Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

The Impact of "Small" Volcanic Eruptions on Earth's Climate 11

Status
Not open for further replies.

Maui

Materials
Mar 5, 2003
1,908
These "small" volcanic eruptions are being viewed by some scientists as potentially having a greater influence on earth's climate than was previously believed:


Please do not allow the vitriolic verbal pyrotechnics of your fellow contributors overshadow the points that you are attempting to make in your replies.

Maui
 
Replies continue below

Recommended for you

"What’s more, you know what actually is an argument from ignorance? To say “the absence of evidence is evidence of the opposite”. For example, “I don’t know that ENSO has no long-term influence on climate (because I haven’t read the science on the matter), therefore it has a major long-term influence on climate."

I have not said that the ENSO must leave a long term trend. You are the one arguing that it does not based on models that don't work. And there is evidence to suggest that it does, its effect on cloud feedback, relative strength of the phases, hell even Trenberth found that you cannot linearly filter out the ENSO because it leaves a positive residual. You assume that I haven't researched this. I've researched it more than you. I'm just not a human link machine because I have more fun poking holes in the logic and lack of first truths from sophists like yourself.

You claimed it has no long term trend. The burden of proof is on he who makes the argument not he who refutes it. Your attempt to shift the burden is another logical fallacy on your part.
 
Data: Algorithms:
Their conclusions: and
TTFN
faq731-376
7ofakss

Need help writing a question or understanding a reply? forum1529

Of course I can. I can do anything. I can do absolutely anything. I'm an expert!
 
"Your claim that a GCM can accurately model the ENSO when dedicated ENSO models do a poor job is the fallacious." ... i don't think rconnor was saying that GCMs can predict ENSO events, i think he's saying that including their effects improves the accuracy of GCM predictions.

but i agree with your 2nd post, ENSO events affect the "data" we're reading in ways we can't quantify, so we can't really say ENSO effects are irrelevant. I guess we can say we haven't expressly tried to model them.


another day in paradise, or is paradise one day closer ?
 
"i don't think rconnor was saying that GCMs can predict ENSO events"

That was not my point. The models dont even correctly model the nature of the ENSO. The way this past ENSO played out and what the models predicted were in stark contrast. ENSO's are not deterministic. How they actual play out is unpredictable there are certain characteristics that are more consistent than others but you cant say with any certainty how an ENSO cycle will play itself out.

Like I showed in the gif I linked the 4 best models chosen by Risbey were by no means an accurate representation of actual observations. In terms of spatial distribution of heat they are almost mirror images of each other. The models show warming where the observations show is cooling and cooling where there is warming. Its only on the average are they close to each other.

The claim "This is exactly what Risbey et al 2014 looked at and they found that models that were in phase with the actual ENSO state matched observed temperatures extremely well. " Is demonstratively false. In no way are they in phase.
 
Another point to Risbey which seems to be endemic to climate science and soft science in general. They define their index of the ENSO as the long term trend Nino 3.4 index. The problem is that while Nino 3.4 is the standard index for identifying ENSOs it is a short term index. 5 consecutive months exceeding 0.5C in the Nino 3.4 region is the general definition of an el nino or la nina. The problem is that in the long term this relationship breaks down.

Another point to Risbey which seems to be endemic to climate science and soft science in general. They define their index of the ENSO as the Nino 3.4 index.

Two long term equal Nino 3.4 trends. In one the El Nino is dominant in the other the La Nina is dominant.

figure-5.png


As you can see there is no correlation between the long term trend of the Nino 3.4 index and the dominance of El Nino or La Nina. As I said it’s a short term index.

Now when this happens its often chalked up to a mistake but my father was a lawyer. He often told me ‘The ball drops once you take notice. The ball drops twice you say hold on a minute.’

In the years I’ve studied this field I’ve gone from skeptical to cynical. The question that pops into my mind these days is ‘Did they make their choice priori or post hoc? Just how many different ways of tackling this problem did they use before settling on this method? How many other methods were tried but discarded because they did not produce the desired result?’
 
I had originally drafted a different reply, where I touched on the specific comments made by GTTofAK. However, I’ve thought better of it. GTTofAK is dancing around the point, so me replying to each superfluous (and largely incorrect) comment would only detract from the discussion. So, instead, I’ll provide a detailed post on the actual point of the matter:

Does ENSO have the ability to have a major impact on the long-term trend of global climate?

