states, like between summer and winter. El nino is one extreme of a years-long oscillation in the entire pacific basin and the atmosphere above it. As the cycle unfolds, an "anti-El nino," dubbed la nina, appears as el nino disappears. Like a mirror image of el nino, it produces extreme weather and abnormal conditions in the western Pacific similar to those el nino produces in the east. Back and forth, east and west, this cycle has run continuously for many thousands of years."

El ninos tend to occur in cycles - there are periods of relative quiet followed by periods of greater activity.

It is used to be argued that el ninos occurred roughly every seven years, "El nino events used to occur approximately once every seven to ten years."; "El nino occurs every 3-8 years when the sea north of papua new guinea warms, reaching temperatures of 30C." The reasons for the longevity of this cycle are not known.

"Bruce Callander of the British Met Office says in a new report to the World Energy Council that in the past five centuries there have been only nine `very strong' El Ninos. All have been more than 20 years apart ..."

Period of high activity.

Period of low activity.

The recent el ninos haven’t followed the same cyclical frequency, "El nino's usually occur irregularly, approximately every two to seven years. The el nino years 1976-1977, 1982-1983, 1986-1987, 1991-1994, and are distinguished by large SST anomalies."; "After the 1982-83 humdinger, there was a minor respite, followed by el ninos in 1986-1987, and in an unusual break with tradition, 1990 to mid-1995, the longest in 130 years of record keeping."

One commentator has suggested that the latest occurrences of el ninos exhibit a range of new features, "The current El nino event is the latest in a sequence of unusual events and is symptomatic of a distinct change in behaviour dating back to the mid-1970s. Since then, el nino has been intensely active (relative to the previous 50 years). Although periods of high activity have occurred before, for example from 1880 to 1925, the recent period is distinctive in a number of respects. During recent times, el nino events have predominated and there are very few la nina events. This contrasts with a general tendency for el nino and la nina conditions to alternate every two to three years over the century as a whole. The period is further distinguished by the occurrence of the strongest event on record 1982-83 and of what, by some measures, is the longest el nino event on record - from 1990 to 1995."

The possible causes of el ninos have been highlighted above and yet any explanation has got to be able to explain the variations in el nino sequences that have occurred in the past. One commentator has suggested, "The massive and continuing destruction of tropical forests may be responsible for the abrupt change in the behaviour of el ninos. Tropical forests, particularly intact, are responsible for prodigous releases of energy in the form of water vapour into the atmosphere - equivalent to the energy that would be released by exploding some 5-6 million atomic bombs every day just over the amazon basin. Rainforests therefore appear to act as thermal machines and, above all, as regulators of atmospheric and oceanic systems which control the climate."

The scientific discovery of enso events is less than a couple of decades old and scientists are still learning about this phenomenon. Because of their limited knowledge, they are not yet capable of predicting when one will appear. It is not surprising they were unable to predict the 1982-83 el nino, "Even so, the 1982-83 el nino, widely recognized as the most severe of the 20th century, caught scientists by surprise. Unlike the el ninos of the previous three decades, it was not preceded by a period of stronger than normal easterlies on the equator, and it took place later in the calendar year than usual."; "Spring 1997 saw temperatures rising over the eastern Pacific Ocean. The apparent onset of El nino has confounded a number of the groups predicting the behaviour of this major cause of climate variation. As of March 1997, most models were forecasting only slight, if any, warming through the remainder of the year, and the statistical forecasts were in general agreement."; "The sheer strength of this El nino was unexpected, with most forecasters predicting either cool or only slightly warm conditions through to the middle of the year at least." One commentator seemed annoyed about this failure. He pointed out that scientists thought the next el nino would be in 1998, "If we can be as wrong as that, then we clearly have to question the basis of our understanding of what goes on in generating such a major switch in the world’s largest ocean." It is surprising that scientists’ understanding of el nino hasn’t improved since 1983 to enable them to predict what turned out to be the biggest el nino of the century,

Although el nino specialists failed to predict the emergence of the june 1997 el nino, once it had started they were able to predict with a fair degree of accuracy its climatic impacts on various countries around the world, "But although they did not predict it, they were able to fit it into a certain pattern. No weather like it had ever been seen before by u.s. meteorologists."; "Climate science is all about understanding probabilities. El nino is a climate phenomenon, and despite all the hype and dire predictions this el nino has generated, no one can say exactly what its effects will be. Scientists can, however, assign probabilities to its possible effects. Will California be deluged? There's a 60 percent chance of double the normal rainfall, and a 10 percent chance of triple. (There's also a 10 percent chance of drier than normal). Will Florida be cloudier and cooler than normal? There's a 70 percent chance the answer is yes. Will the Galapagos Islands be drenched? There's over a 95 percent chance that the answer is yes-a virtual certainty. What you see when you look at a probability map of el nino's effects is that, roughly, the closer you are to el nino's ground zero, which is the tropical pacific ocean, the higher the probabilities of predictable effects become. In north america, which is halfway between the equator and the pole, not many of el nino's predicted effects have higher than about a 60 percent probability."

