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Friday, October 10, 2014

The Pacific Decadal Oscillation and Australia - plus more

Sou | 10:43 PM Go to the first of 68 comments. Add a comment

Here is the article about the Pacific Decadal Oscillation, with particular reference to Australia. I'll warn you in advance - it's long, a bit meandering, probably could do with more illustrations, and not a complete guide to everything. That's my excuses out of the way. I figure I've spent enough time on it so here it is. Feel free to add what you know and correct what I don't :)

In the previous article, I referred to some comments by a contributor, trying to argue that Australia's record heat of the 2012-13 summer was caused by a (non-existent) spike in the PDO index, or was an advance reaction to a spike that had not yet appeared. His comments were not easy to follow. Thing is, the PDO index wasn't positive during the Australian summer of 2012-13. In fact it did not register as positive until January 2014. There's more to it than that, in any case.

This is some of what Rum Runner wrote:
October 8, 2014 at 5:48 PM
How much of the temperature spike in 2013 was due to the spike in the PDO at that time? In fact Australian temperatures in general broadly follow the PDO (not surprisingly).
Plot:
http://oi59.tinypic.com/29p25u0.jpg
From data:
http://www.bom.gov.au/web01/ncc/www/cli_chg/timeseries/tmax/0112/aus/latest.txt
http://www.woodfortrees.org/data/jisao-pdo/from:1910

Here is Rum Runner's chart (as always, click the chart to enlarge it):

Chart 1: from Rum Runner


Here is another chart of the same thing, with an average annual PDO index plotted against the average annual temperature anomaly from 1961-1990 for Australia. The PDO index can be positive or negative. When positive it's referred to as being in a warm phase. When negative it's referred to as being in a cool phase.

Chart 2: Data sources: BoM and Nate Mantua


In Chart 2 above, the PDO index is the shaded bit coloured tan and the temperature anomaly is the blue line. I've also marked the different PDO phases as recognised in the literature as far as I can tell. (The period since the late 1990s is a bit of an odd one. It has a dip in the index, followed by a rise, followed by another dip. It's also behaved a bit differently to prior periods, which I'll touch on later.) Chart 2 also shows more clearly the fact that the temperature (the green line in Chart 1 and the blue line in Chart 2) is quite a bit lower in the first half of last century. Temperatures are going up as greenhouse gases warm the earth more. As you can see, the annual mean temperature for Australia as a whole has been going up and is considerably higher in the second half of the twentieth century, particularly so the past few years, with 2013 being the hottest year on record by a long shot.

In Chart 3 below, I've selected a shorter timeline so you can see what's happened recently more clearly.

Chart 3: Data sources: BoM and Nate Mantua

As you can see in Chart 3, there was no "spike" in the PDO index over the summer 2012-13 or the period leading up to it. The values from September 2012 through to February 2013 were all negative as follows:  -2.21;  -0.79;  -0.59;  -0.48;  -0.13;  -0.43. During the record hot year 2013, the PDO index stayed negative all year, even dropping as low as -1.25 in July 2013.

If you look closely at the period from 1980 onwards (Chart 3 above), you can see that the annual mean temperature of Australia dropped in the early 1980s while the PDO was in its warm phase. It jumped up in 1990 when the PDO dipped briefly to negative. in the late 1990s it was a tad out of phase with the PDO index but then in the early 2000s it appeared to be more in phase briefly. Then when the PDO went negative again around 2007, the temperatures remained high. It wasn't until the massive La Ninas of 2010-11 that the temperature dropped again. And despite the PDO being in a cool phase in 2012-13 (and in the absence of an El Nino), 2013 was Australia's hottest year on record.

In other words, on face value, there doesn't appear to be a strong relationship between the PDO and temperatures averaged across all Australia. If you were to rely on eyeballing the chart, you'd probably conclude that any period where the PDO aligns more or less with a change in surface temperature in Australia looks to be mere coincidence. But it would be wrong to conclude that there is no known association between the PDO and Australian weather.

The phases of the PDO and the related IPO do coincide with patterns of weather in Australia. Thing is, different parts of Australia behave differently during the two phases. But before discussing that, I'll just say a little bit about the PDO itself.


About the Pacific Decadal Oscillation


The name "Pacific Decadal Oscillation" was coined by Stephen Hare in his PhD dissertation of 1996, "Low Frequency Climate Variability and Salmon Production" (no link). Dr Hare is a fisheries biologist, now working at the Secretariat of the Pacific Community advising on scientific issues related to management of tuna stocks. Back in 1997, as part of his PhD research, he co-authored, with Nate Mantua and others, what has become the second most cited paper in fisheries history. (According to Google Scholar it has been cited 4,342 times, which is very impressive. I believe this paper, "Stages of embryonic development of the zebrafish", is the most cited fisheries paper, cited 5077 times according to Google Scholar.)

The 1997 Mantua/Hare et al paper is one many of you may be familiar with or heard of: "A Pacific interdecadal climate oscillation with impacts on salmon production." Nate Mantua and Stephen Hare later wrote another paper in 2001, simply called "The Pacific Decadal Oscillation". This oceanic phenomenon has been studied quite a lot, and continues to be a subject of active research.

Nate Mantua describes the PDO as follows:
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. 

He has developed a PDO index, described as:
"the leading PC [Principal Component] of monthly SST anomalies in the North Pacific Ocean, poleward of 20N. The monthly mean global average SST anomalies are removed to separate this pattern of variability from any "global warming" signal that may be present in the data." 

There is a bit more information on this provided in Mantua and Hare (2001), where they write:
A PDO index developed by Hare (1996) and Zhang (1996), also used by Mantua et al. (1997), is the leading PC from an un-rotated EOF analysis of monthly, “residual” North Pacific sea surface temperature (SST) anomalies, poleward of 20°N for the 1900–1993 period of record (see lower panel of Fig. 1). “Residuals” are here defined as the difference between observed anomalies and the monthly mean global average SST anomaly (see Zhang et al., 1997).

They continue by describing the persistence of the sign of the index on the decadal scale:
A remarkable characteristic of this index is its tendency for multiyear and multidecadal persistence, with a few instances of abrupt sign changes. Based on a variety of studies, sign changes beginning in 1925, 1947, and 1977 have been labeled regime shifts (Hare and Francis, 1995; Zhang et al., 1997; Mantua et al., 1997; Minobe, 1997).

Warm and cool phases of the PDO


As described on the NOAA website, the PDO shifts between a positive phase (warm) phase and a negative (cool) phase. The PDO has a positive value (warm phase) when sea surface temperatures (SSTs) are anomalously cool in the interior North Pacific, while the Pacific Coast (of North America) is anomalously warm. And when the opposite happens, a cool anomaly along the Pacific Coast and anomalously warm interior North Pacific, then it's known as a cool phase and the index is negative. In the warm phase, the sea level pressures are below average over the North Pacific. In the cool phase the sea level pressures over the North Pacific are above average.

Nate Mantua provides a diagram illustrating the difference between a typical warm phase and a typical cool phase in the northern hemisphere winter:

Typical wintertime Sea Surface Temperature (colors),
 Sea Level Pressure (contours) and surface windstress (arrows) anomaly patterns during warm and cool phases of PDO.
Warm phase (positive PDO index) is on the left and the cool phase (negative PDO index) is to the right.
Source: Nate Mantua

The PDO vs ENSO


Mantua and Hare (2001) describes three characteristics that distinguish the PDO from the El Nino Southern Oscillation (ENSO) (my dot points):
  • first, 20th century PDO events persisted for 20–30 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, while the opposite is true for ENSO; and 
  • third, the mechanisms that cause PDO are not currently known, while causes for ENSO are relatively well understood (Mantua et al., 1997; Zhang et al., 1997).

Since 2001 there has been a lot of research exploring the PDO, and others have developed different ways of measuring it as well. Kevin Trenberth and John Fasullo, in their 2013 paper, "An apparent Hiatus in Global Warming", wrote: "While the ENSO interannual variations are reasonably well known, the decadal variations are not." They were referring to the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) and associated Interdecadal Pacific Oscillation (IPO). This isn't surprising because the phases last for a long time. Reliable observations only go back so far, and sea surface temperatures are probably more iffy than land surface ones would be over the past century or so.


Is the PDO changing?


I came across an abstract from AGU13 Fall Meeting, by Stephanie McAfee, which suggested that the PDO these days isn't the same as it was earlier last century (extract, my paras):
...There are a number of critical differences in the climatic expression of the negative PDO of similar magnitude before and after 1976. In comparison to negative PDO winters between 1949 and 1976, recent negative PDO winters were associated with warmer SSTs in the north Pacific, a stronger Aleutian Low, more pronounced ridging at 500 hPa over western Canada, substantially higher temperatures over Alaska and western Canada, and wetter conditions over the central United States.
The difference in climate conditions associated with negative PDO indices between the mid-20th century and early 21st century suggests that either equivalent PDO index values may be derived from distinct climate forcings or that the PDO's teleconnections may not be temporally stable. ...

She's since published a paper that looks to be an expansion of this same topic, though I've only seen the abstract.


Seasonality of the PDO and leading ENSO


There are a few other things worth noting about the PDO before I move onto talking about Australia. Several papers discuss the seasonality of the PDO. For example, Newman et al (2003) write about comparing two years while the PDO is in a particular phase. It is mostly highly correlated with itself (two years later) in the northern hemisphere late winter/early spring and there's near zero correlation in November.

