The ell Nino is here

It’s Here: Japan Meteorological Agency Declares El Nino

Denial Crock of the Week.

10 December, 2014

So, it’s here.

Predictions that were made in the spring projected a possibly huge El Nino, on the scale of the historic 1998 event, which would put global temperatures into overdrive. What we’re getting seems, so far, to be somewhat more of a moderate cycle, but with the potential to make 2015 a record breaking year for global temperatures, whether 2014 sets a new record or not.

Above, good recap of what an El Nino is and why its important.

Reuters:

Japan’s weather bureau said on Wednesday that an El Niño weather pattern, which can trigger drought in some parts of the world while causing flooding in others, had emerged during the summer for the first time in five years and was likely to continue into winter.

That marks the first declaration by a major meteorological bureau of the much-feared El Niño phenomenon, which had been widely expected to emerge this year.

El Niño – a warming of sea-surface temperatures in the Pacific – can prompt drought in south-east Asia and Australia and heavy rains in South America, hitting production of food such as rice, wheat and sugar.

The Japan Meteorological Agency (JMA) forecast last month that the possibility of an El Niño pattern forming this winter was higher than the 50% it had projected in its previous monthly prediction.

But on Wednesday it said that an El Niño had emerged between June and August, continuing into November.

“We can’t tell whether or not El Niño will continue until spring, but we can say that there is a higher chance of it continuing in the winter,” said Ikuo Yoshikawa, a JMA forecaster.

Here, my spring, 2014, interview with Kevin Trenberth of the National Center for Atmospheric Research in Boulder, on signs of a new El Nino, and the “PDO”, the Pacific Decadal Oscillation, which is another big driver of global weather and global temperatures
.

Reporting Climate Science:

Leading climate scientist Kevin Trenberth has toldreportingclimatescience.com that he believes the pause in global warming may be caused by long term changes in the Pacific Ocean.

Trenberth and colleague John Fasullo argue in a new scientific paper that the massive El Nino Pacific Ocean warming event that occurred in 1997 and 1998 triggered the pause. They say that the El Nino caused a large loss of heat from the deep ocean to the sea surface that resulted in a cooling of the oceans. Since then the deep ocean has been absorbing heat back from the upper ocean and so cooling the atmosphere.

The implication is that the heat being absorbed from the atmosphere by the oceans has offset the underlying and ongoing warming of the atmosphere due to green house gases. As the deep ocean waters have slowly warmed they have taken heat from the upper ocean which has then cooled the atmosphere. This is the cause of the apparent hiatus in global warming that has manifested itself as a halt in the rise in global mean atmospheric temperatures seen in the second half of the 20th century.

Trenberth and Fasullo, from the US National Center for Atmospheric Research in Boulder Colorado, suggest that long term oscillations in the Pacific Ocean, known as Pacific Decadal Oscillations (or PDOs) drive alternate 20-plus year cycles of upper ocean warming and cooling which also involve heat being exchanged with the atmosphere. The implication of this is that when the Pacific is in a negative phase the upper ocean loses heat and so cools the atmosphere, and that when it is in a positive phase the upper ocean warms and so heats the atmosphere.

“It is not so much that the atmosphere warms up rather that the upper levels of sea get warmer and these interact more directly with the atmosphere,” Trenberth said. So a warmer sea surface leads to a warmer atmosphere. “More heat penetrates to the deep ocean in the negative phase and that is not the case in the positive phase,” he explained.

“We can speculate that the huge 1997–1998 El Niño event was a trigger for the change in the PDO; certainly, it led to a large loss of heat in the Pacific… that has taken years to recover from, if the recovery is even complete. Past behavior of the PDO… suggests that regimes can last for 25 years,” Trenberth and Fasullo write in their paper.

“The picture emerging is one where the positive phase of the PDO from 1976 to 1998 enhanced the surface warming somewhat by reducing the amount of heat sequestered by the deep ocean, while the negative phase of the PDO is one where more heat gets deposited at greater depths, contributing to the overall warming of the oceans but cooling the surface somewhat. The Pacific Ocean appears to account for the majority of the decadal variability… Nevertheless, the events in the Pacific undoubtedly also affect the Atlantic, Indian, and Southern Oceans as the system acts collectively to equilibrate to these changes in the flow of energy,” they write.

The paper, entitled “An apparent hiatus in global warming?”, appears the new scientific journal Earth Futures.

“There are really deep teleconnections between the Pacific and the Atlantic and Southern Oceans,” Trenberth explained. “The centre of action is the Pacific Ocean but the main places where heat goes deep into the ocean are the Atlantic and Southern Oceans rather than the Pacific.”

There is also a very strong relationship with winds and sea level, according to Trenberth. Water is piling up in the western Pacific Ocean at a rate of around 10mm per year which is three times the global average. This has led to a difference in sea level, measured by satellite radars, between the western and eastern Pacific. “The sea level is 20cm higher in the western Pacific and the only way to keep it there is for strong winds to pile up the water. It is these changes in the winds that change the ocean currents and affect where the heat is going,” he explained. “But this can’t keep going for ever. The ocean wants to slop back to the east.”

Bloomberg:

El Ninos, which are caused by the periodic warming of the Pacific, occur every two to seven years and are associated with warmer-than-average years. Since the last El Nino, the Pacific has either been in its cooler state, called La Nina, or neutral. The event can bring milder winters to the northern U.S. as well as drier conditions to parts of Australia, Indonesiaand northeastern Brazil.

Tropical Pacific temperatures have exceeded El Nino levels for a month and the Southern Oscillation Index, which indicates the development and intensity of El Nino or La Nina events, has remained at or near thresholds for three months, Australia’s Bureau of Meteorology said on Dec. 2. Patterns are consistent with a weak event developing, New Zealand’s National Institute of Water & Atmospheric Research said separately that day.

“Regardless of whether an El Nino is declared, El Nino-like effects are likely,” Australia’s bureau said in the fortnightly update, citing impacts already seen in the country as well as in Asia, South America and southernAfrica. The bureau maintained at least a 70 percent chance that an event will be declared in the coming months.