The main predictions about el ninos are: "The new el nino will increase the risk of serious drought in australia, india, brazil and east africa. It will also heighten the danger of torrential rain and floods in american deserts from peru to california, and of Forest fires in indonesia." The further away that countries are from the pacific the more difficult it is to determine the impact that el nino will have on them, "Storms could batter britain this winter as a result of the asian smog crisis, an ecology expert warned yesterday. And the americas can expect even stronger winds, according to nick brown, of the oxford forestry institute."

"The effects of El nino can be devastating. During the 1877/78 event, between 9 and 13 million people died from hunger, disease and violence as crops failed in four provinces in northern China alone. A decade later, famine and epidemics resulted in 1.5 million deaths in India and the death of one-third of the population of Ethiopia."

The 1982-83 el nino was the worst on record - until the one in 1997-98, "The temperature change in 1982-83 reached 14C above normal in some places, the most extreme in recent years."; "The powerful el nino in 1982-83 inflicted an estimated £8.5 billion damage and claimed some 2,000 deaths." In 1982 .. "peru’s multi-million dollar anchovy industry was devastated .. During late summer, coastal areas of ecuador and peru began to suffer torrential rain, in some cases 300 times the normal annual rainfall. Continuing for eight months, the rains produced some of the worst floods this century. In the mid-pacific there was an abrupt rise in typhoons .. Across the pacific, in indonesia and australia, and across the indian ocean in southern africa, there was unprecedented drought and famine, by contrast. In australia .. some of the worst bush fires in the history of the world’ most fire-prone country .. destroyed property worth several thousand million dollars. .. In due course the drought spread to india, sri lanka, the philippines, hawaii and mexico. In december it was the turn of the united states (storms, tornados, floods, mudslides)."; "Forest fires are nothing new to indonesia. During 1982-83, fires swept through 3.6 million hectares of kalimantan. Smoke shrouded the area for more than four weeks, and the cost in lost timber stocks was estimated at more than $5 billion."; "In 1982 and 1983, el nino .. triggered forest fires in borneo that covered an area the size of belgium; typhoons were diverted onto new tracks, crashing into hawaii and tahiti; australia had its worst drought for a century and experienced massive wildlfires; california and the southern u.s. faced record storms and floods. Overall, the loss to the world economy from this one weather phenomena was put at more than $13 billion."; "U.S. crop losses from the 1982-83 El nino were projected to be in the neighborhood of $10-12 billion (Wilhite et al., 1987)."; "The economic impacts of the 1982-83 El nino, perhaps the strongest, event in recorded history, conservatively exceeded $8 billion world-wide, from droughts, fires, flooding and hurricanes (NOAA, 1994). Virtually every continent was affected by this strong event. Some 1000-2000 deaths have been blamed on the event and the disasters that accompanied it."

The 1997 el nino delayed seasonal monsoons over south east asia causing a prolonged drought in large parts of indonesia. This led to widespread starvation .. "the worst drought (in indonesia) since independence in 1945. Hundreds have been killed by food and water shortages and tens of millions of the 200 million population have seen their livelihoods shattered by months without rain."

It has been concluded, "It is this unprecedented demand for land - representing the aspirations of several million poor farmers, hundreds of logging and plantation companies and their employees, not to mention the oil and mining industries - coinciding with one of the most intense droughts on record, that has fanned the flames of this year’s fires in indonesia." Although landless peasants were responsible for setting many of the fires in Forests they had little other option when confronted by unjust land distribution. But they would never have had the opportunity to set fire to the Forests if multi-national oil, mining, and lumber companies hadn’t first blasted roads through them. In the wake of the logging and mining companies came slash and burn farmers burning down the Forests, "But without the logging companies, which had chopped down the big Trees and built the roads, they could never have done it."

The consequence of the massive Forest fires in indonesia was that during the summer of 1997 a vast smog the size of western europe settled over large parts of indonesia, malaysia, singapore, and the philippines, ‘El nino aggravated the smoke haze that blighted south-east asia in september and october; it created abnormally dry conditions that allowed forest fires to spread, and light winds trapped the pollution over the region.’ The smog was so thick that visibility dropped dramatically. Many died as a result of the fires and the smog .. "hundreds of people reported killed as the fires spread uncontrollably from borneo and sumatra, throwing a deadly blanket of smog over 70 million people in six countries: indonesia, singapore, malaysia, brunei, the philippines and thailand."