Further, there is reported to be a strong relationship between ENSO and the PDO (which isn't surprising). Matthew Newman et al (2003) described this as (my emphasis):
It has been suggested that decadal variability in the North Pacific may be more prominent during summer than during winter (e.g., Zhang et al. 1998). Our results suggest just the opposite: the PDO has little multiyear persistence during summer, so decadal variability of North Pacific SST is largely a winter/spring phenomenon. The confusion occurs because there is some correlation of the PDO between consecutive summers, but this is likely a consequence of the annual cycle of ENSO and the strong ENSO–PDO relationship that exists in both summer and winter (Fig. 1d); that is, a growing ENSO forces the PDO in summer, the subsequent mature phase of ENSO forces the PDO the following winter/spring, and this North Pacific SST anomaly then persists into the early part of the following summer.

The atmospheric bridge


That study also suggested that more of the decadal variability is reflected in the sea surface temperature rather than in the atmosphere. "Consistent with earlier studies, the NPI [North Pacific index] results suggest that the atmospheric component of North Pacific decadal variability is weaker than the SST component."

Kevin Trenberth and James Hurrell developed the North Pacific index as defined in their paper from 1994. As they wrote:
It has often been stated that the atmosphere has a very short memory while the ocean has enormous thermal inertia so that it is the ocean that provides the important memory for climate variations. In fact, however, it is the collaborative interaction between the atmosphere and the ocean and other parts of the climate system that gives rise to the important climate variations.

The NPI is described on the NCAR UCAR website as:
The North Pacific Index (NP index or NPI) is the area-weighted sea level pressure over the region 30°N-65°N, 160°E-140°W. The NP index is defined to measure interannual to decadal variations in the atmospheric circulation. The dominant atmosphere-ocean relation in the North Pacific is one where atmospheric changes lead changes in sea surface temperatures by one to two months. However, strong ties exist with events in the tropical Pacific, with changes in tropical Pacific SSTs leading SSTs in the north Pacific by three months.

The NPI is a measure of how strong the Aleutian low is during the northern winter, and "encompasses the area of maximum sea level pressure variance in the North Pacific for all months". I won't be getting into a discussion of the Aleutian low or any part of the atmospheric/ocean interaction in this article. Not because it's not important, it is central to any in-depth understanding of PDO/ENSO science. It's because I want to move on to the PDO and Australia. And, yeah, it would probably take another few days to come to grips with the subject matter. It's discussed a bit in the Wikipedia article on the PDO, with references to give you a head start.)

If you want to read more about teleconnections, the atmospheric bridge, or how ENSO affects the North Pacific, north tropical Atlantic, and Indian Oceans, in addition to the 1994 paper by Trenberth and Hurrell, there is a highly-cited 2002 paper by Alexander et al. Plus there's always Google Scholar for more recent work.


The PDO connection with temperature and precipitation in Australia


Now one of the reasons I'm writing this is to see how the PDO affects Australia. The paper by Mantua and Hare (2001) mentions Australia a few times, starting with the abstract:
A growing body of evidence highlights a strong tendency for PDO impacts in the Southern Hemisphere, with important surface climate anomalies over the mid-latitude South Pacific Ocean, Australia and South America.

Australia is big. Different parts of the country have different climates. Mantua and Hare suggest that the warm phase of the PDO coincides with anomalously warm-dry conditions in eastern Australia and anomalously wet periods in western Australia.

The cool phase of the PDO is associated with anomalously cool-wet conditions in eastern Australia. They also state that for the November to April period (the wet season in northern Australia), warm phases of the PDO coincide with anomalously warm temperatures in northwestern Australia.


Precipitation in eastern Australia

A lot of the papers relating to the PDO (or the related IPO) in regard to its impact on Australia, were about precipitation more than temperature. I came across a 2009 paper in GRL by Hamish McGowan and colleagues, which found that for more than 500 years, the PDO index (of Shen et al 2006) is highly correlated to inflows to the headwaters of the Murray-Darling system. The Darling is Australia's longest river and it flows into the Murray, which is Australia's largest river. Both are in eastern Australia. The headwaters of the Murray itself are not far north of where I live and the mouth of the Murray in South Australia. At the time of writing their paper, south eastern Australia was in arguably in it's worst drought on record (the Big Dry). Going by this paper, it was the worst drought in 529 years at least. McGowan et al wrote in the abstract:
Here we show that the >500 year PDO index of Shen et al. (2006) is highly correlated with inflows to the headwaters of Australia's longest river system, the Murray-Darling. We then use the PDO to reconstruct annual inflows to the Murray River back to A.D. 1474. These show penta-decadal and quasi-centennial cycles of low inflows and a possible 500 year cycle of much greater inflow variability. Superimposed on this is the likely influence of recent anthropogenic global warming. We believe this may explain the exceptionally low inflows of the past decade, the lowest of the previous 529 years.

They were talking about penta-decadal and quasi-centennial cycles. The second chart at the top of this article shows the period since the late 1990s as being a cool phase of the PDO, which would suggest that eastern Australia should have been wetter. (Cool phase = cooler wetter in the east; warm = warmer, dry in the east.) Well, there were arguably Australia's biggest floods on record - across the nation as a whole, in 2010-11, but you'll notice that the PDO index is positive for a short period from August 2002 to August 2007, dropping back into negative territory a few times in that period. Maybe it will take some time before it is decided exactly when the "cool" phase started and stopped. (Or maybe the PDO itself is changing with global warming.) In any case, this research would have been done six years ago, in 2008 or beforehand (it was submitted in December 2008). Therefore there would have been no clear signal of exactly when/if the PDO changed from the warm phase to the cool. The authors write (my emphasis):
Many historical hydrometeorological records document regime changes in the PDO in the mid-1940s (warm to cool) and mid-1970s (cool to warm). Interpretation of recent satellite images suggests that another change is in progress (warm to cool). Instrument records therefore only record three regime changes. This is inadequate to capture longer term variability in the PDO such as change in amplitude and/or periodicity. This information is required to improve understanding of the causes and magnitude of natural variability in regional hydroclimatology, particularly at inter-decadal time scales. In Australia, the most developed arid continent, this information is critical to the design of informed medium to long term water resource management policy.
I won't go into everything discussed in that paper. Figure 3 shows what they found in regard to the PDO and inflows to the Murray-Darling. I've added my own annotations to their Figure 3, to colour the modeled inflows blue so it stands out more, and shade the periods where the PDO index was negative. You can see that the inflows (blue line) are much higher when the PDO index is sharply negative and drop off in the warm phase of the PDO. It's not a perfect mirror image but it's close. Click the image to enlarge it.:

Figure 3: Inflows to the headwater catchments of the Murray River from A.D. 1474–1994 modelled using the Shen et al. [2006] PDO. 
Adapted from McGowan 2009.
Their research suggests that the in the warm phase of the PDO, the inflows dry up and in the cool phase the inflows increase, although it doesn't look quite as simple as that. However the scientists themselves didn't just eyeball the chart. they did statistical analysis. The conclusion of that paper is that the PDO is a "robust indicator of the hydroclimatology of the headwaters of the Murray River". They add that:
Interestingly, inflows during the past decade are far less than the lowest of the modeled inflow record for the previous 529 years. Whether this reflects a global warming signal on the hydroclimatology of southeastern Australia is unknown. However, it highlights the urgent need for future studies to reconstruct inflows to rivers of critical national importance such as the Murray River, preferably using a locally derived PDO index which is likely to better reflect local conditions.
Anyway, that's probably enough. Most of the science suggests that PDO phases do coincide with distinct patterns of temperature and precipitation in parts of Australia. Not the same patterns all over. Eastern Australia has the opposite pattern to what is observed in the west. And the north of the country is different again. Whether any of this is "cause and effect" or whether there is another underlying mechanism, the literature is not yet clear.


ENSO, the IPO and the PDO


There is a huge amount of literature on the PDO, much more than I can hope to read let alone cover in this blog article. However there was one other interesting thing that I came across, which might be of interest. It was about how ENSO events can have a different impact on Australia, depending on the phase of the Interdecadal Pacific Oscillation (IPO). The Interdecadal Pacific Oscillation shares some characteristics with the PDO, but refers to a larger region of the oceans. The IPO, like the PDO, has ENSO-like variability on decadal and longer time scales, but the area of ocean considered extends into the South Pacific and a bit of the Indian and Atlantic. In the North Pacific, the IPO and the PDO spatial patterns are similar.

A couple of papers that kept popping up were authored by Dr Scott Power in 1998 and 1999. Power et al (1999) has been cited a lot and is still being cited fifteen years down the track. It describes different ways people have tackled a quantitative representation of the IPO. The various IPO indices are, like the PDO, based on EOF analysis of SST data. For example, Power et al (1999) states that the index derived for a larger region is similar in its evolution over time to the PDO:
Additionally, Zhang et al. (1997) showed that the temporal evolution of EOFs of SST from larger regions had an inter-decadal component which is very similar to the inter-decadal component of the EOF of extra-tropical North Pacific SST.

What Power et al (1999) found was that there is a marked difference in how ENSO events affect Australia, depending on the phase of the IPO itself. Here is the abstract (my emphasis):
The success of an ENSO-based statistical rainfall prediction scheme and the influence of ENSO on Australia are shown to vary in association with a coherent, inter-decadal oscillation in surface temperature over the Pacific Ocean. When this Inter-decadal Pacific Oscillation (IPO) raises temperatures in the tropical Pacific Ocean, there is no robust relationship between year-to-year Australian climate variations and ENSO. When the IPO lowers temperature in the same region, on the other hand, year-to-year ENSO variability is closely associated with year-to-year variability in rainfall, surface temperature, river flow and the domestic wheat crop yield. The contrast in ENSO's influence between the two phases of the IPO is quite remarkable. This highlights exciting new avenues for obtaining improved climate predictions. 

