Antinuclear

Australian news, and some related international items

El Tío – a new and worrying twist in the causes of global warnming

climate-changehighly-recommendedMeet El Niño’s cranky uncle that could send global warming into hyperdrive, The Conversation, Research Fellow in Climate and Water Resources, University of Melbourne, Climate Extremes Research Fellow, University of Melbourne                                 , Science Fellow, Met Office Hadley Centre   Professor of Atmospheric Science, University of MelbourneSenior Research Scientist, CSIRO, PhD student, University of Melbourne      February 6, 2017

You’ve probably heard about El Niño, the climate system that brings dry and often hotter weather to Australia over summer.

You might also know that climate change is likely to intensify drought conditions, which is one of the reasons climate scientists keep talking about the desperate need to reduce greenhouse gas emissions, and the damaging consequences if we don’t.

El Niño is driven by changes in the Pacific Ocean, and shifts around with its opposite, La Niña, every 2-7 years, in a cycle known as the El Niño Southern Oscillation or ENSO.

But that’s only part of the story. There’s another important piece of nature’s puzzle in the Pacific Ocean that isn’t often discussed.

It’s called the Interdecadal Pacific Oscillation, or IPO, a name coined by a study which examined how Australia’s rainfall, temperature, river flow and crop yields changed over decades.

Since El Niño means “the boy” in Spanish, and La Niña “the girl”, we could call the warm phase of the IPO “El Tío” (the uncle) and the negative phase “La Tía” (the auntie).

These erratic relatives are hard to predict. El Tío and La Tía phases have been compared to a stumbling drunk. And honestly, can anyone predict what a drunk uncle will say at a family gathering?

What is El Tío?

Like ENSO, the IPO is related to the movement of warm water around the Pacific Ocean. Begrudgingly, it shifts its enormous backside around the great Pacific bathtub every 10-30 years, much longer than the 2-7 years of ENSO.

The IPO’s pattern is similar to ENSO, which has led climate scientists to think that the two are strongly linked. But the IPO operates on much longer timescales.

We don’t yet have conclusive knowledge of whether the IPO is a specific climate mechanism, and there is a strong school of thought which proposes that it is a combination of several different mechanisms in the ocean and the atmosphere.

Despite these mysteries, we know that the IPO had an influence on the global warming “hiatus” – the apparent slowdown in global temperature increases over the early 2000s……….

Since about the year 2000, some of the excess heat trapped by greenhouse gases has been getting buried in the deep Pacific Ocean, leading to a slowdown in global warming over about the last 15 years. It appears as though we have a kind auntie, La Tía perhaps, who has been cushioning the blow of global warming. For the time being, anyway.

The flip side of our kind auntie is our bad-tempered uncle, El Tío. He is partly responsible for periods of accelerated warming, like the period from the late 1970s to the late 1990s.

The IPO has been in its “kind auntie” phase for well over a decade now. But the IPO could be about to flip over to El Tío. If that happens, it is not good news for global temperatures – they will accelerate upwards……….

more work needs to be done to predict the next shift in the IPO and climate change. This is the topic of a new set of experiments that are going to be part the next round of climate model comparisons.

With further model development and new observations of the deep ocean available since 2005, scientists will be able to more easily answer some of these important questions.

Whatever the case, cranky old El Tío is waiting just around the corner. His big stick is poised, ready to give us a massive hiding: a swift rise in global temperatures over the coming decades. https://theconversation.com/meet-el-ninos-cranky-uncle-that-could-send-global-warming-into-hyperdrive-72360

 

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February 6, 2017 - Posted by | climate change - global warming

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