One commentator suggested the smog was caused mainly by the burning of Peatbogs rather than tropical Rainforests, "The forests of indonesia are burning again. Last year’s conflagration was briefly doused by monsoon rains in december. But with the rains faltering early in the new year, the country’s farmers and plantation owners have wasted no time in resuming their torching of the world’s second largest region of rainforest. .. the fires in the el nino years of 1982 and 1983 burnt more forest than last year’s and yet produced much less smoke .. It was the burning of these peatbogs, rather than the overall extent of the fires, that led to the intense smoke in neighbouring countries. These massive stores of organic material can burn for years, producing much more smoke than a conventional forest fire."

The area of Forest lost during the el nino was huge, "The total figure of forest, plantation and scrubland destroyed in Indonesia may have been as high as 1.5 million acres."; "Meanwhile the indonesian government has acknowldeged losing a further 75,000 hectares of tropical forest this year, in new outbreaks which have cost the economy an estimated £2 billion. These and nearby sudden flare ups in nearby sarawak are not new fires: they are a continuation of last year’s disaster, which had been smouldering away in the peat on the forest floor during the rainy season and have broken out anew as the rain stopped. This burning season, officially still even to begin, looks likely to repeat or surpass the appalling record of 1997, which environmentalists consider the worst year yet for tropical forest fires. Almost all of them were set by man and made worse by logging practices and mismanagement of vital resources." In july 1998 it was reported that, "Indonesia’s forgotten fires, which burnt on the island of borneo as the country’s economic and political systems went into meltdown this year, destroyed 30,000 square kilometres of forest - an area the size of belgium. This is almost six times the extent of previous official estimates, and bigger than the area burnt on the island during last summer’s heavily publicized fires. Some coal seams and peat bogs are still burning underground." In september that year it was suggested, "By november an area of land three times the size of britain had been affected. Up to 80% of the fires had been started deliberately to clear land for new plantations of oil palm and other commercial crops. What remains of the Forest is salvaged by loggers and carted away to be sold."

Since the 1970s some philippinos have started eating Snakes and, as a consequence, Rat numbers have increased signirifcantly. El nino made conditions even more favourable for Rats, "A Rat infestation unleashed by an el nino induced drought is ravaging rice crops in the northern philippines."

At the end of november 1997 some 300 Forest fires were raging in australia after abnormally high temperatures left many areas tinder dry.

"A massive shift of warm water into the central pacific has caused papua new guinea’s worst drought in half a century. The cooler water left behind does not generate enough clouds which normally bring up to 11 metres of rain each year to parts of p.n.g. On top of the drought, cloudless nights have caused severe frosts in highland areas, destroying crops. The crisis will damage papua new guinea’s economy. Mining , the country’s main earner, is already affected. Ore processing has stopped on 6 septemeber at the gold mine at porgera in the central highlands. Copper production stopped in mid-august at the ok tedi mine near the border with irian jaya."; "By September, drought and frost in papua new guinea had claimed at least 270 lives, causing many to flee from the highlands to the towns 30 - by october, more than 80,000 people risked starvation. The crisis is also hitting the economy. The Ok Tedi copper mine ground to a halt in august with the drying up of the fly river which supplies it with power and transport, while ore processing ceased at the porgera gold mine in september due to a lack of water to strip ore from rock. The australian government responded to pleas for help with a contribution of US$3.2 million to Papua New Guinea’s drought relief efforts, as well as technical assistance."; "As the current el nino event develops, impacts are being felt in many parts of the tropics and subtropics. By mid-year, Papua New Guinea was already experiencing severe drought. With no rainfall since March, the continuing drought has placed one million people at risk of starvation. In Irian Jaya over 400 people are reported to have died from malnutrition."

"Southern Vietnam was devastated by typhoon linda during the first two days of november 1997. Over 600 people are known to have died in the storm’s passing. There has been some speculation as to whether the typhoon was intensified by the extreme el nino event of 1997. In fact, the number of cyclones approaching the vietnamese coastline normally decreases during el nino events as the storm distribution over the western north pacific responds to the altered pattern of surface temperatures and winds. Was typhoon linda an abnormal response to an unusual el nino event or was it an isolated occurrence? The fact that the storm occurred during the closing months of what seems likely to be, world-wide, the warmest year on record also warrants consideration."

