From AGU EOS —Terri Cook, Freelance Writer
Was the Recent Slowdown in Surface Warming Predictable?
From the early 2000s to the early 2010s, there was a temporary slowdown in the large-scale warming of Earth’s surface. Recent studies have ascribed this slowing to both internal sources of climatic variability—such as cool La Niña conditions and stronger trade winds in the Pacific—and external influences, including the cooling effects of volcanic and human-made particulates in the atmosphere.
Several studies have suggested that climate models could have predicted this slowdown and the subsequent recovery several years ahead of time—implying that the models can accurately account for mechanisms that regulate decadal and interdecadal variability in the planet’s temperature. To test this hypothesis, Mann et al. combined estimates of the Northern Hemisphere’s internal climate variability with hindcasting, a statistical method that uses data from past events to compare modeling projections with the already observed outcomes.
The team’s analyses indicate that statistical methods could not have forecast the recent deceleration in surface warming because they can’t accurately predict the internal variability in the North Pacific Ocean, which played a crucial role in the slowdown. In contrast, a multidecadal signal in the North Atlantic does appear to have been predictable. According to their results, however, its much smaller signal means it will have little influence on Northern Hemisphere temperatures over the next 1 to 2 decades.
This minor signal in the North Atlantic is consistent with previous studies that have identified a regional 50- to 70-year oscillation, which played a more important role in controlling Northern Hemisphere temperatures in the middle of the 20th century than it has so far this century. Should this oscillation reassume a dominant role in the future, argue the researchers, it will likely increase the predictability of large-scale changes in Earth’s surface temperatures.
Paper:
Predictability of the recent slowdown and subsequent recovery of large-scale surface warming using statistical methods
Authors
Michael E. Mann, Byron A. Steinman, Sonya K. Miller, Leela M. Frankcombe, Matthew H. England, Anson H. Cheung
(Geophysical Research Letters, doi:10.1002/2016GL068159, 2016)
Abstract
The temporary slowdown in large-scale surface warming during the early 2000s has been attributed to both external and internal sources of climate variability. Using semiempirical estimates of the internal low-frequency variability component in Northern Hemisphere, Atlantic, and Pacific surface temperatures in concert with statistical hindcast experiments, we investigate whether the slowdown and its recent recovery were predictable. We conclude that the internal variability of the North Pacific, which played a critical role in the slowdown, does not appear to have been predictable using statistical forecast methods. An additional minor contribution from the North Atlantic, by contrast, appears to exhibit some predictability. While our analyses focus on combining semiempirical estimates of internal climatic variability with statistical hindcast experiments, possible implications for initialized model predictions are also discussed.
Impossible to forecast? Fancy statistics don’t work well in a chaotic system with unknown unknowns but your eyeball will give you a pretty good idea. Prof Akasofu did so in his paper back in 2008. See Fig 2b
http://people.iarc.uaf.edu/~sakasofu/pdf/two_natural_components_recent_climate_change.pdf
I suppose we all should be grateful that Mann actually accepts now that there was a pause….
Nick Stokes May 12, 2016 at 12:46 am
“Because it was intended to be read that way by a casual reader”
Scientific papers aren’t written for casual readers. They are written for people who pay attention. But “early 2010s” is a common phrasing. And it doesn’t mean 2010.
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I see. So, after admitting that the paper doesn’t say what a casual reader of it would think it says, your position is now that it doesn’t matter because the paper wasn’t written for “those people”. The great unwashed getting the wrong impression because the paper wasn’t written for “them”? That’s now your argument? That the great unwashed have to parse every last sentence of every science paper in excruciating detail to learn if the sloppily worded summary actually matches up to the actual science?
Wouldn’t it be so much easier to just be precise in the first place?
I shall answer that question. Well yes it would. Unless of course the goal was to manipulate perception, the hallmark of marketing, not science.
Nick Stokes said: “…For the longer scale weather (ENSO) they [i.e. the models] do show the appropriate oscillations – they just can’t predict the phasing [of the long term temperature changes].
N.B. the bracketed texts are my additions.
However the Lunar tides can be used to predict the phasing of the ~ 30 year warming and cooling climate periods!
The 31/62 year Perigee-Syzygy lunar tidal cycle is produced by the synchronization of the slow precession of the lunar line-of-apse with the lunar Synodic cycle (i.e the Moon’s phases) and the Earth’s seasons.