--------What is ENSO and What Does it Do?-------
To answer this, we need to understand what ENSO is and what it does. A nice rundown of ENSO can be found here or here, from NOAA. Some history on ENSO research can be found here. The write-up on the impacts of ENSO can be found here.

In brief, ENSO relates to the weakening (during El Nino) and strengthening (during La Nina) of Pacific equatorial trade winds. During El Nino years, when trade winds are weak, warm water that usually pools in the West Pacific moves closer to the surface, where it interacts with the Atmosphere more readily, and is transported eastward. During La Nina, the strong trade winds cause warm water to pool deeper in the Western Pacific and causes stronger upwelling of cold water in the Eastern Pacific.

ENSO has a profound impact on seasonal climate variability in certain regions. Due to the positive and negative impacts of ENSO on agriculture and society in certain regions, the ability to accurately predict the ENSO state and effect on regional-seasonal weather is very important. Currently, our ability to predict ENSO and its specific seasonal impact on weather in specific regions is rudimentary and often not that accurate. Much effort is being put in to improve our knowledge in this area.

However, it’s very important to differentiate between predicting seasonal weather variability in certain regions and modeling long-term global climate. Our inability to predict ENSO does not, on its own, mean that long-term climate projections are flawed. In order for our inability to predict ENSO to be a significant issue for long-term climate projections, ENSO must have a long-term impact on climate trends. However, logically, the burden of proof is on the asserter (i.e. those that support the anthropogenic climate change theory), so it should be phrased the opposite way – in order for our inability to predict ENSO to NOT be a significant issue for long-term climate projections, ENSO must NOT have a long-term impact on climate trends. The science supports this for a variety of reasons, which I’ll outline below.

--------Reasons Why ENSO Does Not Have a Long-Term Impact on Climate Trends-------
1. ENSO is episodic
The first strike against ENSO having a long-term impact on climate trends is that ENSO events are temporary. El Nino’s typically last for 9 months to ~12 month. La Nina’s can last for 1 to 3 years. As ENSO events do not last long, a trend in a particular ENSO event becoming more common and more intense would have to exist in order for ENSO to have any chance* on influencing long-term climate trends (*as described further below (#6, 7 and 8 specifically), even if a trend did exist, this chance is extremely low).

2. ENSO is roughly cyclical
ENSO switches between a positive PDO phase, when El Nino events dominate, and a negative PDO phase, when La Nina events dominate. The duration of the phase varies but has a cycle of roughly 30 years. No long-term trend of more El Nino’s and less La Nina’s have been observed. So any short-term variable warming cause by the positive PDO phase is roughly balanced by the negative PDO phase. The opposite is also true.
[image link ]

3. ENSO has no notable long-term increase in the intensity of El Nino’s or La Nina’s
It’s possible that, even if cyclical, ENSO could still have an impact if the intensity of a particular ENSO event was increasing (i.e. stronger El Ninos = warming, colder La Ninas = cooling). However, there appears to be no notable long-term trend in the intensity of ENSO events in the recent past, let alone the intensity of a particular ENSO state. It might be said that Trenberth 2002 found that ENSO left a residual impact in the latter half of the 20th century (1950-1998)…of 0.06 deg C. Not per decade, total. Not only is this not significant, it’s also heavily biased by the referenced period. The 1950’s were dominated by La Nina (negative PDO) and the 1990’s where dominated by El Nino (positive PDO). What this 0.06 deg C value really means is that the impact from a negative PDO to a positive PDO is minimal. Addressing a negative PDO period to another negative PDO period would likely have even less of an impact.

Some research does suggest that model projections indicate that the intensity of ENSO events could possibly become stronger as a response to global warming. However, this merely states that the short-term internal variability could be stronger in the future, which is an expected result of global warming. So even if ENSO events become more intense as a result of global warming, it does not follow that they will have an impact on long-term trends.

4. ENSO has had no notable long-term impact on pre-industrial temperature trends
ENSO has been a natural occurrence long before the pre-industrial period. Removed from major anthropogenic CO2 influences, if ENSO had any long-term impacts on climate, they should be evident in paleotemperature reconstructions. However, global temperatures have been very consistent in the Holocene. There is no evidence of ENSO impacting long-term climate change during the Holocene.