I came across more than one paper that provide evidence that in the cool phase of the IPO/PDO, La Niña events bring more and heavier rainfall to eastern Australia. This is from a more recent paper by Andrew King, Lisa Alexander and Markus Donat (2013). They write:
Our results also indicate strong interdecadal modulation of the ENSO-extreme rainfall teleconnection related to the IPO. IPO-negative phases accompany significant relationships between the strength of La Niña events and extreme rainfall in eastern Australia. In El Niño seasons, there is some indication of a similar relationship during IPO-negative years; however, further investigation is required to establish the validity of this relationship. During IPO-positive phases, these relationships break down during both El Niño and La Niña seasons. Again, this interdecadal modulation is captured in the reanalysis to some degree.
[24] The IPO plays a large role in the frequency of major flood events in eastern Australia with those during the 1950s, 1970s, and 2010–2011 all occurring while the IPO has been in its negative (more La Niña–like) phase. Very intense rainfalls in eastern Australia that lead to severe flood events are often associated with strong La Niña seasons. Given that the IPO is likely to be in its negative phase, it is possible that there will be further strong La Niña events in the coming years. Therefore, there is an increased likelihood of major flood events occurring in this region while the IPO remains in its negative phase. It is worth noting, however, that the IPO has limited predictability, and its state at any present time is unknown due to the way it is calculated. This work has shown that the states of ENSO and, to a lesser degree, the IPO provide predictability of extreme rainfall events that lead to the most devastating floods.

That second last sentence brings me back to the difficulty of knowing the current phase of the IPO at any time, but probably more so when it might be changing phases. I'd say this applies to the related PDO as well. It's not enough to have the PDO index change sign. It has to be a sustained sign change. That means waiting and deciding some time after the phase change that it was indeed a phase change. If anyone has better information about this or if I'm behind the times, let me know.


Back to the original question


If you read the previous article, about the hottest summer on record, you'll have seen that it was hot all over the continent. The PDO/IPO have different effects on different parts of the country. If the PDO is in a cool phase (remember the index was negative all during that summer), then it should have coincided with cooler, wetter conditions in eastern Australia and warmer conditions in the west. When it's in the negative, La Nina's tend to be stronger. There was no ENSO event that summer.  The wet season was delayed and the whole country heated up and stayed extremely hot for around two weeks.

I won't categorically say there was no connection with anything because weather is connected. (Not that you'd take my word for it in any case. You'd rightly ask for the scientific evidence.) The other thing is that scientists don't talk about the PDO causing this or that, or the IPO causing this or that. They discuss them in terms of coinciding with particular weather events. The PDO and IPO aren't really mechanisms. They are an observed pattern of sea surface temperature and associated atmospheric conditions that have some consistency and tend to repeat and can be measured.

There's just one more thing. The PDO index has been positive since January this year. How long it stays that way - well your guess is at least as good as mine. But think back to Rum Runner's question. He asked if a (non-existent) "spike" caused the hottest summer on record. Given a warm PDO/IPO coincides with a warmer/dryer eastern Australia, why wouldn't the summer of 2013-14 have been hotter still? It wasn't.

Now some of you probably know more than you needed to know about the PDO, IPO and Australian weather. People more knowledgeable than me will probably read this and see holes in what I've managed to glean from the literature. Please let me know in the comments if that's the case, and I'll try to fix it.

To answer Rum Runner's question - finally. I found nothing to support Rum Runner's speculation and everything to suggest he was way off beam.

You can read more about what contributed to the hottest summer on record here. It was other factors that dominated, including greenhouse warming.



Alexander, Michael A., Ileana Bladé, Matthew Newman, John R. Lanzante, Ngar-Cheung Lau, and James D. Scott. "The atmospheric bridge: The influence of ENSO teleconnections on air-sea interaction over the global oceans." Journal of Climate 15, no. 16 (2002): 2205-2231. (link to paper)

King, Andrew D., Lisa V. Alexander, and Markus G. Donat. "Asymmetry in the response of eastern Australia extreme rainfall to low‐frequency Pacific variability." Geophysical Research Letters 40, no. 10 (2013): 2271-2277. doi:10.1002/grl.50427

Mantua, Nathan J., Steven R. Hare, Yuan Zhang, John M. Wallace, and Robert C. Francis. "A Pacific interdecadal climate oscillation with impacts on salmon production." Bulletin of the American Meteorological Society 78, no. 6 (1997): 1069-1079.

Mantua, Nathan J., and Steven R. Hare. "The Pacific decadal oscillation." Journal of Oceanography 58, no. 1 (2002): 35-44. (link to paper)

Newman, Matthew, Gilbert P. Compo, and Michael A. Alexander. "ENSO-forced variability of the Pacific decadal oscillation." Journal of Climate 16, no. 23 (2003): 3853-3857. (link to paper)

Power, Scott, Faina Tseitkin, Vikram Mehta, Beth Lavery, Simon Torok, and Neil Holbrook. "Decadal climate variability in Australia during the twentieth century." International Journal of Climatology 19, no. 2 (1999): 169-184. DOI: 10.1002/joc.1627  (link to paper)

Power, Scott, Faina Tseitkin, Simon Torok, Beth Lavery, Robert Dahni, and Bryant McAvaney. "Australian temperature, Australian rainfall and the Southern Oscillation, 1910-1992: coherent variability and recent changes." Australian Meteorological Magazine 47, no. 2 (1998): 85-101. (link to paper)

Power, S., T. Casey, C. Folland, A_ Colman, and V. Mehta. "Inter-decadal modulation of the impact of ENSO on Australia." Climate Dynamics 15, no. 5 (1999): 319-324. (link to paper)

Trenberth, Kevin E., and John T. Fasullo. "An apparent hiatus in global warming?." Earth's Future 1, no. 1 (2013): 19-32. doi:10.1002/2013EF000165

Trenberth, Kevin E., and James W. Hurrell. "Decadal atmosphere-ocean variations in the Pacific." Climate Dynamics 9, no. 6 (1994): 303-319. (link to paper)

68 comments:

DJ said...

Nice work Sou, but remember RR is totally clueless about climate science. I mean, he thinks the PDO is not an index, but is actually in Celsius units. Also over at his blog he thinks that the movement of the magnetic poles is the cause of global warming. He's obviously never heard of the Laschamp event where the poles moved by several thousand kilometres with no change in temperature, totally destroying his conjecture. Nothing like a good dose of reality, but does he ever learn from his mistakes. Nooo. Of course not. Better just to attack and deride, the predictable response when someone as witless as RR can't admit to his mistakes.

I mean, if you had a financial advisor who thought the Dow Jones index was in US dollars, and you politely pointed out to them that it was an index, and he rudely and uncontrollably scoffed at you, insisting that he was right, would you let him invest your money?

numerobis said...

I might allow the idiot financial advisor to spark me to look into stock indices and what they mean, then blog my findings. That way, intelligent people could learn something. The idiot financial advisor wouldn't be the audience for my post, though they might feel targeted.

Jammy Dodger said...

"Given a warm PDO/IPO coincides with a warmer/dryer eastern Australia, why wouldn't the summer of 2013-14 have been hotter still? It wasn't."

Sou, can you explain this statement please? However I read it I am not sure what you are saying. Are you saying if there had been a spike it would have been even warmer?

Anonymous said...

Conservation of energy should not be ignored. We've all seen some skeptics try to claim that warming (and not just Australia's brutal summer, but the observed warming of the planet in general) is the result of the PDO, essentially saying that observed surface and atmospheric warming is caused by the ocean (specifically the northern Pacific) giving off energy to the atmosphere. This would require the northern Pacific to have lost energy. But all one has to do is plot ocean heat content data for the northern Pacific to see that it has clearly, undeniably gained, not lost energy. This is not to say the PDO doesn't influence surface and atmospheric temperatures (surely it does), but it should be quite obvious that it is not the cause of a century-plus warming trend.

cabc

Sou said...

I was just pointing out the fallacy of RR's position. He claimed that it was a rise in the PDO that made 2012-13 warm.

The PDO was higher in 2013-14 than it was in 2012-13 so all other things being equal, then if it was all down to the PDO, then 2013-14 summer should have been hotter than the 2012-13 summer, using RR's logic. but it wasn't.

It was just a bit of snark. The PDO was negative until January 2014 for one thing. Plus of course, opposite sides of Australia have opposite weather in the different PDO/IPO phases anyway.

Jammy Dodger said...

Ah, got it. Thanks. I was not paying enough attention to which year(s) you were referring to.

BBD said...

I'm not sure if the link will work, but if it does, this is OHC 0 - 700m N. Pacifc 1955 - 2014) (0N; 65N. 100E; -90E).

Clearly the N. Pacific is not the source of energy for a warming trend spanning at least the last 4 decades.

Rum Runner said...

Oh this is great! More fame. Two articles in a row, about one comment I made. If readers would be so kind as to cast their minds back to learning Hamlet at school, you'll recall the famous line:

"The lady doth protest too much, methinks"

Honest people - and Sou obviously isn't one, may like to actually read what I actually wrote, rather than Sou's (and other's) misinterpretations of what I wrote.

I actually said:
"How much of the temperature spike in 2013 was due to the spike in the PDO at that time?"

Note the "how much". Those of you familiar with English will note that "How much" has a range of values that stretches from some to none. I never claimed, as Sou writes that ALL of the spike in AUS temps were 100% due to the PDO. But the question of how much the PDO contributed was not mentioned in Sou's article. I thought it a question worth asking. You should too unless you want to abdicate all your critical faculties to Sou.