A detailed investigation of the precise alignments between the lunar synodic [lunar phase] cycle and the 31/62 year Perigee-Syzygy cycle over the period between 1865 and 2025 shows that they naturally breaks up six 31 year New Moon and Full Moon tidal epochs.
N.B. The New Moon tidal epochs have peak seasonal tides that are dominated by new moons that are predominately in the northern hemisphere, while the Full Moon epochs have peak seasonal tides that are dominated by new moons that are predominately in the northern hemisphere.
The six tidal epochs of the 31/62 year Perigee-Syzygy lunar tidal cycles between 1865 and 2025.
Epoch 1 – Prior to 15th April 1870 ___________________New Moon Epoch
Epoch 2 – 15th April 1870 to 18th April 1901____________Full Moon Epoch
Epoch 3 – 8th April 1901 to 20th April 1932_____________New Moon Epoch
Epoch 4 – 20th April 1932 to 23rd April 1963____________Full Moon Epoch
Epoch 5 – 23rd April 1963 to 25th April 1994____________New Moon Epoch
Epoch 6 – 25th April 1994 to 27th April 2025____________Full Moon Epoch
If you look at figure 5 of Bob Tisdale’s post at:
https://bobtisdale.wordpress.com/2016/05/12/does-ed-hawkinss-spirally-global-temperature-animation-defeat-its-purpose/
that shows the world mean temperature times series, you find that there are five noticeable increases or decreases in the World’s mean temperature between 1865 and 2015, with all except the last one spanning a period of ~ 30 year.
Period__________World mean temperatures
1880 – 1912___________ Cooling
1912 – 1943 ___________Warming
1943 – 1975___________Cooling
1975 – 2005___________Warming
2005 – 2015___________Cooling (= first 10 years of 30 year epoch?)
What is remarkable is that the transitions between a cooling and warming in the World’s mean temperatures almost precisely match up with dates that are 10 years after the transitions of the 31/62 Perigee-Syzygy tidal cycles from Full Moon to New Moon epochs.
Period________________Epoch
1880 – 1911___________Full Moon Epoch 2 + 10 years
1911 – 1942 ___________New Moon Epoch 3 + 10 years
1942 – 1973___________Full Moon Epoch 4 + 10 years
1973 – 2004___________New Moon Epoch 5 + 10 years
2004 – 2035___________Full Moon Epoch 6 + 10 years.
If this explanation is correct then the current cooling period in the World’s mean temperatures should last until about 2035.
Of course, that should have read:
“N.B. The New Moon tidal epochs have peak seasonal tides that are dominated by new moons that are predominately in the northern hemisphere, while the Full Moon epochs have peak seasonal tides that are dominated by full moons that are predominately in the southern hemisphere.”
I have a model that when two “fair dice” are rolled, the model predicts the sum of the uppermost dice faces. Unfortunately it didn’t predict that the guy in the green shirt shooting craps would make his point 10 times in a row, But it did predict he wouldn’t make his point on his eleventh pass. I’ll sell you my model for $1,000,000, Alternately, if you think my model needs improvement, you can send me $1,000,000 in grant money and I’ll give you the model after I have improved it.
And based on the GCM climate models we’re supposed to drastically change the way produce useful energy while simultaneously funding improvements to the climate models. With equal correctness, such action can be called Voodoo Science or Voodoo Economics–take your pick.
Hmmm….so the models couldn’t get the last 20 or years right but we can trust them enough to act on their output?
I wonder if he’s positioning himself to be perceived as more “trustworthy” than he has been?
“Well, yes, there was a pause…but just wait till this summer!”
Mann’s attitude towards models in this paper can best be stated as — Caesar is ass but all hail Caesar!
Eugene WR Gallun
But… but… but… they told us the AGW was unstoppable. All those tipping points, all those 5 or 10 year predictions if we didn’t stop CO2 NOW…
Did they lie to us all?
For MONEY?
MarkMcD — You cynic, you. Believing the worst about those people! — Eugene WR Gallun
Surely perusal of the graphs showing the global temperature history from 1880 should have provided a strong hint that another pause in temperature rise might well occur around the year 2000. That it did occur (beginning in 2002 the way I interpret the graphs) should give credence to the presence of a pattern of temperature change that appears to be predictable. Any conclusion that the pause has ended appears to be premature. Events like El Nino are distractions from the underlying pattern of temperature change and should be ignored for purposes of accurately evaluating that apparent pattern.