With just 2 months to go, it could well be that 2016 replaces 1998 as the “hottest year ever.” With the Pacific Blob only now dissipated, and La Nina delaying her appearance, it is becoming likely that the inevitable cooling will come only next year. That may result in an annual GMT surpassing 1998 in the satellite record.
Fossil fuel activists and consensus climate scientists will claim this proves CO2 is causing global warming, but knowledgeable people know they are once again dissing the Ocean in order to push their agenda.
Actual data, rather than computer models, show that ocean oscillations, not CO2 have produced the bulk of warming in the temperature record. ENSO (El Nino Southern Oscillation) produces sea surface temperature anomalies (SSTa) resulting in most of the variability in global averages.
Climatists will blame the rise on so-called “greenhouse gases” asserting several unproven notions:
- CO2 induces atmospheric warming which raises SSTs;
- Higher SSTs increase evaporation and clouds that trap LW radiation, thereby further raising surface temperatures;
- ENSO warming and cooling cycles cancel out each other leaving CO2 as the sole warming agent.
As the final results for 2016 come in, expect the media to bombard the masses with declarations along these lines. The purpose of this post is inoculation (like a flu shot) to protect against the feverish reporting ahead.
How El Nino Affects Surface Temperatures
Roy Spencer and William Braswell looked at the data in their 2014 published article (here)
The Role of ENSO in Global Ocean Temperature Changes during 1955-2011
Roy Spencer May 13, 2014 on WUWT (here):
Based on global area-average ocean signatures, the observational evidence regarding the *global oceanic* signature of El Nino is this:
1) El Nino involves a decrease in the overturning in the 0-200 m layer, which leads to warming of the upper 100 m and cooling of the 100-200m layer. We calculate this is 2/3 of the source of surface warming.
2)El Nino surface warmth is partly driven by a decrease in cloud cover letting more sunlight in…This is 1/3 of the surface warming, and it also appears to contribute to longer-term deep ocean warming if there are stronger El Ninos and weaker La Ninas than average..
In the same thread Bob Tisdale comments:
ENSO impacts when and where sunlight reaches the surface of the oceans and penetrates into the oceans. . . ENSO also impacts how energy is released from the oceans to the atmosphere which further impacts the energy balance.
Keep in mind that the majority (about 90%) of the heat released from the ocean is through evaporation. During an El Nino, more of the surface of the tropical Pacific is covered with warm water, which yields more evaporation. And the opposite holds true during a La Nina.
Ocean Heat Also Rises
When there are super-El Nino years such as 1998 and 2016, climatists insist on attributing warming to fossil fuel emissions. Obsessed with CO2 and radiative energy flows, they are unable to see and affirm this oceanic climate driver. An extended discussion at Climate Etc. (here) included a series of comments by Kristian that provide a synopsis of El Nino’s role in global warming.
This is what the data consistently shows: surface temps up (or down) > tropospheric temps up (or down) > OLR at ToA up (or down).
This is how the heat from the sun actually flows through the earth system. Surface warms first, then the troposphere, then, as a consequence of this, the radiative output to space increases. There is NO observational evidence anywhere for the opposite process to occur: OLR at ToA down >tropospheric temps up > surface temps up.
Radiatively active gases in the atmosphere do not enable it to WARM. It would’ve warmed with or without them, simply by being directly convectively coupled with the solar-heated surface. This connection is never broken as long as there is air present, a gravity field and sunshine heating the surface.
Radiatively active gases, however, DO enable the atmosphere to adequately COOL to space. Because this can only be done through radiation.
So an atmosphere without radiatively active gases would still WARM from the surface up, but wouldn’t be able to adequately COOL to space.
It’s not the so-called ‘GHGs’ that trap the surface heat. It’s the 99.5% of the atmosphere NOT being significantly radiatively active at ‘earthly’ temperatures that would do that. Because this part can STILL be warmed conductively, convectively and latently, but it can’t to any real extent radiate it away again.
ENSO Discharges and Recharges Ocean Heat Content
As a rule of thumb, El Niños cause global warming but drain global heat (actually, ‘energy’) content. El Niño: global surface/troposphere temps UP, global internal energy DOWN.
Why the distinction? Because most of the stored-up (solar) energy of the earth system is to be found at depth in the oceans, that is, AWAY FROM the surface. What an El Niño does is to pull a significant amount of this energy up from its hiding place in the deep and instead spreads it out across a huge area on the surface, raising its temperature in the process, laying the energy bare, so to speak, to be lost from the ocean to the atmosphere (and ultimately to space) through evaporation (deep/moist convection) and conduction. Radiation also occurs but to a much lesser degree.
So, the depths of the ocean – well, basically of the IPWP (the Indo-Pacific Warm Pool) – is drained of energy during an El Niño, it ‘cools’, while the surface in the tropics of the Central and East Pacific (where the NINO3.4 region is located), warms up immensely, the SST here shoots up.
Following this significant tropical Central and East Pacific surface warming, the troposphere above it warms from the vastly increased transfer and freeing of latent heat. The warming of the tropical Pacific also affects the atmospheric circulation over the rest of the tropics through so-called ‘atmospheric bridges’, indirectly inducing a lagged warming also in the Atlantic and Indian ocean basins.
