El Niño is coming back

Some guests are unwelcome but necessary. Flies are a nuisance but they serve a useful purpose. Strange weather events that happen every few years bring good and bad consequences. After an absence of three years El Niño is back, bringing good things for some and bad things for others.

Scientists at the National Oceanic and Atmospheric Administration (NOAA) announced that El Niño, the periodic warming of the central and eastern tropical waters around the coast of Ecuador, Peru and Chile, which comes every two to five years and usually lasts for about a year has happened again. Measuring ocean temperatures shows that the surface temperature is at least one degree above the normal sea surface temperature in the El Niño zone, and it looks as though the sea temperature is getting warmer.

We understand what causes the El Niño. The prevailing wind along the equatorial region is from east to west. This moves water to the western parts of the pacific, blowing it along until it is on average piled about a metre higher than normal. To replace the water blown from the surface of the ocean in the east deeper water is dragged up, which means that the eastern pacific will be around 22 degrees Celsius in daytime while the western ocean will be eight or so degrees warmer.

All this is the normal pattern; However in an event, the winds El Niño die down a bit, some of the warm water that was heading westwards stays or returns eastwards and the eastern pacific ocean gets warmer. The warmer ocean makes the winds even weaker, which makes the ocean even warmer. So El Niño (the little child) grows.

An El Niño Southern Oscillation causes warmer but nutrient poor waters to replace cooler but nutrient rich seas. The event also causes changes in climate over much of the world, from Australia to South Africa via South America, and reaching up to the whole of North America and parts of Western Europe.

Officially the El Niño event exists when there is a half degree Celsius warmer than normal average sea temperature (as measured by certain methods). So we now have an official El Niño event. NOAA has now confirmed that the average temperature is more than one degree Celsius in the El Niño zone.

One degree warmer sea surface temperature does not sound much, but such is the complex inter-relations of our planet’s climate that one degree makes a lot of difference to a billion people. Typically the El Niño event will have various effects upon virtually all of us.

Here are the most significant effects of the warmer seas and oscillations we call El Niño:-

  1. Air pressure rises over the Indian Ocean, Australia and Indonesia while air pressure falls over Tahiti and the South America Pacific Coast
  2. Trade winds weaken but the Peruvian desert gets rainfall.
  3. As the warm water spreads eastwards it carries the rain, causing drought in the Western Pacific and heavier than normal rainfall in the Eastern Pacific.
  4. There are fewer fish around the coast of South America and the fishing industry suffers.
  5. There will be fewer hurricanes around the Eastern part of the USA, and warmer sinters in Northern USA and more rain in Florida, reducing the risk of wild fires.
  6. The dry parts of South West USA will get more rainfall than usual; they will welcome this.
  7.  There may be flooding in Central America, drought in Indonesia and storms in California.
  8. In Europe the summer may be hotter than normal.

After about a year El Niño wears itself out, with the ocean waves dispersing the heat so it ends up back to its original situation, which of course is where the next El Niño event will start from.

These conditions that I have described will probably start soon (sorry I cannot be more precise) and last about a year. These are normal events and as far as we know the planet has hosted El Niño for millennia.

You will see that these events are caused by heat moving from one part of the ocean to another part. The extra heat moving is apparently small but thermodynamically the surface of an ocean temperature the size of Europe being raised by a degree Celsius requires the movement of a great deal of heat.

I do not how El Niño will react to the expected future of warmer sea conditions as a result of climate change and I think no one knows. The El Niño events are becoming “stronger”, it would seem, each year. It may simply end there with longer and stronger events bringing the consequences that I have described.

However there is another possibility; the warming of the seas may give rise to completely different climatic cycles. They will almost certainly be bad for mankind because humanity has but its structures on places which have specific known climates; we farm where there is irrigation and soil; we build cities near coasts or on rivers; we fish where there are seas full of fish. Changing the fundamentals will inevitably bring fundamental change.

3 Responses

  1. The return of El Niño, recorded, I read, on June 17, may be part fo a really worsening situation. Yesterday, The Guardian carried this story, “World will warm faster than predicted in next five years, study warns.”
    http://www.guardian.co.uk/environment/2009/jul/27/world-warming-faster-study
    The subtitle of the article is,”New estimate based on the forthcoming upturn in solar activity and El Niño southern oscillation cycles is expected to silence global warming sceptics.”
    As you might expect, the skeptics are all over this article, like flies, in the comments.

  2. My neighbour has been doing detailed records of our local weather patterns for over 25 years now and the findings are that of less and less sun exposure year in year out,
    at the same time we have had much more water during both winter and summer and the earth is now at its lowest activity for the same period.

    If the sun is about to reactivate again we will son know how warm the earth will become.

    Since 1992 all new cars have had a C A T fitted, who’s main aim is to convert Carbon Monoxide into the main greenhouse gas, how convenient is that.

    At the very bottom of our oceans is what’s called the benthic layer, this area is at a constant temrature of around 4 degrees, and many plancton exist here and we know that these are vital for life, our oxygen emminates from here, upset this stage and we are at the mercy of our life blood.

    We need to start looking at what is happening here, it all adds to any changes.

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