Sou continues lying by saying that there was no spike in PDO at that time. She's either an idiot, or a compulsive liar.

Here's the monthly data: http://www.woodfortrees.org/data/jisao-pdo/from:1910
Here's a plot of the spike: http://oi59.tinypic.com/11w8rom.jpg

That's a spike. A highly amusing, inconvenient, spike.

Note that that is the unsmoothed, un-molested, data. The data we live with month to month. Sou then gives some charts of highly smoothed, highly molested data, and says "look! they are different!" Well no shit. If it makes you feel better deceiving your readers, Sou - knock yourself out.

What I especially relish though is that my simple comment, which you decried at the time, got you worried enough that: a) you've now written two articles on it, and b) have actually done some reading which found that there IS a relationship between PDO and AUS weather! "I came across more than one paper that provide evidence that in the cool phase of the IPO/PDO, La Niña events bring more and heavier rainfall to eastern Australia."

So actual scientists are asking the question: but you didn't want the question aired here! Just amazing.

You write:

"Back to the original question

If you read the previous article, about the hottest summer on record, you'll have seen that it was hot all over the continent. The PDO/IPO have different effects on different parts of the country. If the PDO is in a cool phase (remember the index was negative all during that summer), then it should have coincided with cooler, wetter conditions in eastern Australia and warmer conditions in the west."

The index was NOT negative all summer! Look at the data! You are in denial. :-D

Look down Sou. You see that big solid thing? That's the earth. Come down and join us anytime.

Rum Runner said...

Now, it seems I have another stalker! I am rather gorgeous, so I can understand your obsession, but please, I don't want to find you rooting through my dustbins. That would be creepy.

@George Montgomery

He starts with the (for this blog) usual lies:
Said I claimed: "the record heat in Australia 2012-13 couldn't be attributed to global warming". Read what I actually wrote George. Don't trust the voices in your head. Not all of them are right.

He then digs up a graph I posted, and am rather fond of, of the relationship between the AMO (Sou, that's different to the PDO in case you were wondering) and global temperatures (Sou, global means everywhere in the world - including Australia). It's a great plot. Here it is:

http://www.woodfortrees.org/plot/hadcrut3vnh/mean:30/plot/hadcrut3vsh/mean:30/plot/esrl-amo/mean:30

It's a really interesting plot, so I thank George for bringing it to the attention of the *massive* readership of the HOTWhopper blog. It demonstrates that the changes in heat in the world's oceans is the tail that wags the climate dog. Remember the '90's when the world warmed rapidly? Remember the ludicrous doom stories about global warming that came out around that time? Well there were all in a positive trend of the AMO. When the trend stopped, global warming stopped. It's that simple.

Right now you'll all be screaming two questions (you are so p.r.e.d.i.c.t.a.b.l.e.):

1) But there's a trend! Outside the oscillations! Yep. There is. What is it RR? What is it huh?

Sure I'll answer. It could be two things:
a) anthropogenic forcing, or
b) changes in cloud cover. Here's a nice plot of hadcrut, which I've inverted, against decreasing cloud cover during the satellite record:
http://oi61.tinypic.com/2ql4i90.jpg

What causes the changes in cloud cover? Stay tuned.

2) But what about the PDO? You were all about the PDO just now RR! Changing your tune?

I asked the question about PDO and AUS temperatures because, gosh, Australia *is next to the Pacific*. Australia is not next to the Atlantic. You can all check on that if you like. And I asked it because I know that ocean temperature changes are THE LARGEST influence on changing air temperatures. So, when you're looking at a large change in air temperatures isn't it logical to ask "Gee, I wonder what sea temperatures were doing around that time?"

No? You don't wonder those things? You just blindly accept whatever garbage you are fed? Welcome to HOTWhopper. And you are welcome to it.

Anonymous said...

Yeah the link worked. I plotted NODC data in Microsoft Excel and used NODC's North Pacific values for my analysis (if that's what you want to call it). Do skeptics ever address this violation of conservation of energy when they talk about PDO?

cabc

izenmeme said...

@- DJ
"I mean, if you had a financial advisor who thought the Dow Jones index was in US dollars, and you politely pointed out to them that it was an index...."

The comparison with a stock market index is more revealing than just showing RR's error.
The Dow Jones or the FTSE index are not a total measure of the whole stock market, it is a selection of the largest parts that can be easily measured and are considered significant and representative components of the stock market.

It is a reification error to think the index therefore represents a coherent or complete, isolated causative agent in the system. Just because some simpler subset of the whole system can be used to gain knowledge of the whole does NOT indicate that simpler, measurable, part is the causative agent for it all.

The simplistic view of causation that some people apply is to think that because X can be measured, and it changes with the state of the economy/climate it is therefore a causative factor for the larger system, rather than just and indicator or convenient measure of the bigger picture.

The foolish economists would conclude from the close correlation between the top 10 companies in a stock market index and the global economy that Shell, Microsoft and others directly shaped the larger economy, rather than being largely dependent upon it.

There is however one important difference between financial markets and climate change. In financial markets the key factor is money, in climate it's the energy. They follow opposite Laws, energy follows the Laws of thermodynamics, it cannot be created or destroyed, it is useful only when flowing from a high concentration to a low and becomes more evenly distributed over time.
Money...

Cugel said...

That's a lot of work, Sue; many thanks.

'Largely cool but diffferent' does say it all about the current PDO 'phase'. If the PDO is positive for a few years now that will become 'Largely indifferent', which would be cool :)

Sou said...

RR, well, you asked the question. It doesn't really matter why you asked it, now that you have the answer.

http://blog.hotwhopper.com/2014/10/heat-heat-waves-and-angry-australian.html

A simple "thank you" would have sufficed.

Sou said...

RR wrote:
"Sou continues lying by saying that there was no spike in PDO at that time. She's either an idiot, or a compulsive liar.

Here's the monthly data: http://www.woodfortrees.org/data/jisao-pdo/from:1910
Here's a plot of the spike: http://oi59.tinypic.com/11w8rom.jpg


He was wrong. I didn't lie and his own data demonstrates that. Incidentally, if RR was referring to the "spike" being the index value of +1.80, that was in May 2014, a whole 16 months *after* that extraordinary January of 2013. The PDO didn't turn consistently positive until 12 months after January 2013.
http://jisao.washington.edu/pdo/PDO.latest

In any case, the PDO doesn't "cause" heat and not in "spikes". Not only that, but a warm phase of the PDO only coincides with a warmer *eastern* Australia. That summer saw record heat over the country as a whole. It's the cool phase that coincides with warmer in the northwest of Australia during the wet season.


RR wrote: "The index was NOT negative all summer! Look at the data! You are in denial. :-D"

RR is mistaken. This is from his own preferred PDO index and shows there was not one positive PDO value during or immediately preceding the summer:
http://jisao.washington.edu/pdo/PDO.latest


Spring 2012

September 2012 -2.21
October 2012 -0.79
November 2012 -0.59

Summer 2012-13 - the summer being discussed

December 2012 -0.48
January 2013 -0.13
February 2013 -0.43

Autumn 2013

March 2013 -0.63
April -0.16
May +0.8

Winter 2013

June -0.78
July -1.25
August -1.04

Ragnaar said...

“Just because some simpler subset of the whole system can be used to gain knowledge of the whole does NOT indicate that simpler, measurable, part is the causative agent for it all.”

+1
CO2 is a subset of the system, is probably the easiest thing to measure and is used to gain knowledge of the whole. By some accounts about all we need to know.

Ragnaar said...

“...essentially saying that observed surface and atmospheric warming is caused by the ocean (specifically the northern Pacific) giving off energy to the atmosphere. This would require the northern Pacific to have lost energy.”

Here's the main energy pathway. Sun to oceans, to atmosphere, to space.
The observed atmospheric warming is partly caused by the oceans giving off energy to the atmosphere. The Northern Pacific or any other ocean can give off more heat while building it. Add plus 2 solar by reduced cloud albedo, store 1 and emit 1.

DJ said...

Geez, this RR is totally out of his depth on this one.

If you have a look at his chart here.
http://oi59.tinypic.com/11w8rom.jpg

He has on the Y label, 'Temp Anomaly C'

He still thinks that the PDO is measured in Celsius units. What a dopey drongo.

Is it any wonder that he thinks that the PDO had a large influence on temperatures of Australia during the summer of 2012-13. When he gets such the simplest of concepts wrong, is it any surprise why the rest of his assertions are so completely off base.

From wikipedia.
"The Pacific Decadal Oscillation (PDO) is the leading empirical orthogonal function (EOF) of monthly sea surface temperature anomalies (SSTA) over the North Pacific (poleward of 20° N) after the global mean SSTA has been removed, the PDO index is the standardized principal component time series"
http://en.wikipedia.org/wiki/Pacific_decadal_oscillation

As Sou has rightly pointed out, the index was negative leading up to the summer, and all during the summer. Also maybe do some research on what an empirical orthogonal function is and how it's NOT measured in degrees Celsius.

As you can see from this image
https://en.wikipedia.org/wiki/Pacific_decadal_oscillation#mediaviewer/File:PDO_Temperature.png

the temperature in Australia is hardly affected by the PDO. It's mostly a North American feature. In Australia, the most dominant index that affects temperature patterns is the ENSO, which was cool/neutral during that summer.