From the tropics/subtropics, part of the El Niño released ocean heat is then transported (mostly via the atmosphere) out to the extratropics, eventually ending up in the polar regions (well, in reality it mostly ends up in the Arctic, not in the Antarctic, the reason being a profound difference between northern and southern hemisphere extratropical circulation.)
The massive amount of energy released onto the world during an El Niño event is neither generated by nor absorbed during the event itself. The energy of course originally came from the sun and it was stored up during the La Niña normally preceding the El Niño.
It’s the La Niñas (and often also during neutral ENSO conditions, much more resembling the cool events than the warm events) that builds ‘global heat content’. They soak up the solar energy and store it at depth. The El Niños subsequently release it again.
Global Warming Since 1970 Due to Major El Ninos
Since 1970 we have seen four ENSO sequences where a strong and solitary El Niño is surrounded by (preceded AND succeeded by) La Niña-events. In each sequence, the storing up of energy during the often extended/prolonged La Niña periods has far outdone the energy depletion during the strong, but mostly short El Niño-events.
1. During the period 1970-76 only one year saw an El Niño (1972/73). The rest of the years, 1970-72 and 1973-76, were mostly La Niña-dominated.
2. During the period 1983-89, two years back-to-back saw El Niño-conditions (1986-88). The years 1983-86 saw either cold neutral or La Niña-conditions and the year 1988/89 saw one of the strongest La Niñas of modern history.
3. During the period 1995-2001 only one year saw an El Niño (1997/98). The rest of the years, 1995-97 and 1998-2001, were mostly La Niña-dominated.
4. During the period 2007-14 only one year saw an El Niño (2009/10). The rest of the years, 2007-09 and 2010-14, were mostly La Niña-dominated.
5. Beginning in 2015 another major El Nino event occurred, peaking mid 2016. From past experience, we expect a La Nina to follow in coming months. Over the next few years it will be evident whether or not a new step level results from this event.
The periods in between these sequences of clustered distinct cool and warm ENSO events, 1976-83, 1989-95 and 2001-07, were all neutral to warmish, with much smaller variations from the mean state and prominently without any clear extended cold events, lacking the strength to create a global signal.
El Nino temperatures correlate well with satellite global temperatures
The oceans are not some passive reservoir where the solar energy just comes and goes as it wants and always in complete balance. No, they are quite dynamic and the absorbed energy is held back or is released, according to their own internal processes. If the climatic conditions (the coupled ocean/atmosphere system) in the Pacific basin are such that they promote net storage of solar energy over several decades, well, then that is what will happen. Quite naturally. That doesn’t mean that these conditions will prevail forever.
We KNOW that large-scale and fairly abrupt climate shifts occur in the (pan-)Pacific basin at certain intervals. In fact, there has been no additional global warming OUTSIDE of these sudden hikes, from 1970 till today. That means, the ENTIRE modern global warming seen since 1970 is contained within the steps up during the Great Pacific Climate Shift of the late 70s and the two following ones in 1988/89 and 1998/99.
The ENTIRE modern global warming is found in these three sudden hikes alone, all occurring within the time-span of less than a year.
El Nino Spreads Warming From Sea to Sea
How did global warming progress from 1975/76 to 2001/02? Follow the data. No preconceived ideas about mechanisms.
First of all, there is no question that there is a definite East Pacific signal plastered all over the global temperature series. Compare with NINO3.4:
In fact, global temperatures tend to lag NINO3.4 SSTa by several months. And everyone knows that this particular correlation also speaks causation. Not just from the consistent and tight lead-lag relation, but from the thoroughly explicated oceanic/atmospheric mechanisms by which we know the large-scale and integrated ENSO process creates global warming and cooling. I’m talking here about the major swings up and down that we see all along from 1970 till today.
What went on in 1978/79, in 1988 and in 1998? What was so special about these three short time segments? Why is the ENTIRE ‘modern global warming’ contained within them?
Those upward shifts are the long-term responses to the discharge phases of ENSO that occurs during strong El Niños. As part of the discharge phase of ENSO, the El Niño takes warm water from below the surface of the western tropical Pacific and places it on the surface (warm water that was created by the increased sunlight during the prior recharging La Niña). The discharged warm water floods into the East Pacific, where it temporarily raises sea surface temperatures during the El Niño, but causes little long-term trend there.
And at the end of the El Niño, the warm water is redistributed by the renewed trade winds, ocean currents and the downwelling Rossby wave into the West Pacific, Indian Ocean and eventually the South Atlantic. The East Pacific represents about 33% of the surface of the global oceans, and the South Atlantic-Indian-West Pacific covers another 52%. That leaves the North Atlantic, which has another mode of natural variability called the Atlantic Multidecadal Oscillation. The Atlantic Multidecadal Oscillation, according to NOAA, can contribute to or suppress global warming. And so far, the only global surface warming we’ve seen was in the South Atlantic-Indian-West Pacific subset and that warming was caused by discharge of sunlight-created warm water released from below the surface of the West Pacific Warm Pool during El Niño events.
For data on ocean-air heat exchanges see: Empirical Evidence: Oceans Make Climate