Recent reports about the potential for a “significant” El Nino and the effect this would have on weather in the United States have specifically focused on whether this might be the answer everyone is looking for to solve the severe drought whose effects are being felt across California, which is also currently being ravaged by serious wildfires. The 2015 Sierra Nevada snowpack is at a 500-year record low.
While there are indications that we are in the beginning phase of an El Nino, and it is true that the last very strong El Nino of 1998 brought lots of rain to California, it isn’t typical of all El Nino’s and the exact characteristics are hard to predict, yet there is even more reason to doubt its potential to be a “drought solver” which we will explore here. But aside from that, it is important to emphasize that a strong El Nino can bring dangerous weather conditions to other areas, such as the prolonged severe Northeast ice storm of 1998, thought to be linked to El Nino, and, as we are often reminded, intense bouts of precipitation are not necessarily ideal and can even be fatal.
But it is the case that well-established weather phenomena like the El Nino Southern Oscillation have a more concrete effect than any amount of carbon dioxide, and it can certainly remind us that the frenzy around anthropogenic global warming doesn’t account for these natural cycles which do affect weather, storms, and climate. However, will it solve the drought? Let’s spend some time on this question.
NATURAL CAUSES OF CLIMATE CHANGE
In a white paper I recently reviewed by Joseph D’Aleo, former director of meteorology for the Weather Channel, he dismisses the case for carbon dioxide-driven warming, as many well-qualified scientists have done.
The factors and cycles he discusses as actually significant are the following:
1) Solar cycles
2) Longer term ocean cycles: Atlantic Multidecadal Oscillation (AMO) / Pacific Decadal Oscillation (PDO)
3) Volcanic activity
4) Shorter term ocean cycles: El Nino Southern Oscillation (ENSO)
More about these:
→ As far as solar cycles, there is the well known 11-year solar cycle, as well as an apparent 200-year cycle called the “De Vries” cycle, also called the Suess cycle (for more on the role that the Sun plays, check out D’Aleo’s white paper or some of the references in the above-cited blog).
→ Two ~60 year ocean temperature cycles, the AMO and PDO, slightly out of phase, each with a warm/positive and cool/negative phase.
AMO Pattern by Wikiuser Giorgiogp2. Warm phase.
PDO Pattern by Wikiuser Giorgiogp2. Warm phase.
→ Large volcanic eruptions pump tons of aerosols and material into the sky, and there is good reason to think this can significantly affect climate. Some say that the 1816 “Year Without A Summer” resulted from not only declining solar activity of the Dalton Minimum, but the eruption of Mt. Tambora in Indonesia
→ And there is the El-Nino Southern Oscillation, described as a shorter term PDO, by D’ Aleo.
Professor Carl-Otto Weiss, at a recent conference of the Schiller Institute in Paris, had a very similar discussion of these factorsin his presentation there. In the graphic below from his presentation, he shows how a 65-year temperature cycle made by combining the AMO/PDO and the longer 200+ year solar cycle mirror temperature changes since 1850, with shorter term fluctuations being accounted for most significantly by volcanic eruptions and ENSO events-- but these are not primary.
Briefly summarized, in El Nino, a vast region of warm seawater in the Pacific Ocean moves far to the east, to the Western United States and Pacific Coast of South America, while in La Nina it lies much further to the west, closer to Asia. This can be seen in the following images.
1997-1998 El Nino (the white and red areas indicate unusual patterns of heat storage)
Typical La Nina pattern
PDO TRUMPS ENSO
In D’Aleo’s white paper, he discusses some of the characteristics of the PDO, and its relationship to El Nino:
“First discovered in the middle 1990s (Mantua et al., 1997), the "Pacific Decadal Oscillation" (PDO) is a long-lived El Niño-like pattern of Pacific climate variability. While the two climate oscillations have similar spatial climate fingerprints, they have very different behavior in time.
Two main characteristics distinguish the PDO from ENSO: first, 20th Century PDO "events" persisted for 20-to-30 years, while typical ENSO events persisted for 6 to 18 months; second, the climatic fingerprints of the PDO are most visible in the North Pacific/North American sector, while secondary signatures exist in the tropics (the opposite is true for ENSO).