Most of the indexes were on their cool phase during the summer of 2012-13, yet it was a record breaker, highlighting that the influence of AGW was the principle component. (The published studies also confirm this) Despite this, RR still continues to yap on about the PDO, playing innocent and asking a rhetorical question, ""How much of the temperature spike in 2013 was due to the spike in the PDO at that time?" Well the answer is hardly any, considering the PDO normally has very little influence in Australia, and during the time leading up to the summer and during the summer itself, it was in it's 'cool' phase.

Ragnaar said...

The PDO:
Emergent behavior:
http://en.wikipedia.org/wiki/Emergence

If the PDO is real, why is it doing that? Changes to meridional heat transport, changes in ocean heating and cooling, changes in cloud cover might be what happens in a way organized enough to say, it's a cool or warm PDO phase.

“The PDO is a manifestation of spatiotemporal chaos, a “coherent structure” if you will. We can’t predict how long a structure will remain coherent (Tomas (Milanovic) is correct). But as a practical matter, it is a useful scenario to consider that this particular structure will remain coherent for another decade or two.” - Curry 2/11/11

A coherent structure, for instance, the Gulf Stream might be said to be that.

Say the PDO is an oscillator:

“...is that these oscillators are in reality not causally independent but they are ALL just emergent local manifestations of GLOBAL dynamics of the system.” Milanovic 1/04/11

So we can look at the PDO as a result. Since whatever it is is argued to be there, it will now transmit information to other regions such as temperature data that blows in on the wind. Humidity data. So it will to some extent be a cause with some level weight. I think the important point is that it is a result of darn near everything. A local manifestation of that.

Joe said...

What the hell are you trying to say?

Joe said...

RR, what's your point? That energy is created out of the ocean to heat the atmosphere? I'm guessing you believe in perpetual motion machines.

Joe said...

Ragnaar, think about what you wrote and read it. You basically are trying to argue that energy conservation is not violated by violating energy conservation.

DJ said...

"Here's the main energy pathway. Sun to oceans, to atmosphere, to space."

For goodness sake Ragnaar. Can you please just go elsewhere and spout your obvious nonsense.

The pathway is this
Sun -> atmosphere (some reflected) -> ocean + land (some reflected)
ocean + land -> atmosphere (plus back radiation and latent heat) -> space
http://en.wikipedia.org/wiki/Earth's_energy_budget


Look. This is the most basic of concepts with little argument, yet you even stuff that up. You have zero climate knowledge and zero credibility. Everything you post is just a whole lot of words that just make no sense.

Why are you still here? How did you discover this site? Why do you insist on posting gibberish and making a complete fool of yourself every time? You need help!!

BBD said...

RR

He then digs up a graph I posted, and am rather fond of, of the relationship between the AMO [...] and global temperatures

A relationship that you apparently do not understand. As in any technical discussion, it would be useful if you read the links. Here, again, is the relevant discussion of AMO and global average temperature.

You mentioned tails wagging dogs. That is apposite.

BBD said...

You are also apparently confused about cloud. You link the ISCCP data but you need to look at low-level cloud if your focus is albedo and solar flux to the ocean. This is the relevant plot.

What do we see? A slight reduction in global low level cloud from ~2000 on. But this is coincident with a reduction in the rate of surface warming. Let's look at low level marine cloud over the Pacific. Same thing. Slight reduction in LMC over the basin since ~2000 coincident with a flattening in the rate of OHC increase in the 0 - 700m layer. Observations don't support your claim.

Rum Runner said...

@dj
One of the many things I love about Australia is the language. Dopey drongo! How fantastic. It's my new phrase of the day. Here in France the insults are just so mundane in comparison. Usually something scatological, or the occasional "vas enculé de ton vache". Nothing quite so poetic as the Australian vernacular.

Yes, the PDO is an arbitrary scale, not a direct temperature scale. Due to my concern for Sou's failing eyesight, when she couldn't see the rise in the main graph (of AUS temp and PDO) I made a replot showing only the PDO in recent years. I didn't change the Axis labels. My bad. It's derived from de-trended SSTs (which are in C).

I think my question was a valid one. That others disagree is astounding. Ocean temperature changes are the MAIN influence on sub-centennial atmospheric temperatures. I think they explain *most* of the recent warming, and I'm not the only one saying that, for example see: http://link.springer.com/article/10.1007%2Fs00382-008-0448-9 (there's a full .pdf here: http://www.esrl.noaa.gov/psd/people/gilbert.p.compo/CompoSardeshmukh2007a.pdf)

Abstract
Evidence is presented that the recent worldwide land warming has occurred largely in response to a worldwide
warming of the oceans rather than as a direct response to increasing greenhouse gases (GHGs) over land.
Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but
without prescribed GHG changes, account for most of the land warming. The oceanic influence has occurred
through hydrodynamic-radiative teleconnections, primarily by moistening and warming the air over land and
increasing the downward longwave radiation at the surface. The oceans may themselves have warmed from a
combination of natural and anthropogenic influences

And also here: http://onlinelibrary.wiley.com/doi/10.1029/2002GL015191/abstract

Abstract
An analysis of ocean surface temperature records show that low frequency changes of tropical Pacific temperature lead global surface air temperature changes by about 4 years. Anomalies of tropical Pacific surface temperature are in turn preceded by subsurface temperature anomalies in the southern tropical Pacific by approximately 7 years. The results suggest that much of the decade to decade variations in global air temperature may be attributed to tropical Pacific decadal variability. The results also suggest that subsurface temperature anomalies in the southern tropical Pacific can be used as a predictor for decadal variations of global surface air temperature. Since the southern tropical Pacific temperature shows a distinct cooling over the last 8 years, the possibility exists that the warming trend in global surface air temperature observed since the late 1970's may soon weaken.

Here they look at the AMOs influence on climate, and the proportions that can be attributed to anthropogenic vs AMO. They find the "best fit" is AMO plus a TCR of 1.3C:
http://www.earth-syst-dynam-discuss.net/5/529/2014/esdd-5-529-2014.pdf

...cont...

Rum Runner said...

Abstract
The instrumental surface air temperature record has been used in several statistical studies to assess the relative role of natural and anthropogenic drivers of climate change. The results of those studies varied considerably, with anthropogenic temperature trends over the past 25–30years suggested to range from 0.07 to 0.20 ◦Cdecade . In this short communication we assess the origin of these differences and highlight the inverse relation between the derived anthropogenic temperature trend of the past 30years and the weight given to the Atlantic Multidecadal Oscillation (AMO)
as an explanatory factor in the multiple linear regression (MLR) tool that is usually employed. We highlight that robust MLR outcomes require a better understanding of the AMO in general and more specifically its characterization. Our results indicate that both the high- and low end of the anthropogenic trend over the past 30years found
in previous studies are unlikely and that a transient climate response with best estimates centred around 1.3◦C per CO2 doubling best captures the historic instrumental temperature record.

And of course my fantastic graph of the AMO and NH & SH temperatures: http://www.woodfortrees.org/plot/hadcrut3vnh/mean:30/plot/hadcrut3vsh/mean:30/plot/esrl-amo/mean:30

There's many other similar papers. So the debate, outside the bubble of HOTWhopper, is only on proportion. Is it 100% Anthropogenic Vs 0% oceanic? 50%/50%? 25%/75%? 5%/95%? It's only those who "are so blind they cannot see" (Hi Sou!) who prescribe recent warming solely to ACO2. Hey, I'm fine if the answer to my question is "no". Not a problem, as long as it's backed up. I'm not fine with people ignoring the evidence and not even entertaining the possibility, seeing as oceanic influences explain so much of global, and regional temperatures.

Rum Runner said...

@BBD

You must have posted the wrong link. It's to a blog by Tamino. And it's pure bullshit.

He's essentially suggesting that the AMO is now only influenced by ACO2. The AMO has been going for thousands of years! With ACO2 and without it. We have good proxies for the last thousand at least. So he fails, in spectacular fashion.

BBD said...

You must have posted the wrong link. It's to a blog by Tamino. And it's pure bullshit.

The data show that the AMO is influenced by global temperature change. If you disagree, you are going to have to come up with a substantive demonstration that the analysis is wrong. "Pure bullshit" will not suffice. If you cannot do this, then you will concede the point.

Rum Runner said...

@BBD

"A slight reduction in global low level cloud from ~2000 on"
A slight reduction! (Thinks: "maybe BBD and Sou can get a bulk discount at the opticians..") Reduction in cloud of just a few percent is the equivalent (opposite) forcing of all the ACO2 we've ever produced (and that's assuming high sensitivity figures)! A percent here or there matters. A lot. It was well covered in the Spencer/Baswell Vs Dessler exchanges.

Rum Runner said...

@BBD,

I despair! Tamino being out by a few thousand years not good enough! 0_o

BBD said...

RR

A slight reduction in low marine cloud coincident with a reduction in the rate of surface warming and a reduction in the rate of Pacific OHC increase.

The exact opposite of your claim.

If you are as confused and adrift as you appear to be, stop commenting.

BBD said...

Reduction in cloud of just a few percent is the equivalent (opposite) forcing of all the ACO2 we've ever produced (and that's assuming high sensitivity figures)!

This is back to front. The argument is that reduced low marine cloud cover increases solar SW flux to the surface and increases temperature.

Can you confirm that this is - or is not - your understanding before we continue any further.

Rum Runner said...

@BBD
"The exact opposite of your claim."

First, My claim is exactly what I said it was. Not what you think I said, or what you perceive as I've said, or you imagine what I said. My claim is what I said. It's a common theme in the blog for people to ascribe thing to people they didn't say. So I'll just nip it in the bud here - just in case.