Droughts developed across large parts of south east asia, "At the same time, the convection that used to occur in southeast asia - the typical afternoon storm - is a lot drier. I’m talking about indonesia, the philippines, northern australia, new guinea, malaya, burma, getting into cambodia and vietnam." The drought also affected korea.

The economic damage caused by el nino made a big contribution to the economic stagnation that hit south east asia towards the end of 1997, "Economic damage from lost production in factories, lost foreign investors and reductions in tourists could also be massive. In September, one firm in Jakarta (Indonesia) reported a 40-50% reduction in tourists compared with last year 37. Neighbouring regions largely unaffected by the fires are similarly blighted - some hotels in Sabah (Malaysia) reported losing US$735,000 to US$800,000 during October. Grain production has been hit throughout the southern hemisphere and prices for some commodities, such as coffee, are expected to spiral."; "El Nino caused the worst drought in Indonesia for 50 years, setting off a chain reaction of crises, the report says. The rice crop failed, the price of imported rice quadrupled, the currency dropped by 80%, and riots erupted." Economic stagnation induced currency devaluation, "Since the de facto devaluation of the thai baht on july 2nd 1997, by early october, the philippine peso had lost nearly 35% of its dollar value, the thai baht about 42%, the malaysian ringgit 22%, and the indonesian rupiah 43%." These economic problems still persist, "During 1998, a dire financial flu swept across Asia. Banks collapsed, currencies nose-dived, decades of economic build-up were reversed." Unfortunately, the economic decline forced countries to try and exploit their resources even more rapidly in the hope of reversing the downturn.

In may 1998 the el nino climatic disaster, helped to bring about an economic collapse and economic mismanagement, which pushed people onto the streets and the rioting lead eventually to the overthrow of the dictator sukarno.

During the summer of 1997 the smog over south east asia became the global focus of concern, "Nick brown, of the oxford forestry institute said the asian dilemma was "a potent symbol to the rest of the world of what is going wrong with the environment." He said the burning of the rainforests was speeding up dangerous global warming." Unfortunately, the dramatic economic downturn in south east asia then began to distract attention from el nino and global burning even though the climate made a major contribution to the economic crisis.

"The urgent issue is how to check the worst fires in the region’s (brazil’s northern amazon rainforest) recent memory, which have eaten into a million hectares of highland savannah, an area the size of south-east england. Most of brazil’s fires have been started deliberately in the savannah country and spread to the forest. Local people have given up trying to control them and are pinning their hopes on rain."

By september (1997) storms were flooding central chile. El nino killed 17 and left 60,000 homeless. "Floods in chile in july were already the worst for a decade. (When an el nino occurs there is a build up of storm clouds over south america)."

El nino triggered off a hurricane which tore into shanty towns .. "the devastation yesterday after 115mph hurricane pauline (aka brutish coal) swept through the mexican resort of acapulco, leaving more than 300 feared dead. Cars were hurled on top of each other as roads turned into raging torrents. Dozens of trapped drivers drowned. Other victims were carried away by flash floods and mudslides or died in the wreckage of their collapsed homes. Last night, as authorities appealed for help, acapulco was declared a disaster zone. The resort has run out of fuel, drinking water, medicines and other essentials."; "The climate phenomenon known as el nino has contributed to the worst drought in memory. Combined with negligence and - in some cases - arson, it has made 1998 the worst year for fires since records began. In the first five months, there were more than 10,000 fires covering almost 1 million acreas. Mexico, one of the three most biodiverse countries in the world, has already lost more than 95% of its tropical forest. The mountainous 1.5 million acres of the chimalapas are among the few remaining pockets. What no one can explain is how fires began in remote jungle, as much as a week’s walking from the nearest communities."

The peruvian fishing industry collapsed bringing hardship to large numbers of people.; "Since the warm el nino current in the pacific poured a month of torrential rain, avalanches of mud and rocks, and flooding across peru, president alberto fujimori has barely spent a night in the presidential palace in lima. He has followed el nino’s trail of destruction across the country. The last time peru was hit in 1983, it cost several billion dollars in damage and left about 1,500 dead."; "Peru declared a state of emergency in 9 out of 24 of its regions." El nino also triggered off a huge increase in malaria leading to many deaths.

"El nino 1997-1998 continues to dominate climatic conditions causing extreme precipitation and severe storms in certain areas, and exceptionally dry conditions in others. El nino induced tremendous downpours in the coastal regions of Ecuador and northern Peru. Piura Peru had 12 separate days with at least half its normal annual rainfall, and Talara Peru received five times its normal annual rainfall in a single day. At the opposite extreme, Guyana, severely affected by drought, has begun water conservation measures, and gold mining has been severely affected by water shortages. Measures, based on el nino forecasts, have been put in place to minimize effects on the country's agriculture. Rain on Colombia's Pacific coast has increased the threat of landslides while inland the number of forest fires has risen, the loss reaching about 150 000 hectares. The sea level in the colombian pacific has risen 20 cm, fortunately without loss of human life thanks to accurate warnings."