Thus, it is not surprising that the PDO predisposes the Pacific towards El Niño or La Niña. The warm PDO favors El Niño with increased frequency, strength and duration over La Niña. The cold PDO favors La Niña over El Niño with greater frequency, strength and longer duration (they are often multiyear).
A positive PDO, with its enhanced frequency of El Niños (which are wet through the winter into the spring in the South but are drier in the North), has a greater likelihood of dryness in the northern growing areas.”
So, according to D’Aleo’s assessment, the current negative phase of the PDO actually decreases the likelihood of a strong, persistent El Nino.
The phase of the PDO and its relationship to the AMO have also been linked to a greater or lesser likelihood of drought. In fact, the current relationship, in which the phase of the PDO is negative and the AMO positive, is associated with California drought, evident from USGS maps.
This linking of AMO/PDO and drought implies that a drought would not end just because of an El Nino.
In a recent presentation at JPL, it was suggested that while PDO and not El Nino is the only natural solution to the drought, perhaps a strong El Nino could “flip” the PDO? There was no reference to whether this has in fact occurred before, but to specific warming characteristics in the Pacific which might indicate this is happening-- essentially a possible early shift in the PDO which could theoretically be helped by the Pacific warming of El Nino. While there is no guarantee of this happening or certainty that this kind of causality is possible, it has also been acknowledged that the PDO can have short term oscillations, but these are distinct from its longer term cycles which have the greatest effect on weather and climate. Since the PDO has been negative since roughly 2000, a flip now would likely just be such a temporary oscillation in its more stable 50-70 year cycle.
Currently the PDO is said to be “negative” (image by Wikiuser Giorgiogp2)
Currently positive AMO (image by Wikiuser Giorgiogp2)
Based on the established cyclic character of the AMO/PDO, one would assume that the current fundamental phase of both will not change within the next decade--the PDO said to have “gone negative” around 2000 and the AMO entering into its positive phase some years before-- and according to the association of specific phases and drought prognosis, we shouldn’t count on that changing either.
LOOK TO THE SUN
There is also reason to believe that even these ocean and atmospheric cycles could be linked to the Sun. A recent study looked at how solar cycles correlated with changes in the North Atlantic Oscillation.
In an earlier paper, D’Aleo said that he thinks we will ultimately show solar cycle changes to be connected to cyclic weather phenomena like the ENSO:
“In our recent stories, we have shown how important ENSO and the multidecadal cycles in the oceans are to temperatures. It is my belief that someday we will find proof that solar changes drive the ocean cycles which drive the land temperatures.”
A reasonable, relatively near term forecast will involve an overlap of the decline in solar activity with the negative phase of both ocean cycles, and hence, cooling. As Professor Carl-Otto Weiss stated in his cited Paris presentation:
“..the recent decline of temperature is simply due to the now declining AMO/PDO. Equally the stronger temperature increase from ca. 1970 to 1995, which is always claimed to prove the warming by CO2, is simply due to the superposition of the increase of the De Vries cycle with the increase of the AMO/PDO.”
Foreseeably, both ocean cycles would be either negative (PDO) or beginning to cool (AMO) around 2020, around the same time as the Sun is in its minimum, and the 200 year De Vries cycle would further magnify a cooling effect.
CHANGE THE WATER CYCLE - DON’T WAIT ON MOTHER NATURE
The moral of this story is… don’t rely on natural cycles to solve your problems! We can intervene and change them. From large scale water infrastructure projects, to desalination and even rainmaking technologies, we can manage the global water cycle to better suit the needs of mankind. Rather than waiting on good news from your meteorologist, take action to create the needed solutions.
The solution is most emphatically NOT what California Governor Jerry Brown has suggested: to significantly decrease water use and to refer to the example of how Californians used to get along just fine with millions fewer people as some kind of model. The power of human creativity has demonstrated again and again the ability to allow for continuous growth and development-- this is, in fact, the only thing which is truly sustainable!