Second, My claim was less cloud higher temperatures. : http://tinypic.com/view.php?pic=2ql4i90&s=8#.VDkL5CU6OXo,

And Third it's entirely consistent with the Pacific OHC graph you posted! (There's the caveat in that you've only posted OHC for the Pacific while the plot I posted was for Global temperature & Global cloud)

So I am confused, yes, but by your bizarre logic of posting graphs that back me up to "show" that I'm wrong!

Rum Runner said...

"Can you confirm that this is - or is not - your understanding before we continue any further. "

Ahh, you've been listening to those mischievous children at Skeptical Science haven't you? Those of the clouds are a net positive forcing baloney. http://www.skepticalscience.com/clouds-negative-feedback.htm

"evidence is building that clouds will probably cause the planet to warm even further, and are very unlikely to cancel out much of human-caused global warming. It's also important to remember that there many other feedbacks besides clouds. There is a large amount of evidence that the net feedback is positive and will amplify global warming."

Tee hee!

Compare that with:

"The latest results from ERBE indicate that in the global mean, clouds reduce the radiative heating of the planet. This cooling is a function of season and ranges from approximately -13 to -21 Wm-2. While these values may seem small, they should be compared with the 4 Wm-2 heating predicted by a doubling of atmospheric concentration of carbon dioxide."

from: http://itg1.meteor.wisc.edu/wxwise/museum/a2/a2cloudforce.html

See also:

"Of all cloud forms, low-level marine clouds exert the largest impact on the planet’s albedo2. For example, a 6% increase in the albedo of global marine stratiform clouds could offset the warming that would result from a doubling of atmospheric CO2 concentrations"

from: http://www.nature.com/ngeo/journal/v7/n9/abs/ngeo2214.html

So more marine cloud => less warming. More generally more cloud => less warming. As I've said, and for some bizarre reason you seem to be arging against! Maybe you are confused that you didn't notice that my plot of Hadcrut is INVERTED?

BBD said...

RR

My claim was less cloud higher temperatures.

Which is contradicted by observations. Read my comment again. Reduced global and reduced Pacific basin low cloud cover are respectively coincident with a reduction in the rate of surface warming and a reduction in the rate of OHC increase in the 0 - 700m layer of the Pacific.

And Third it's entirely consistent with the Pacific OHC graph you posted!

No, it isn't. Observations show the opposite. See above. Read the words and click the links.

(There's the caveat in that you've only posted OHC for the Pacific while the plot I posted was for Global temperature & Global cloud)

I posted two links to ISCCP cloud data, one for global low cloud and one for Pacific basin low cloud. Read the comment properly.

I repeat: your argument is incompatible with observations. Not for the first time here.

Robert Murphy said...

"Those of the clouds are a net positive forcing baloney."

RR, you are confusing a forcing and a feedback. Skeptical Science in the link you gave was talking about cloud feedbacks, while the link you provided here http://itg1.meteor.wisc.edu/wxwise/museum/a2/a2cloudforce.html
is talking about radiative forcings. Nobody is saying that clouds aren't a net negative forcing. That's completely consistent with the claim that in a warming world clouds will likely be a net positive feedback. You are confused about the basic terminology.

Rum Runner said...

Me: "My claim was less cloud higher temperatures."
You: "Which is contradicted by observations"

Sheesh. Here's the graph for the THIRD time: http://oi61.tinypic.com/2ql4i90.jpg

The blue/green lines are decreasing cloud, and the red line is Hadcrut 3 (I did this graph quite a while back, I should re-do it with Hadcrut 4, but I doubt it would be materially changed.)

The red line is INVERTED. So down means hotter. So FROM THE DATA less cloud => hotter.

So my claim is CONFIRMED not "contradicted by observations."

"No, it isn't. Observations show the opposite. See above. Read the words and click the links."

I've read the words. I've clicked the links. You should try the same with mine. Your OHC (Pacific only) graph shows OHC increasing when the cloud goes down. I.e. less cloud => increased OHC! Consistent with my claim.

Are you arguing therefore (at odds with the papers I linked to) that clouds are a net positive forcing? Because data says "no". You should also take up your case with Washington State university who say they are a net NEGATIVE forcing of between -13 to -21 Wm-2., and see the other data they present. And you should be taking up your case with the peer-reveiwers at Nature, because I agree with them, and you - apparently - disagree.

In spite of the evidence quite why you want to take on me, and both Washington State, and the august journal Nature I can only guess at. I can only assume you are wanting to argue against me because you perceive me to be " a denier" (although quite what I'm supposed to be "denying" is never made clear). It's fudging your judgement.

George Montgomery said...

Oops! It would appear that I've arrived late to the party.

"Now, it seems I have another stalker! I am rather gorgeous …. Don't take it personally. Actually one's only trying to do one's job of being "p.r.e.d.i.c.t.a.b.l.e." while you're trivialising stalking. Tsk. Tsk. "Don't trust the voices in your head. Not all of them are right." At least I'm never alone unlike ... Right now, the big booming voice is arguing with the tiny squeaky voice and the metallic voice while the others are singing 'a capella'. And what makes you think that they're not all Rhodes scholars? Tsk. Tsk. By now you're probably starting to see where this is all going for you.

"because I know that ocean temperature changes are THE LARGEST influence on changing air temperatures." No it's not. I'd say that'd have to be the sun and the earth's rotation on an inclined axis. Day, night, summer, winter; think about it. You're venturing into Bill O'Reilly territory. Tsk. Tsk. "It's a great plot. Here it is: When the (AMO) trend stopped, global warming stopped." Since you've used the words "AMO trend" here's your graph with trend lines". Actually using 'Tisdale eyeballing' (a registered trade mark?) and your "great plot", behold, global temperature anomalies are driving the AMO. Just follow your own technique and pick a time interval, any time interval that suits and ignore the rest. Tsk. Tsk.

"Well there (que?) were all in a positive trend of the AMO. When the trend stopped, global warming stopped. It's that simple." So simple that it beggars belief that one ocean, the Atlantic, controls global weather to the exclusion of the Pacific, Indian, Southern and Arctic Oceans. Which flows on to the "because, gosh, Australia *is next to the Pacific*" and gosh, so are Chile, Peru, China and 26 other countries next to the Pacific. Is the PDO warming effect exclusively Australian or does it extend uniformly to the other 29 countries around the Pacific Rim and the island countries of the Pacific? So, there's an oversight in your dissertation. Tsk. Tsk. "Here's a nice plot of hadcrut, which I've inverted, against decreasing cloud cover during the satellite record:" Back at you, here's a "nice plot" of global average temperatures against estimated global numbers of pirates, which axis has been inverted. Conclusion: the increase in pirates in Africa and Asia around the turn of the century has led to the so-called 'pause in global warming' (one of the aspects of AGW). Back to "that big solid thing. That's called the earth." High level cloud? Low level cloud? Daytime cloud? Night time cloud? Now there's an oversight in your graph. Tsk. Tsk.

By now you can probably figure out what brought about this comment. Like others here, I don't "blindly accept the rubbish (you) feed me." I just don't. I can see that you're going to have trouble living with that but you'll just have to. Otherwise, it'll get between you and your sleep. Good night and may your God go with you.

BBD said...

RR

Okay, baby steps.

What happened to the RATE OF INCREASE in surface warming post ~2000?

Did it:

1/ Increase
2/ Slow
3/ Stay the same as the rate 1980 - 2000?

We know that the answer is (2).

Now your claim is that the slight reduction in low cloud cover since ~2000 should have caused and INCREASE in the rate of surface warming (1). But it *didn't*.

Hypothesis falsified by observations.

Exactly the same is true of Pacific Ocean OHC 0 - 700m. Hypothesis falsified by observations.

For your argument to have survived this empirical test, the rate of warming (and Pacific OHC increase) post-2000 when low cloud cover reduced slightly would have to have been GREATER than that of the decades 1980 - 2000. Your claim is that less cloud should lead to an increased rate of warming. It didn't. The rate of warming *slowed* when cloud cover reduced.

I cannot make it any simpler than that. The cognitive leap to understanding what is in front of you is yours to make.

One possible explanation for what has happened is that clouds have two sides. The top modulates albedo and SW flux to the surface during daylight. The bottom modulates the rate of surface cooling by absorbing and re-radiating IR, predominantly at night. The two effects may more or less cancel out, especially for minor changes in LMC cover. It may well be that other factors (eg wind-driven ocean circulation) have had a much larger effect on GAT since ~2000.

Rum Runner said...

@Robert Murphy

Ok sloppy language on my part, but good sniping on yours. Clouds can be a forcing and a feedback. My points stand. Less cloud => more warming.

BBD said...

Your OHC (Pacific only) graph shows OHC increasing when the cloud goes down. I.e. less cloud => increased OHC! Consistent with my claim.

No, it doesn't. It shows OHC increase from ~1980 to 2000 and a levelling off after ~2000. I'm not going to repeat this again. If you repeat your false claim again, I will ask that you are moderated for lying.

BBD said...

Before more time is wasted, it's worth remembering that the trend in ISCCP cloud cover data is very likely to be spurious.

That would be another reason why the expected warming attendant on a reduction in low cloud cover failed to materialise. There was no reduction in low cloud cover.

BBD said...

From Evan et al. (2007):

The International Satellite Cloud Climatology Project (ISCCP) multi-decadal record of cloudiness exhibits a well-known global decrease in cloud amounts. This downward trend has recently been used to suggest widespread increases in surface solar heating, decreases in planetary albedo, and deficiencies in global climate models. Here we show that trends observed in the ISCCP data are satellite viewing geometry artifacts and are not related to physical changes in the atmosphere. Our results suggest that in its current form, the ISCCP data may not be appropriate for certain long-term global studies, especially those focused on trends.