.. "250mph tornadoes killed at least 39 people and left 120 missing, feared dead. Twelve killer twisters ripped through florida blowing hundreds of homes and businesses to bits. One was so fierce it left a 75 mile trail of destruction. Another wrecked everything in a 200 yard wide path for nine miles. Damage is expected to run into billions of pounds."; There were "severe thunderstorms and tornadoes across florida at the start of last week. At least 12 tornadoes were reported over a large area .. of central florida killing 39 people and destroying numerous homes, trees and power lines. In california, los angeles continues to be soaked by a succession of el nino related depressions. .. the running total (of rain) for the month was 340mm making it the wettest february since records began in 1877."; .. "the year the hoover dam overflowed. That was 1983, a year that saw a major el nino event. Whether this was coincidence or cause and effect, the guides won’t say."; "During stronger (enso) events, the United States experiences flooding and severe storms in some regions, and droughts and heat waves in other areas. Hurricane activity is usually minimal in the atlantic ocean, sparing the coastal areas from the gulf of mexico to the northeast. In the coastal west, the displacement of the jet stream can bring abnormally large amounts of rain and flooding to california, oregon and washington. During the summer, heat waves and below-normal precipitation bring drought, crop failures, and even death."

"Kenya has been particularly hard hit by (el nino induced) flooding, where rainfall surpluses since October have exceeded 1,000 mm in some parts. As a result, over 1,500 people have died of malaria spread by flooding."; "At least 300 people have died in northeast kenya from an illness that experts initially thought was anthrax. Thousands more are seriously ill. It has now been identified as the world’s worst outbreak of rift valley fever for two decades. Rift valley fever is a viral disease spread by mosquitoes. The kenyan outbreak was triggered by floods that brought burgeoning mosquito populations to the normally arid garissa and wajir districts. The people affected are among kenya’s poorest, and few have access to health care."

It is believed el nino also caused widespread flooding in somalia which killed 400. The floods lasted for a few months and covered huge areas of the country, "Torrential rains in November 1997 brought the worst flooding in more than three decades to Somalia, wracking the country and its people who have already had more than their share of civil wars and recurring droughts. The high magnitude of destruction and flooding from these torrential rains, the worse since 1960, have caused the death of thousands of people and have wiped out tens of thousands of livestock, farms and villages."

One commentator predicted the 1997 el nino might lead to winter storms in Britain. Several days of storms culminated, in the early hours of january 8th 1998, with a tornado which battered a small seaside village causing millions of pounds worth of damage, "Victims of a devastating 100mph tornado told of their terror as it ripped through a seaside town yesterday. In a few seconds it damaged more than 1,000 homes .. The freak twister, along with a hailstone storm, hit the sleepy west sussex town of selsey after midnight .. the tornado on its half mile trail of destruction .. 35 homes were hit by lightning." However, one local paper argued the event wasn’t unusual, "The coastal town (of selsey) was vulnerable to build-ups over the sea and in 1986 a slightly weaker tornado struck, causing damage to over 200 houses and leaving a path of destruction 70 metres wide." The following few days turned out to be the warmest on record, "Britain basked in its warmest january day ever yesterday. Temperatures in some parts of the u.k. hit 16.7C. The previous best january temperature was 14.5C in 1975."

"The el nino event of 1997/98 brought unprecedented climate stress to many parts of the world and its full impact is only now being assessed. As health statistics for 1997 are analysed, the World Health Organization (WHO) reports that nearly 150,000 cases of cholera were reported that year with heavy rains in africa, linked to el nino, thought responsible for around 80 per cent of the total. Fatality rates reached 20 per cent in some countries."; "For the second time in six months, the world is glimpsing the health consequences of escalating climate change. After triggering the choking havoc of smoke from Indonesian forest fires last autumn, the worst El Nino for 50 years has in the past two months unleashed plagues of disease across east Africa in the wake of unprecedented dry-season rains and floods. Cholera and malaria have claimed record numbers of victims across Kenya, Tanzania, Uganda and Somalia. Pests, such as a toxic insect known as the Nairobi fly, have proliferated. Locusts may be on the way. But most frightening of all comes an outbreak of Rift Valley Fever, a cattle disease that has decimated herds across eastern Kenya and southern Somalia and jumped the species barrier to kill hundreds of humans. It attacks with such ferocity that medics at first feared an outbreak of anthrax, and now speculate that they may have seen the emergence of a new super-strain of the virus that could take permanent residence in humans. Samples of blood collected by Martin and analysed in South Africa and Kenya revealed the Rift Valley Fever virus in both animals and humans. Last week, the Red Cross said the virus had killed `more than 450 people' so far and remained out of control. With dozens of settlements in the flooded region still not contacted, Martin refuses to be drawn on the death toll. Some suggest several thousand may be dead. And things could be even worse over the border in Somalia, a land without any form of central government. The disease has invaded a rural population without medical help and already severely weakened by malnutrition, TB, malaria and a range of parasitic diseases. The disease was first identified in 1931 in the Rift Valley in Kenya - hence its name. Until now, the largest known outbreak in humans was in Egypt during floods in 1977, when 600 people died. Some researchers have suggested the virus could have been responsible for Biblical plagues in Egypt. "