5. ENSO is not a driver
As ENSO has had no notable impact on long-term climate in the past (recent or paleo), it is obviously not a driver of climate change. Nor could it ever. Drivers must be “external” to normal climate, such as solar activity, orbital variance, volcanoes, anthropogenic actions. ENSO is an inherent part of climate. Even if ENSO were to or could possibly change in the future, it wouldn’t do so magically on its own. It would be a feedback to another driver. A possible “change” in ENSO could be a destabilizing of ocean currents. This “tipping point” for climate is unlikely to occur outside a major, calamitous event (i.e. asteroid or super massive volcanoes).

(*I’ll point out that the fact that ENSO is not a driver, on its own, doesn’t mean that that it couldn’t impact long-term climate change (for that you’ll have to take all the other points into consideration). Of course feedbacks can have substantial long-term impacts on climate. However, this does display the myth that ENSO, and not CO2, is driving for long-term global warming.)

6. ENSO only causes surface temperature to temporarily deviate from the “average”. It doesn’t impact the “average”.
A key aspect of ENSO, often forgotten by people that believe ENSO has a long-term impact, is that the “heating” during El Nino years and “cooling” during La Nina years is relative to recent years. El Nino events will be hotter than “average”, La Nina events will be cooler. However, if, in the long-term, the “average” is warming or cooling, this will become more significant than the short-term internal variability of ENSO. And this is exactly what we see. The 1995 El Nino was cooler than all ENSO neutral years and even all La Nina years in the 21st century. The 1983 El Nino (the 2nd strongest El Nino ever) was cooler than all La Nina years since 1995. In the long-term, the signal dominates the noise.

Another way to look at this is to examine El Nino years against El Nino years, La Nina years against La Nina years and ENSO neutral years against ENSO neutral years. What you see is that, in the long-term, EL Nino years, La Nina years, ENSO neutral years and all of them combined have similar warming trends.
[image ]

This, to me, is some of the strongest evidence against ENSO having a notable long-term trend on our climate. It simple does not impact the “average”. It merely allows for a temporary deviation from it. So, even in the most absurdly optimistic condition (perpetual La Nina), you’d still have a warming planet and you’d still have an energy balance problem.

7. ENSO does not significantly impact the TOA radiative balance
The two main reasons why ENSO doesn’t impact the “average” is because it is episodic (as discussed in #1) and it does not significantly impact the TOA radiative balance. In order to have a notable impact on long-term climate, the driver or feedback must have a notable impact on the TOA radiative balance in the long-term. Anything else is merely internal variability caused by moving energy around the system – which is what ENSO is mainly about.

Note that I’m not saying that ENSO doesn’t impact TOA at all; it does very slightly impact the TOA radiative balance by affecting cloud cover temporarily. Mayer et al 2013 found that “TOA net radiation perturbations are small”. Trenberth et al 2010 states that “The main changes in SSTs throughout the tropics are associated with El Niño Southern Oscillation (ENSO) events in which the dominant changes in energy into an atmospheric column come from ocean heat exchange through evaporation, latent heat release in precipitation, and redistribution of that heat through atmospheric winds. These changes can be an order of magnitude larger than the net TOA radiation changes” (my emphasis).

If ENSO had a major impact on TOA, you’d expect to see it appear in Ocean Heat Content data. If La Nina’s cooled the earth by impacting TOA then you’d expect to see sharp drops in OHC during strong La Nina years that mimic the surface temperature. The opposite for El Nino years. However, this is not the case. OHC has steadily risen, even throughout the “pause”.
[image ]

The vast majority of the influence from ENSO events on surface temperatures comes from moving heat around the system, not impacting TOA balance. This is the result of the mechanism of ENSO, which is the moving of hot water to the surface during El Nino, where it interacts with the atmosphere more readily, and pooling it in the deep ocean during La Nina, where it can’t interact with the atmosphere as readily – i.e. temporarily releasing and storing heat. Meehl et al 2010 examined OHC during “hiatus” periods (negative PDO) and “non-hiatus” periods (positive PDO) and demonstrates that, in keeping with our understanding on ENSO, deep OHC increases faster during negative PDO phases (storing phase) but upper OHC increases faster during positive PDO phases (releasing phase). Balmaseda et al 2013 shows similar results.