Joe said...

I don't think the paper (at least the 2014 one that I looked at) says what you think it says. From the paper:
"One other outcome of these MLR analyses is that most of the temperature increase over the past 100 years is of anthropogenic origin, whether the AMO is included or not and whether the anthropogenic shape is linear or follows the forcing estimates. This indicates that there is no combination of natural factors that can better match the observed temperature pattern than one with a large anthropogenic influence"

Rum Runner said...

@ George Montgomery

And breathe! I enjoyed that. You write well.

* Largest influence on air temperatures => should be sub-centennial changes as I mentioned elsewhere. I'd also concede LOD variations, major volcanic eruptions, and probably some other things including solar variations. I congratulate you.

* AMO with trend lines! Oh dear. I can give you any trend you like with a sine wave. Take your pick. The point being that trend lines are meaningless with an oscillation. The current peak of the AMO cycle means that any trend line you choose to draw (over say a couple of decades long) will end at the peak of a cycle. If you are really clever you can do it from the trough of one cycle to the peak of another. Wow! Look at this trend!

http://www.woodfortrees.org/plot/esrl-amo/from:1960/mean:30/plot/hadcrut3nh/from:1960/mean:30/plot/hadcrut3nh/from:1960/trend

The AMO is upto ~80 years long for one cycle. The current warm-period (let's call it the '80's to 2010's) co-incides exactly with a rising AMO. So drawing a trend line anywhere in there is going to be bogus.

"Like others here, I don't "blindly accept the rubbish (you) feed me." I just don't. I can see that you're going to have trouble living with that but you'll just have to."

:-D Fair enough. It's just that I haven't seen any evidence of it yet on the blog. I'll just have to keep looking.

Rum Runner said...

@BBD

"Now your claim is that the slight reduction in low cloud cover since ~2000"

Now, remember what I said earlier about not getting confused about what I claimed, and what your inner voice said that I claimed?

Here we are again:
"Your claim is that less cloud should lead to an increased rate of warming."

I said nothing about rate. My claim (and I really can't believe I have to repeat this again) is:

Less cloud => warmer
More cloud => colder
As the data shows. It's that simple. Comprende Amigo?

It is not as you so desperately seem to want it to be anything to do with Increased rate of loss of clouds or accelerated cloud accumulation, or any other contortion you want to make.

Sou said...

RR what are you rabbiting on about now? The oceans can't heat up the air all by themselves all of a sudden out of the blue, not unless something is heating the oceans.

Nor do I know what point you were trying to make with your AMO chart. It goes up and down, so what? What do you think the "O" stands for?

From your WFT chart, going from the first peak of the AMO to the last peak so far, global surface temperatures have risen from around minus 0.2 to plus 0.6 degree Celsius - around 0.8 degree Celsius. Yet the AMO peak hasn't shifted, so that extra heat isn't magically coming from the Atlantic.

I don't know the point you are trying to make, but if you are asking if the oceans can somehow cause global warming and that greenhouse warming is minimal or non-existent (Tisdale's goblin fires in the oceans or similar), then you've got a lot more reading to do on the subject. Not here - try reading up on the greenhouse effect.

Here it is with HadCRUT4:
http://www.woodfortrees.org/plot/hadcrut4nh/mean:12/plot/hadcrut4sh/mean:12/plot/esrl-amo/mean:12

DJ said...

@RR.

You should become a politician, as you have certainly nailed down the art of obfuscation, misdirection and not answering the question. The papers you presented, although very interesting, do NOT actually pertain to the question at hand. That is, how much of the record breaking heat of Australian summer of 2012-13 can be attributed to the PDO.

You have now, through the art of misdirection, are suggesting something else with ANOTHER ill-posed rhetorical question. "Is it 100% Anthropogenic Vs 0% oceanic? " Perhaps the answer is that it is 100% Anthropogenic AND 100% oceanic.

For instance, the Gilbert P. Compo paper suggests that the land warming is caused by a 'hydrodynamic-radiative teleconnections', but the abstract ends with 'The oceans may themselves have warmed from a combination of natural and anthropogenic influences.' So to completely rule out anthropogenic influences, as you seem to have done, is a misrepresentation of the paper.

Then there is the other paper by G. R. van der Werf, that states,

"One other outcome of these MLR analyses is that most of the temperature increase over the past 100years is of anthropogenic origin, whether the AMO is included or not and whether the anthropogenic shape is linear or follows the forcing estimates. This indicates that there is no combination of natural factors that can better match the observed temperature pattern than one with a large anthropogenic influence."

Basically, the observed global warming is NOT caused by the AMO, but by anthropogenic influences.

I don't know what you are trying to achieve, but the papers that you present are within the scope of the current consensus, and do not further support any of your previous, or new assertions. (whatever they are, as you seem to flip-flop and will not commit to a position with all your ill-posed rhetorical questions.)

BBD said...

RR

There's nothing more to say. Your entire argument was based on a spurious trend in the ISCCP data.

Can't you read?

BBD said...

Sou

Less cloud => warmer
More cloud => colder
As the data shows. It's that simple. Comprende Amigo?


Enough now?

BBD said...

Compo & Sardesmukh (2007) illustrates positive water vapour feedback:

Atmospheric model simulations of the last half-century with prescribed observed ocean temperature changes, but without prescribed GHG changes, account for most of the land warming. The oceanic influence has occurred through hydrodynamic-radiative teleconnections, primarily by moistening and warming the air over land and increasing the downward longwave radiation at the surface.

It's a good example of how CO2 forcing is leveraged by WV. C&S fluffs attribution somewhat with its:

The oceans may themselves have warmed from a combination of natural and anthropogenic influences

But nothing's perfect. Otherwise what Sou said. OHC has risen for decades in all major ocean basins. So a forcing is being applied to all major ocean basins. We know it ain't the sun and it ain't spurious trends in LMC cover, which leaves the exhaustively-calculated increase in RF from CO2 and other GHGs.

Occam's Razor.

Rum Runner said...

@ Sou:
"RR what are you rabbiting on about now? The oceans can't heat up the air all by themselves all of a sudden out of the blue"

Sou, I take it that was a joke? Are you suggesting that heat exchange between the oceans and atmosphere doesn't take place? No convection? No evaporation? No solar radiation heating the ocean? No LW radiation cooling the ocean (via evaporation)? No conduction? So yes, Sou, the oceans can heat up the air all by themselves.

"not unless something is heating the oceans."

Uh. The sun! Which, as we've had less cloud in recent years... http://oi61.tinypic.com/2ql4i90.jpg

"Nor do I know what point you were trying to make with your AMO chart."

It's a great plot isn't it? The take home is simple: the atmosphere gets bossed by the oceans. Yes, as I said elsewhere there's also a trend due either to anthropogenic, or as above, less clouds. What’s the breakdown of Anthro/Cloud Vs Ocean changes? We'll know in 2030 at the bottom of the AMO cycle.

BBD said...

Well, would you look at that. Another ocean basin where OHC stopped increasing with the imaginary decrease in LMC at the turn of the century...

N. Atlantic OHC 0 - 700m layer

AMO fans should notice that N. Atlantic OHC increases from ~1970 to ~2000, so it's fairly safe to say that the energy driving modern warming is not coming out of the N. Atlantic. Or OHC would have fallen over the same period.

Are some of the basics of physical climatology beginning to fall into place yet?

Rum Runner said...

@DJ,

"You should become a politician"

Ugh no!

"as you have certainly nailed down the art of obfuscation, misdirection and not answering the question"

Firstly: You asked a question? I didn't see one. Secondly your honour: Projection!

"ANOTHER ill-posed rhetorical question. "Is it 100% Anthropogenic Vs 0% oceanic? ""

Well that wasn't quite my question. It was more like "what percentage is it?" 100% of both is impossible and illogical.

"So to completely rule out anthropogenic influences, as you seem to have done, is a misrepresentation of the paper."

..and that's a misrepresentation of what I said! There's a lot of that about. You continue on that vein, selectievly quoting the last of the three papers I selected at random of the many similar available. Let's look at the conclusions:

"Conclusions
Assuming that at least part of the AMO is of natural origin and given that it has a substantial temperature cycle and large footprint, it should be included in MLR studies as an explanatory variable. This will lower the anthropogenic temperature trend for the past 30years compared to MLR studies neglecting the AMO as shown by Zhou and Tung (2013) and Chylek et al. (2014). However, our results indicate that the degree to which this is the case depends on the choice of AMO description. Using detrended NA SST indicates a strong role for the AMO and thus a relatively low anthropogenic trend but these observations are contaminated by other factors influencing NA SST. More sophisticated AMO descriptions indicate a similar or smaller role for the AMO, and consequently potential higher anthropogenic trends for the past 30years. Our results thus imply that a better understanding of the AMO is required to increase our confidence in the outcomes of these MLR exercises, especially when considering relatively short periods when fluctuations in multidecadal oscillations such as the AMO do not average out."

So there we have it. Oceans influence air temperatures. Now I wonder if the spike in AUS temperatures in 2012/13 was due to a spike in the PDO at that time...?

Anonymous said...

I wouldn't be too concerned...I'm sure our Rum-rum-rum Runaway will dive back into his rabbit hole sooner than later. Devastating rebuttal to Tamino notwithstanding...

Ragnaar said...

Add plus 2 solar by reduced cloud albedo, store 1 and emit 1.
What part of this violates energy conservation?
The oceans on average have warmed as has the atmosphere.

Billy Bob said...