"Nigel dudley, who wrote a report on Forest fires last year for the wwf, says: "El nino has undoubtedly made a bad problem worse, and climate change appears to be making el nino more severe and more frequent so we have to do something." And there is evidence that the breakdown in law and order all over the world is making matters worse. Although south-east asian smog caught the headlines last year and north east brazil is now the centre of attention, there were devastating fires in nine other major forest countries last year. The worst hit countries were papua new guinea, colombia, peru, tanzania, kenya, rwanda, australia, china and russia. In europe, france, greece, italy, portugal and spain lost large areas of already scarce temperate forest." It has been estimated that, "The forest fires of late 1997 emitted about a billion tonnes of carbon dioxide, more than is produced by automobiles and power stations in western Europe over a year."

Oliver morton believes, "The el nino currently under way is the biggest on record, and is already causing havoc: crop failure in southern africa, storms in santa monica, failed monsoons across asia." In the view of jacqueline karas, "As the impacts of what may be prove to be the strongest El nino event this century start to bite across the world, there is growing evidence that we may be beginning to witness the effects of human-induced climate change."

El ninos do not cause only damage. In many cases the flooding they cause results in a massive explosion in the growth of Phytomass, "Satellite images recorded last year showed the greening and the flowing of the atacama desert to be the most extensive in 60 years thanks to el nino rains."

"When el nino ends, cold waters upwell around the pacific’s coral reefs. These waters are rich in nutrients, and so creatures multiply. Among these are the sea urchins and the crown of thorns starfish which eat corals faster than they can multiply: even the atolls of the equatorial pacific are at risk from el nino’s backswing."

"The current el nino is shaping up to be at least as severe as the devastating event of 1982-83. There are already signs that the wildlife catastrophe of 1982-83 (in the galapagos islands) may be about to repeat itself. Many seabirds have failed to nest, including the waved albatrosses. A shift from green to red algae is in progress, and hammerhead sharks have moved into deeper, cooler water."

It is suggested that global burning may be responsible for the prolonged and ferocious series of el ninos that have occurred since the mid 1970s. Whilst the link seems obvious it has not been proven.

According to report commissioned by greenpeace and written by jacqueline karas, "A second possible explanation for recent events is the warmer background conditions that have prevailed over this time. The unusual behaviour of el nino since the mid-1970s coincides with a sharp rise in global air temperatures. The 1980s was the warmest decade on record (back to 1860), while 1995 was the warmest year on record. In july this year, david parker of the u.k. meteorological office further predicted that 1997 will also be exceptionally warm. As air temperatures have risen, so have those of the tropical Pacific. In a new study of pacific sea surface temperatures, knutson and manabe find a warming trend over a large part of the equatorial pacific over the past century. This trend has accelerated in recent decades. Since the 1970s temperatures have risen at a rate of 2.9oC per 100 years - this is more than twice the rate of change found over the previous 20 years. Part of this warming is due to high levels of el nino activity - el nino events coincide with warming of the lower atmosphere in the tropics of close to 1C. But the existence of a long-term warming trend in both global and sea surface temperatures points to an underlying change in background state of the pacific ocean."; "The current event (the el nino of 1997-98) is the latest example of a distinct change in the behaviour of el ninos dating back to the mid-1970s. While these events could have occurred naturally, there is growing evidence that we may be starting to witness the effects of climate change induced by rising concentrations of greenhouse gases."

According to mick kelly, el ninos may be a part of the Earth’s climate regulation system, "It could be like a pressure valve, acting as a regulator controlling the planet’s temperature, so that it never gets too hot or too cold."