Hoerling et al 2008 wraps things up nicely. They found that “Our results indicate that natural variations internal to the Earth's climate system have had a relatively small impact on the low frequency variations in global mean land temperature. It is therefore extremely unlikely that the recent trajectory of terrestrial warming can be overwhelmed (and become colder than normal) as a consequence of natural variability.”

8. ENSO has no inherent mechanism that could have a major impact on long-term trends
The reason why ENSO doesn’t have a notable impact on long-term trends is because it lacks a necessary mechanism to actually impact long-term trends. ENSO temporarily causes more heat to be stored in (La Nina) or released from (El Nino) the ocean. It does not have a major impact on adding or removing heat from the Earth (i.e. it doesn’t significantly impact TOA). I’ll use an analogy of a hydronic home heating system with a hot water tank for storage. The analogy, like all analogies, is not perfect. I have no doubt that “skeptics” will cherry pick this analogy to death yet it matters very little to the overall point. Hopefully it helps illustrate the mechanism of ENSO to some.

- The home represents Earth.
- The electric water heater represents the Sun.
- The room temperature represents the global surface temperature.
- The hot water tank represents the oceans
- The control valve on the outlet of the hot water tank represents ENSO
- Insulation on your house and around the tank walls represents green house gases

Unlike a normal electric water heater, but quite like the sun, this particular electric heater runs all the time, regardless of room temperature. This isn’t a big problem because the house had terrible insulation and so the heat input from the electric heater closely matched the heat loss through the walls. However, someone started putting insulation into the walls. Now the heat input from the heater is slightly greater than the heat loss through walls.

What’s worse, the control valve on the outlet of the boiler cannot be controlled. It’s normally at 50% open, which we’ll call “neutral” but, seemingly randomly, flips between being slightly more than 50% open, which we’ll call “opEN” state, to slightly less than 50% open, which we’ll called “cLNosed” state. Over the long-term, there’s no notable trend of the control valve being more in the opEN state than the cLNosed state. In the neutral state, the room heats at a fairly steady rate since the insulation has been added. When in the opEN state, more hot water goes to heat the room and the room heats faster but there is less hot water left in the tank. When in the cLNosed state, less water goes to heat the room and the room heats slower but there is more hot water left in the tank.

This past Monday there was a very strong opEN state but this Saturday and Sunday were very strong cLNosed state days, which meant there was an insignificant increase in room temperature for this week. However, the hot water tank temperature continued to rise throughout the week (and months), the room temperature for the past two month increased steadily (since the insulation was added) and more so this past month (when more insulation was added) than the first month, and the strongest opEN day last week was actually colder than the strongest cLNosed state this week.

It’s obvious that the control valve is not responsible for the warming. While the control valve can add considerable noise to the warming trend, it is not responsible for the warming trend. Even if, in the future, we could “fix” the valve to always be in the cLNosed state (which is analogous to some MAGICAL perpetual La Nina state), we still would not fix the problem. The hot water tank would continue to warm and so would the room. You would still have an energy balance problem where the heat input is exceeding the heat output, even if not all of that heat was going to the room (/atmosphere) but instead was building up in the tank (/oceans).

TL;DR
Q: Does ENSO have the ability to have a major impact on the long-term trend of global climate?
A: No.
 
looking at your graph of average annual temperature, some things jump out at me ...
1) no reference, you chide others for posting unreferenced material,
2) 1998 stands out as an exceptional year, and very unfortunately,
3) a linear trend line through that data is IMO mindlessly simplistic,
4) if 2014 is the hottest year on record (as I understand people say it was) it must look like the lamented 1998,
5) the trend line through the last 10 years looks awfully flat (did someone say "pause" ?).

another day in paradise, or is paradise one day closer ?
 