BBD, I can't for the life of me see what you are driving at. RR has made a clear statement backed by the graphs you yourself posted. Cloud has reduced only slightly, true, but that did not occur in a linear fashion. It was relatively stable till around 91, after which it reduced until around 2000-2002, and since then, again relatively stable.

OHC was up and down prior to 1990, but generally around an average of -1, after which it began rising until around 2000, where it has since settled at a around an average of +0.2.

RR is not commenting on rates or anything like that - he simply observes that as cloudiness decreased, OHC increased. What the heck is so hard to follow about that?

Of course the long term linear trends may not indicate exactly the same thing, but this is where your preoccupation with linear trends overwhelms your ability to see what's right in front of you.

Sou said...

Rum Runner - no, it was no joke, as you yourself recognised half way through your comment when you quoted me saying "not unless something is heating the oceans".

You claim that the sun increased radiation so much that it caused a rise in Earth's temperature of nearly one degree Celsius over the past century. Well, that's wrong. The sun didn't increase its output by anything like that. As you say, the sun has decreased output - yet the earth hasn't cooled down. The oceans haven't got any colder, they are still accumulating heat.

You claim that clouds have suddenly decided to behave differently all by themselves for no reason. Well they don't. If clouds change then something else must have changed to cause that. And it wasn't the sun.

At least you are now acknowledging that greenhouse gases make a difference, despite you trying to pin most of it onto clouds and the sun.

You've got to answer the question: what is different now that is causing the earth to heat up. That is probably going to bring about changes not seen since Homo sapiens first emerged onto Earth a couple of hundred thousand years ago? That will probably be ten times faster warming than has been seen in 65 million years.

http://news.stanford.edu/news/2013/august/climate-change-speed-080113.html

It's the fact that we've dug up long-sequestered carbon and are pouring it into the atmosphere. It's upset the balance. Energy is not in balance. There is a lot more staying within the earth system now instead of equal amounts coming in as are going back to space. The oceans are dropping pH and heating up, ice is melting rapidly, the air is getting hotter as is the land surface. Patterns of weather are changing.

I can guess why you spend so much time trying to find ways to "refute" science - it offends the image you have of things where humans can do what they like without any consequences. The earth is telling us we can't.

Sou said...

Rum Runner: "Well that wasn't quite my question. It was more like "what percentage is it?" 100% of both is impossible and illogical. "

The oceans don't get hot all by themselves. Something else has to cause them to heat up. The only way the oceans can heat up the atmosphere is if they get hotter themselves, otherwise they've pretty well been in equilibrium with the air for the past few thousand years - until recently.

As for attribution, it's likely that we have caused all and probably more than all of the warming since the 1950s, at least. We've also caused cooling which has offset the "more" to bring it back to 100% net.

The only other thing that could cause warming is the sun, and earth hasn't been getting any more incoming solar radiation since the 1950s, in fact it's declined a tad. Yet the air and the land and the oceans have kept on getting hotter. Ice has been melting faster and faster. Seas have been rising more and more.

We have been putting up a barrier reducing the amount of energy that escapes back to space. That's what is causing earth to heat up. It's not the oceans magically warming up all by themselves and heating the air without letting radiation escape to space. It's greenhouse gases that are slowing the rate at which radiation goes out to space.

We've caused probably more than 100% of the warming plus a bit of cooling (from aerosols). The net effect is that we've probably caused exactly 100% of the warming.

http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/

http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/sep/15/97-vs-3-how-much-global-warming-are-humans-causing

Sou said...

@ Billy Bob - as BBD wrote:

There's nothing more to say. Your entire argument was based on a spurious trend in the ISCCP data.

Can't you read?


RR has been busy trying to pin global warming onto "anything but CO2".

He started with the PDO, then he shifted to the AMO, then he shifted to "it's clouds".

He's just another nutter from deniersville. Or does your preoccupation with tone "overwhelm your ability to see what's right in front of you".

BBD said...

Billy Bob

BBD, I can't for the life of me see what you are driving at. RR has made a clear statement backed by the graphs you yourself posted.

No, he hasn't.

DJ said...

RR wrote "Oceans influence air temperatures. Now I wonder if the spike in AUS temperatures in 2012/13 was due to a spike in the PDO at that time…?"

Yes. Oceans do influence air temperatures. This is not news. Now, with regard to the PDO we know that during it's negative phase, the PDO will cool Australia by about 0.3C and during it's positive phase it will warm Australia by about 0.3C. (In parts of North America and Alaska this is much larger, about 1.5C) In regard to ocean temperature cycles, the ENSO has a much bigger effect, cooling Australia by about 1C during La Nina (the negative phase) and warm Australia by about 1C during El Nino (the positive phase). During 2010 and 2011 Australia had a record La Nina, causing massive flooding and wiping out the temperature anomaly caused by AGW (many Australian deniers went all ice age cometh during this time).

Now given that preceding the summer of 2012/13 and during the summer, the cooling effect of the PDO decreased from about 0.3C to about 0.1C (This is the 'spike' that RR keeps referring to, even though during the entire time the index was negative/cooling), the cooling effect of the PDO was minimal.

Look, over the last 100 years, Australia has also had 100 summers, and in those summers the PDO has been either in a positive, neutral or negative phase. Yet it has only been very recently, that the summers have now become anomaly hot, while the effects of the PDO has stayed the same. For the PDO to also now have an abnormally high effect and have a large influence on the summer of 2012-13, you need to provide a physical mechanism for this change in behaviour. So RR, are you able to provide us with a study which suggests that? If not, your argument falls flat on it's arse.

Ragnaar said...

Sutton's Law: “The law is named after the bank robber Willie Sutton, who reputedly replied to a reporter's inquiry as to why he robbed banks by saying "because that's where the money is."

Our oceans cover about 2/3s of the planet. When we look for the energy, we look there. Land is lacking in energy storage. As was quoted: “A remarkable characteristic of this index (the PDO) is its tendency for multiyear and multidecadal persistence, with a few instances of abrupt sign changes. Based on a variety of studies, sign changes beginning in 1925, 1947, and 1977 have been labeled regime shifts.” While I'd say land does experience regime changes (droughts, heavy annual precipitation, see Australia) I think the larger player is the oceans. They are more variable and have greater reserves than land. It would be reasonable to assume a big controller (though not absolute) of oceanic regions clouds is the oceans. During the hiatus, a number of people are looking at that oceans for what some call the missing heat. I am not aware of many of them looking at land and atmosphere for the missing heat.

I am not saying anything about the PDO related to Australia's recorded heat. However an answer could be expected to include the oceans. The PDO currently is the wrong sign for my taste. Bouncing to warm lately. It may be reacting to the maybe, kinda, maybe El Nino. As Sou graph shows, it's confused. If it doesn't stick in the cool phase, then what? Will the system transition into another regime and will that be a warming one?

Sou said...

At least 90% of the extra energy being accumulated on earth is going into the oceans.

http://www.oceanscientists.org/index.php/topics/ocean-warming

DJ said...

I notice that in the image that RR provided, he tried to correlate HadCRUT3 with ISCCP cloud cover data. (Which has been the denier favourite of all the cloud cover datasets).

I don't know what it is with RR, but he will answer the question being posed with another feigned and unrelated rhetorical question, his latest one being that global warming is now caused by a reduction in cloud cover, and has used a flawed data set to do so.

The ISCCP dataset is flawed.
See one of many analyses here.
http://www.aos.wisc.edu/~dvimont/Papers/Evan_etal_GL028083.pdf

Look, there are much better datasets, which was used in this analysis.
http://meteora.ucsd.edu/~jnorris/reprints/Loeb_et_al_ISSI_Surv_Geophys_2012.pdf

We know it is much better as there is a strong correlation between outgoing LW and cloud cover, which fails with the ISCCP dataset.

Using a dataset which better matches with other datasets reveals that in fact the trend in the ISCCP is spurious, and there has in fact been NO trend in cloud cover, totally throwing out the conjecture that global warming is as a result of cloud cover changes. There has been no trend in cloud cover changes, yet the earth has still warmed, providing conclusive evidence that it's not a result of cloud cover changes, but something else. The only explanation that is able to explain all the other changes noticed, like a decreasing trend in stratospheric temperatures, is anthropogenic greenhouse gases. If global warming was caused by a decrease in albedo, caused by a lowering of cloud cover, there would be also a rising trend in stratospheric temperatures. But the exact opposite is occurring, throwing RR's conjecture out the window.

But does RR take any notice of these observations? No. He is ideologically stuck in the mud, unable to move, despite the overwhelming against him. This is your typical reaction by a denier.

Sou said...

Good work, DJ.

I notice that RR didn't acknowledge his "mistake" about the PDO index, where he claimed it went positive over the Australian summer of 2012-13. Nor did he apologise for labelling me a liar when I demonstrated he was wrong, using the same dataset he favoured.

Deniers aren't just wilfully ignorant, they are a deceitful lot, aren't they. And overly vocal.

Rum Runner said...
This comment has been removed by a blog administrator.
Joe said...

Thanks Sou. And again, I have no idea what Ragnaar is saying. As far as I can tell, he's saying that an internal system (earth including atmosphere) can warm itself by moving energy around in the oceans (similar to Tisdale). That violates the conservation of energy. There has to be an external forcing. It can't be increased energy from the sun because solar radiation has been on the decline for decades. It could be decreased energy leaving the system...and that is the only possible solution (that agrees with physics). IOW, additional CO2 trapping heat from leaving the internal system. Moreover, that additional heat storage has long been predicted by physicists because a CO2 driven greenhouse effect is what keeps our planet from looking like a snowball. Add more CO2 - guess what, temps go up. It's just basic physics.