Tim radford claims that richard feely has discovered the link between global warming and el ninos but on closer inspection this doesn’t amount to much of a breakthrough, "Until now, nobody has been able to connect it (el nino) directly to global warming. But Richard Feely, a scientist at the US National Ocean and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, Washington, has finally made the link. Today in the journal Nature he reports that during the years 1991-94, the amount of carbon dioxide that went from the oceans to the atmosphere was between 30 per cent and 80 per cent less than in the normal - non-El Nino - year of 1996."

Radford puts a radical spin on some research by bruce callander, "Bruce Callander of the British Met Office says in a new report to the World Energy Council that in the past five centuries there have been only nine `very strong' El Ninos. All have been more than 20 years apart except the last two which were in 1982-83 and 1997-98. Nine of the 10 hottest years ever recorded have been since 1982, and the hottest ever was 1998: during the height of an El Nino."

"These violent storms are rising because the area of ocean with temperatures above 27C has expanded considerably over the past forty years."

There is much less controversy about the reverse proposition - that el ninos are helping to boost global burning. El nino is such a massive phenomenon affecting the entire tropics that it is bound to have an impact on the global climate but thus on global temperatures.

It has been argued that, "Six of the warmest years on record were in the 1980s, and they can be correlated with the flow of el nino "

La nina is the reverse of el nino. La nina events do not exist in their own right - they occur only after an el nino, "As the central and eastern Pacific warm, the air above it also heats up and becomes more similar in temperature to the air in the west. This causes the trade winds to weaken still further, allowing the continued influx of warm water. El nino conditions cease once the slightly cooler warm pool starts to heat up and the trade winds start to strengthen. This sets the stage for transition to La Nina - or cold - conditions in the central and eastern Pacific, during which the process in reversed."; "La Nina is characterized by unusually cold ocean temperatures in the equatorial pacific, as compared to el nino, which is characterized by unusually warm ocean temperatures in the equatorial pacific. Global climate anomalies associated with la nina tend to be opposite those of el nino."; "La nina is the opposite phase of the phenomenon with warm temperatures in the equatorial Pacific replaced by cool and the nature of the climate disruption elsewhere in the tropics and sub-tropics reversed. Usually, there is some respite between the two phases but there are indications that la nina may, this time round, follow hard on the heels of the record-breaking el nino event." However, el ninos are not always followed by a la nina.

"During recent times, el nino events have predominated and there are very few la nina events. This contrasts with a general tendency for el nino and la nina conditions to alternate every two to three years over the century as a whole."

"In 1988-1989, there was a la nina, which occurs after some (but not all) el nino years."

"Suddenly during May of 1998, the warm waters of El Nino were replaced by the cold water phenomenon known as La Nina which has persisted till now. Historically, another consequence of La Nina is an increase in the number of hurricanes that make landfall in the U.S. The two hurricanes that made landfall and caused the disastrous flooding along the North Carolina coast are consistent with that trend."

It was pointed out that scientists failed to predict the occurrence of the last 1997-98 el nino. However, just as it possible to predict roughly what types of impacts that el nino will have when it arrives so the same is true for la ninas, "La Nina brings wet weather and flooding to Southeast Asia and parts of Australia, drought to the US west coast and South America and can lead to an increase in tropical storms in some areas."

"The latest data regarding conditions in the equatorial pacific ocean show that the el nino event of 1997/98 has passed its peak and there is evidence that the next la nina, el nino’s mirror image, may follow more swiftly than usual. Lars olsson of the World Climate Programme warned that "La Nina is developing rapidly. This one seems more intensive than what we have seen before." The swift arrival of la nina could compound existing problems, "After severe droughts the top soil is very fragile and if you get heavy rain on the top soil, then you could get heavy erosion," Olsson pointed out. La nina may, however, bring an end to widespread forest fires and smog in Southeast Asia."

Hurricane mitch devastated virtually the whole of honduras as well as large parts of nicaragua, and is believed to be the biggest atlantic hurricane for two centuries, "Hurricane Mitch killed more people than any storm in the western world for 200 years. It was the fourth fiercest hurricane in the Caribbean this century. When it turned inland and stalled for two days over the mountains of central Honduras, it picked its spot with deadly skill. Forced to rise 2000 metres, it cooled and dumped huge amounts of moisture picked up from the sea. Over two days, some 40 cubic kilometres of water fell on Honduras and neighbouring areas of Nicaragua and El Salvador - three-quarters of what normally falls in a whole year. Mitch has changed the landscape of parts of Central America forever."