1) NASA
2) Hottest El Nino on the modern record.
3) The point is, if ENSO had some significant long-term influence, you wouldn't see long-term trends for El Nino years, La Nina years and all years match as closely. It demonstrates that the warming trend exists regardless of the ENSO state.
4) According to some temperature record sets it is most likely the hottest year on record. However, I still feel 2010 could be (mainly because Cowtan and Way still lists 2010 as the hottest). It matters little though. But yes, 2014 is much higher than 2013 and it was a ENSO neutral year.
5) Haha
 
(sorry #2 should read Strongest El Nino on the modern record)
 
Nice long copy paste. Long on assertion short on supporting evidence. I'm also left to wonder what is long term. You say that the ENSO is short term but then say that it's driven by the PDO which is a 60 year cycle. Drawing a long term trend is meaningless. The simple fact is that in your long term trend warming is only observed for 2 30ish year periods. 1911-1945 and 1976-2001 both in phase with the positive PDO given a slight lag.. Before you start throwing stuff to a wall and hoping it sticks you first have to set some solid definitions you seem to use a nebulous "short term" "long term" that has no meaning but what suits your argument.
 
P.S. Most of your argument is depend on reanalylsis of ocean heat content data which is totally unreliable.

Wunsch and Heimbach (2013) wrote, “clear warnings have appeared in the literature—that spurious trends and values are artifacts of changing observation systems (see, e.g., Elliott and Gaffen, 1991; Marshall et al., 2002; Thompson et al., 2008)—the reanalyses are rarely used appropriately, meaning with the recognition that they are subject to large errors

It's a fools errand to think that we know what ocean heat Co tent is over the term you claim.
 
This is all nice, but it does not hit the topic very well.
 
Okay lets start playing with rconnor

“If ENSO had a major impact on TOA, you’d expect to see it appear in Ocean Heat Content data. If La Nina’s cooled the earth by impacting TOA then you’d expect to see sharp drops in OHC during strong La Nina years that mimic the surface temperature. The opposite for El Nino years. However, this is not the case. OHC has steadily risen, even throughout the “pause”"

This understanding of la nina couldn’t be more wrong. The la nina phase of the ENSO is the ocean heating phase. During an el nino the pacific gives up energy and during a la nina it absorbs energy. Not only does that wind your previously mentioned start to pool energy it also blows away cloud cover letting more solar radiation reach the ocean surface. Remember we don’t care about the top of the atmosphere we care about how much short wave radiation is actually reaching the surface of the ocean. You would think that before making your argument you would make sure you aren’t violating the first law.
 
Link

Saw this the other day, thought it was interesting and more on topic. Obviously very early stages of research, so take what you will.
 
Given that the deep earth has a heat content higher than the surface, and volcanic activity is one of the ways that heat is slowly transfered to the surface. So this transfer, while not predictable should be within a range. From that the surface conditions should follow heat content added - heat content loss = change in heat content. What changes climate on the surface is losses, gains, transfers between solid, liquid, and gas, and changes of state.
So what is unpredictable? Heat transfer from the core, and energy from the local star, but both of these should be in a typical range, which over time should give a cone shaped range of possibilities.
It's not happening, and that is a red flag.

Changing reflection from the surface, or clouds, is a given, and should be predictable provided the inputs are correct. Is this being calculated correctly?
Are we adding that the surface is changing everytime we add a solar panel?
 
If the positive PDO is responsible for the warming period, and not some underlying warming trend, then the negative PDO phase should cool the planet, not merely cause warming rates to decrease slightly. In reality, we see periods of accelerated warming during positive PDO phases and modest warming during negative PDO phases – because there is an underlying warming trend.

If it’s a 60 year cycle and the positive PDO phase is responsible for the accelerated warming seen after 1970, and not some underlying warming trend, then 1949 should be approximately the same temperature as 2009 (originally I went 1950-2010 but didn’t want to pick the hottest year on record as the final date). Unfortunately, 2009 (a La Nina year, by the way) was 0.87 deg C warming than 1949 – because there is an underlying warming trend.

GTTofAK said:
Okay lets start playing with rconnor
Wow, this post is…ahh…interesting. You missed the point of the quote so badly that you actually reinforced exactly what I was trying to say. I’m going to repeat the quote, bold some things you missed and expand on some points (that should have been obvious).

rconnor said:
[***]If[***] ENSO had a major impact on TOA [which it doesn’t], you’d expect to see it appear in Ocean Heat Content data. [***]If[***] La Nina’s cooled the earth by impacting TOA [which it doesn’t] then you’d expect to see sharp drops in OHC during strong La Nina years that mimic the surface temperature. The opposite for El Nino years. However, this is not the case. OHC has steadily risen, even throughout the “pause”.

