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Eric Holthaus: Latest NMME shows all-in on La Niña. Most certainty I've seen so far, despite current low-predictability window.
https://twitter.com/ericholthaus/status ... 5310868480

The last time the Earth had an El Nino event like 2015/16 was in 1997/98[1]. The two events are actually very much alike, peaking at about the same time in the first year and at about the same temperature in the Nino 3.4 section of the equatorial Pacific. In the 1997/98 case the jump in temperatures and year-on-year increases in atmospheric carbon dioxide lasted through the summer of the second year, with the first few months of the year being extra-hot. We seem to be setting up for the same thing in 2016, as January, February and March have already set new records, with both February (1.64°C)[2] [3] and March (1.58 °C)[4] [5] breaching the internationally agreed “safe-zone” of 1.5 °C above pre-industrial times set in Paris last year. The year-on-year increases in atmospheric carbon dioxide have also ramped up, with February showing a 3.4ppm increase, and recent readings at Manua Loa being well above 4ppm year over year[6].

So 2016 could provide a scorching Northern Hemisphere summer, and another record jump in global average temperatures and atmospheric carbon dioxide levels. The big question is whether or not the Earth system is being pushed to the point where the natural sources of carbon emissions (e.g. permafrost melting, peat bog and forest fires) will significantly increase and/or carbon sinks (e.g. ocean uptake of carbon dioxide, forested areas) will degrade. If the differences between 2016 and 2015 are bigger than the differences between 1998 and 1997, then there may be a cause for concern. For the Jan-March period the difference is significant at 1ppm, a 3.32ppm year on year increase in 2016 versus a 2.29 ppm year on year increase in 1998. Another area for concern is that the temperature difference between the two El Nino events, which are separated by l8 years, is nearly 0.5°C. That’s an average of about 0.25°C per decade, which would mean that an El Nino in the 2030’s could push us straight through 2°C.

... Like a man walking toward the edge of a cliff on a foggy day who is momentarily shown a glimpse of that edge, it would be stupid to continue on the same course.

Synopsis: La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina during the fall and winter 2016-17.

During the past month, sea surface temperature (SST) anomalies decreased across the equatorial Pacific Ocean, with near-to-below average SSTs recently emerging in the eastern Pacific (Fig. 1). The latest Niño region indices also reflect this decline, with the steepest decreases occurring in the Niño-3 and Niño-1+2 regions (Fig. 2). The surface cooling was largely driven by the expansion of below-average subsurface temperatures, which extended to the surface in the eastern Pacific (Figs. 3 and 4). While oceanic anomalies are clearly trending toward ENSO-neutral, many atmospheric anomalies were still consistent with El Niño, such as the negative equatorial and traditional Southern Oscillation indices. Upper-level easterly winds persisted over the central and eastern Pacific, while low-level winds were near average. Enhanced convection continued over the central tropical Pacific and was suppressed north of Indonesia (Fig. 5). Collectively, these anomalies reflect a weakening El Niño and a trend toward ENSO-neutral conditons.

Most models predict the end of El Niño and a brief period of ENSO-neutral by early Northern Hemisphere summer (Fig. 6). The model consensus then calls for increasingly negative SST anomalies in the Niño 3.4 region as the summer and fall progress. However, there is clear uncertainty over the timing and intensity of a potential La Niña (3-month Niño-3.4 SST less than or equal to -0.5°C). The forecaster consensus favors La Niña onset during the summer, mainly weighting the dynamical models (such as NCEP CFSv2) and observed trends toward cooler-than-average conditions. Overall, La Niña is favored to develop during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina during the fall and winter 2016-17 (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period).

This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA's National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPC's Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 9 June 2016. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: [email protected].

dohboi wrote:Another area for concern is that the temperature difference between the two El Nino events, which are separated by l8 years, is nearly 0.5°C. That’s an average of about 0.25°C per decade, which would mean that an El Nino in the 2030’s could push us straight through 2°C.

dohboi wrote:El Niño is over, but leaves nearly 100 million short of food

http://gu.com/p/4jtnz/stw

Interesting that we have one of the most powerful El Nino's in history but the follow on La Nina has failed to appear.

onlooker wrote:Is it possible that we have crossed a threshold whereby La Nina will no longer appear?

Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño-like conditions with impacts similar to those of the 1997/1998 El Niño event. Here we use a general circulation model to examine the global-scale effects that result from imposing warm tropical sea surface temperature (SST) anomalies in both modern and Pliocene simulations. Observed SSTs from the 1997/1998 El Niño event were used for the anomalies, and incorporate Pacific warming as well as a prominent Indian Ocean Dipole event. Both the permanent El Niño (also called El Padre) and Indian Ocean Dipole (IOD) conditions are necessary to reproduce temperature and precipitation patterns consistent with the global distribution of Pliocene proxy data. These patterns may result from the poleward propagation of planetary waves from the strong convection centers associated with the El Niño and IOD.

Abstract
The El Niño/Southern Oscillation (ENSO) system during the Pliocene warm period (PWP; 3-5 million years ago) may have existed in a permanent El Niño state with a sharply reduced zonal sea surface temperature (SST) gradient in the equatorial Pacific Ocean. This suggests that during the PWP, when global mean temperatures and atmospheric carbon dioxide concentrations were similar to those projected for near-term climate change, ENSO variability--and related global climate teleconnections-could have been radically different from that today. Yet, owing to a lack of observational evidence on seasonal and interannual SST variability from crucial low-latitude sites, this fundamental climate characteristic of the PWP remains controversial. Here we show that permanent El Niño conditions did not exist during the PWP. Our spectral analysis of the δ(18)O SST and salinity proxy, extracted from two 35-year, monthly resolved PWP Porites corals in the Philippines, reveals variability that is similar to present ENSO variation. Although our fossil corals cannot be directly compared with modern ENSO records, two lines of evidence suggest that Philippine corals are appropriate ENSO proxies. First, δ(18)O anomalies from a nearby live Porites coral are correlated with modern records of ENSO variability. Second, negative-δ(18)O events in the fossil corals closely resemble the decreases in δ(18)O seen in the live coral during El Niño events. Prior research advocating a permanent El Niño state may have been limited by the coarse resolution of many SST proxies, whereas our coral-based analysis identifies climate variability at the temporal scale required to resolve ENSO structure firmly.

Summary
In summary, our simulations, together with earlier modeling and reconstruction studies, indicate that ENSO existed in the mid-Pliocene warm climate. However, it remains difficult to determine the intensity of ENSO variability because of the model-model discrepancies and the lack of geological evidence. It remains important to investigate which change of the ENSO mode, weaker or non-weaker, is more reasonable in terms of modeling, but obtaining data to show the standard deviations of the mid-Pliocene interannual SST in the tropical Pacific will be a challenge.