"Like other forecasters, mark jury says that the root cause of the floods (in mozambique) was la nina - a cold water oscillation in the equatorial pacific - which is now at full force. In 8 out of 10 years when la nina is active, says david parker at britain’s meteorological office in bracknell, it brings above average rains to south east africa. (But jury argues this year was exceptional because weather conditions over the indian ocean amplified la nina’s impact). Normally, cyclones and other weather systems coming west across the indian ocean are diverted south, away from land, by a jet stream heading the other way. "But this year the jet stream was weak and the storms came right on through," says jury. Jury says that if dam managers on the limpopo had taken more notice of the warnings by him and others, the flooding could have been reduced. "They have been keeping their reservoirs too full." he says. Managers contributed to the floods by emptying their dams in a panic as the rivers filled. "They should have started to empty them much earlier," jury says."

Some commentators have speculated about links between el ninos and the decline in hurricane activity in the atlantic. It has been argued that during el ninos, "Hurricane activity is usually minimal in the atlantic ocean, sparing the coastal areas from the gulf of mexico to the northeast." Jeremy leggett seems to agree. He points out that el nino was at its height in late 1997, "Yet in the atlantic it was the quietest hurricane season in years, as would be expected in a strong el nino year." William gray suggests there is a link between rainfall in the sahel and the hurricanes hitting the united states .. "forecasts are built round the strong association of rainfall in the sahel region of west africa and the number of intense hurricanes that hit the united states. The hurricane season in the atlantic starts in earnest at the beginning of august and runs to around the end of october." This link could involve el nino to the extent that it influences rainfall in the sahel. However, it has been pointed out that, "The 1997-98 el nino took hold in the late summer and autumn of 1997. It spawned hurricane pauline that hit the southwest of mexico early in september." Jeff hecht argues, "During an el nino, when warm surface waters appear in the east pacific, the number of atlantic storms stays low because of changes in high altitude winds. (El ninos produce strong winds in the stratosphere which blow away the tops of the atlantic hurricanes preventing them from forming)."

The reverse may be true as regards la ninas which might increase hurricane activity in the atlantic. "Dr. William Gray and his team at Colorado State University recently issued their forecast for the 2000 Atlantic tropical season. They predict 11 tropical storms in the Atlantic. Seven of them, the forecasters believe, will become hurricanes. And three of these are expected to be intense. Dr. Gray's forecast indicates a hurricane season about 25 percent more active than the average for the last 40 years. This season will be enhanced by weak La Nina conditions in the tropical Pacific. That forecast is ominous."

The counterpart of the southern oscillation in the pacific is the northern oscillation in the atlantic, "El nino’s cousin is called the north atlantic oscillation. Changes in the nao correlate with all sorts of variables around the ocean, from rainfall in bordeaux to the amount of saharan dust that ends up in the bahamas and the richness of fisheries off iceland. The nao affects the circulation of the seas at the north atlantic’s margins. It leaves smudgy cyclonic fingerprints all over the northern hemisphere’s climate. In terms of measurement, the nao is a fairly simple thing - it is an index created by comparing the pressures in the azores and in iceland. In the first half of the 20th century meteorologist created a number of similar oscillating indexes. The southern oscillation, the difference between the pressure in darwin and in tahiti, measures the atmospheric component of the el nino egffect, which is why (it is called) enso - el nino/southern oscillation. For the nao, a high index signifies low pressure around iceland and the reverse off portugal, a situation that gives rise to strong westerly winds. In winter - which is when the nao’s signal is strongest - these westerlies bring heat from the ocean’s surface into the european continent, along with storms .. So a high index tends to mean relative warmth in northern europe, while a low index mean weak westerly winds and a continental climate dominated by cold air from the north and east. The nao doesn’t just jiggle about on a timescale of weeks and months, it also has slower rhythms whose beats are measured in years, decades or more. These long term changes suggest that something more than atmospheric chaos is going on. .. the shift from very low nao indexes in the 1960s to consistently high indexes in the 1990s." (When the nao is high and strong westerly winds pass over the labrador sea, it cools the water which thus sinks to the sea floor. At the same time the westerlies don’t reach the greenland sea which gets warm, and thus less salty thereby reducing convection. When the nao is low the reverse applies. Winds from the north pole cool the greenland sea and bring about convection whereas .. ). "The same winds drive relatively fresh water and sea ice down the east coast of greenland, round its tip into the labrador sea, where the freshness and lack of cooling winds make deep convection less and less likely. A long term shift in the climate towards low naos and cold european winters should, if dickson is right, shift the production of cool, deep water from the labrador sea to the greenland sea."; "When there is a strong westerly circulation, the pressure difference is large with a deep depression extending from the Azores to the mediterranean. A blocked circulation will tend to exhibit the reverse situation with high pressure near greenland or over scandinavia and low pressure systems running into the mediterranean."

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