Point #7 demonstrates that ENSO does not significantly impact TOA. The quote above further proves that by demonstrating that if it did, you’d expect OHC to behave in a way that it hasn’t. Then you come along and hammer this point home by restating that ENSO doesn’t behave that way.

The funny thing is that post by you wasn’t wrong (…for the most part. Your comment that TOA radiative balance isn’t important is laughable). It matches what I said about how ENSO operates (I compared your quotes against some of mine below). ENSO does not significantly impact TOA. The majority of the influence of ENSO comes from moving heat around the system (which your post reinforces) – which is one of many reasons why ENSO does not have a major impact on long-term climate trends.

GTTofAK said:
During an el nino the pacific gives up energy and during a la nina it absorbs energy
rconnor (from #8) said:
ENSO temporarily causes more heat to be stored in (La Nina) or released from (El Nino) the ocean

GTTofAK said:
it also blows away cloud cover letting more solar radiation reach the ocean surface
rconnor (from #7) said:
Note that I’m not saying that ENSO doesn’t impact TOA at all; it does very slightly impact the TOA radiative balance by affecting cloud cover temporarily
 
Still none of the diagrams show a range, but a 100% known trejectory. Which is not possible to be 100% accuriate, so all the predictions that show a know trejectory are wrong.
If a range is not predictable then the model is wrong.

Bottom line is not if there is a change, but that we can't model it to say what action we should be taking.

What I do see is there is more veriability in weather, not that that indicates a direction in the baseline.
 
And there we have it: The standard "your data is meaningless" versus "No - YOUR data is meaningless" Eng-Tips climate debate.

Thanks for coming out...
 
Cranky, see below an image of the range of model runs and observed temperatures from AR5 (Figure 1.4):
[image ]

CELinOttawa, this is about the third time you’ve posted in a climate change thread that you’re not interested in climate change threads. If you’re not, I’d recommend not wasting your time reading and posting in climate change threads. Or if you want to try to bring forward the science as honestly as you can, in hopes that people will learn (i.e. are a masochist and enjoy banging your head against a very thick wall), then do so. But posts about your disinterest are a waste of time for others and, more importantly, yourself.
 
"If the positive PDO is responsible for the warming period, and not some underlying warming trend, then the negative PDO phase should cool the planet, not merely cause warming rates to decrease slightly. In reality, we see periods of accelerated warming during positive PDO phases and modest warming during negative PDO phases – because there is an underlying warming trend."

I agree that there is an underlying warming trend. Its the trend we have seen since exiting the little ice age. If we use the 1911-1945 natural warming as a control case there is no discernible difference from the 1976-2001 warming. However it is a fallacy to say that phases of the PDO average out to 0. The negative phase does not have to equal the positive phase. Thinking that it does is nothing but new age earth in perfect balance yin and yang hippy bull. Start talking like an engineer and not some aging boomer in a hot yoga class.

"Point #7 demonstrates that ENSO does not significantly impact TOA. The quote above further proves that by demonstrating that if it did, you’d expect OHC to behave in a way that it hasn’t. Then you come along and hammer this point home by restating that ENSO doesn’t behave that way."

Ah I see you are trying to ignore that you said what you said you did.

"If La Nina’s cooled the earth by impacting TOA then you’d expect to see sharp drops in OHC during strong La Nina years that mimic the surface temperature."

This represents a total lack of understanding on your part about the ENSO. Since you don’t understand it we can’t expect you to actually look for the right evidence.

“ENSO does not significantly impact TOA.”

It looks to me that during the current La Nina phase it has significantly affected the outgoing short wave radiation.

URL]


“The majority of the influence of ENSO comes from moving heat around the system (which your post reinforces) – which is one of many reasons why ENSO does not have a major impact on long-term climate trends.”

And there is the rub. You don’t define what long term is!!! The PDO determines the relative the strength of the ENSO. It’s a 60ish year cycle. That is very long term. We only have somewhat accurate ocean data starting at ARGO even then ARGO is limited. Any attempt to create something before ARGO with model reanalysis is a fool’s errand and will inevitably reflect the bias of the modeler and models. Reanalysis can in no way be confused with data and used to confirm models.
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor