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

[Maui]

These "small" volcanic eruptions are being viewed by some scientists as potentially having a greater influence on earth's climate than was previously believed:

http://www.rdmag.com/news/2015/01/s...?et_cid=4359172&et_rid=407330416&location=top

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

 

[IRstuff]

"What does a temperature trend look like over that 4.5 billion years of history"

We seriously lack temperature measurements or proxies going that far back. But, bear in mind that a trend starting that far back is a bit meaningless, given that the surface temperature was probably in excess of 5000ºC. We're NEVER going to get that hot, unless we collide with something humongous.

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[rb1957]

I understand that we do know it's been much hotter (and colder) in the past, that CO2 levels were much higher in the past (maybe there's some correlation ... maybe causal, maybe not). I understand we know there were sudden climate changes in the past, mechanism not well understood.

But this is, to a large extent, a red herring in the current debate. The current debate is how much is the FF we burnt yesterday affecting today's climate, that our reintroduction of CO2 back into the atmosphere is an unnatural (and unprecedented) process.

another day in paradise, or is paradise one day closer ?

 

[cranky108]

" FF we burnt yesterday" I can't keep from wondering why we burnt French Fries yesterday. I know what you mean, but FF dos not make me think of Fossel Fuels.

Present the data where we don't need to question the collector or method used. Not that easy. Maybe that's why no one believes the other argument. Or the conclusion that we do nothing, or heavy taxes, smaller cars, etc.

Don't get me wrong, the methane leaks fixing is a good thing (it's just a sign of bad behavior).

 

[rconnor]

KENAT, please see my post at 19 Mar 15 20:28 in this thread. I, and many others that believe mitigation is necessary, do not advocate for a cap-and-trade system. I think it’s important to not frame mitigation in such a one-dimensional fashion.

lacajun, that’s a good question. Someone asked something very similar in a previous thread. Please feel free to read my response at 23 Oct 14 17:19. You’ll note that my end conclusion is pretty much exactly the same as IRstuff’s response here (except I lack his brevity!).

rb1957,

we know there were sudden climate changes in the past

I think we need to be careful with some of the wording here. The “sudden” in your statement is on the order of thousands of years. Geologically speaking, this is indeed sudden. However, compared to the rate of change in the 20th-21st century, that’s moving at a glacial pace (…well given the rate of decline recently, this phrase may no longer be appropriate…but you catch my drift).

I understand we know there were sudden climate changes in the past, mechanism not well understood.

I disagree. The mechanism of past changes in climate is fairly well understood. It goes something like this (for deglaciation):
[ul 1][li]Orbital variations increase summer insolation at higher latitudes in the Northern Hemisphere (i.e. the North Pole points towards the sun more, see Richard Alley (comically) explain Milankovitch cycles (he’s a delightfully kooky guy)). This is fairly weak change in forcing but it leads to a series of climatic changes…[/li]
[li]The increase in Arctic and Northern Hemisphere summer insolation causes the rate and extent of ice sheet melt to increase[/li]
[li]North Atlantic deep water formation is inhibited by this freshwater runoff[/li]
[li]Thermohaline circulation is interrupted[/li]
[li]Northern Hemisphere actually cools as the equator to pole heat transports weakens[/li]
[li]Heat that use to transfer to the North, now works to warm Southern Hemisphere oceans[/li]
[li]Southern Hemisphere warming releases large reservoirs of CO2 from deep water[/li]
[li]Global CO2 concentrations increase which leads to global warming[/li]
[li]Global warming release CH4 feedback and positive ice albedo feedback[/li]
[li]Warming intensifies (note: this process takes thousands of years)[/li]
[li]As the initial driver (Milankovitch cycles) is not strengthening and as you run out of ice to melt (to provide a positive feedback), the climate settles momentarily before the opposite cycle kicks it[/li][/ul]

Some of this will sound familiar. The same underlying concepts explain past changes in climate as well as modern changes. The same (range of) sensitivity estimates explain past changes in climate as well as modern changes. The same cannot be said about any other theory I know of. This is why I’m very confused when people use “it’s change before” as an argument against anthropogenic climate change. I will also note that the 20th century warming could not be due to Milankovitch cycles because (1) the rate of deglaciation caused by Milankovitch cycles occurs over thousands of years (as stated above) and (2) the timing is all wrong (it’s off by about 20,000 to 50,000 years). But I digress…

But this is, to a large extent, a red herring in the current debate.

How so? It’s the same planet. You need a theory that explains past and current changes in climate. The mechanism can’t magically change (however, you do need them to magically change to make “competing” theories fit). Furthermore, the impacts of paleoclimate on biodiversity are extremely relevant. Major extinctions correspond to past (major) changes in climate (which is another reason I’m confused why the “it won’t be bad” crowd seem to also be a part of the “it’s changed before” crowd (which are part of the “it’s not caused by CO2” crowd)).

The current debate is how much is the FF we burnt yesterday affecting today's climate

If you’re questioning how quickly CO2 emissions impact the climate, I responded to this at 13 Mar 15 19:37.

If you’re questioning the extent to which CO2 emissions will impact climate (now and into the future), i.e. climate sensitivity, than, yes, I agree this is where the current debate lies. A great conference was just held on the subject of sensitivity. A lot of great information can be found at the Max-Planck Institute of Meterology.

However, I’ll point out again, that this is absolutely related to paleoclimatology. For example, if you want to say, “climate sensitivity (ECS) is likely about 1K. Therefore, future temperatures won’t be that high.”, you not only have to demonstrate how that value would be consistent with 20th century warming but, also and equally importantly, how it would explain past changes in climate. Beyond that, you’ll also need to explain how a low sensitivity planet lead to past mass extinctions. From what I’ve seen, you need an ECS of >2K to explain all this.

Perhaps I’m misinterpreting what you meant by it being a “red herring”, but paleoclimatology is absolutely relevant and extremely important to the current climate change debate. I hope we agree on that.

 

[GTTofAK]

I think we need to be careful with some of the wording here. The “sudden” in your statement is on the order of thousands of years.

Not true at all. Ice cores are the best proxy we have for global climate shows rapid changes in global temperature during the Holocene.

Your claim that such changes only happen on the order of thousands of years is not supported by the evidence.

You are focusing on the poor proxy resolution in the distant past and assuming that such small decadal changes didn’t happen because we cant see them. But we know from earlier ice cores that such changes are quite common but we only have resolution to see them in the Holocene past that the ice is too compressed.

You seem to live and breathe in this lack of data environment where absence of evidence is evidence of absence. We know that rapid changes occurred in the Holocene ice core resolution therefore it is safe to assume that such rapid changes occurred earlier in the record. We however lack the resolution to see them but that does not mean that they did not happen.

I disagree. The mechanism of past changes in climate is fairly well understood. It goes something like this (for deglaciation):

Such an absolutist statement, much of your following claim is pure speculation.

1. Orbital variations increase summer insolation at higher latitudes in the Northern Hemisphere (i.e. the North Pole points towards the sun more, see Richard Alley (comically) explain Milankovitch cycles (he’s a delightfully kooky guy)). This is fairly weak change in forcing but it leads to a series of climatic changes…

This is the only solid evidence based part of your post. I hope everyone notices that it’s the only part that rconnor actually supported. The reason for this is it’s the only party that is supportable with hard evidence.

After this small truth rconnor goes off into pure speculation hoping that the initial truth will trick people into thinking that the following speculation is just as supported fact. This is a classic propaganda technique and has no place in science.

2.The increase in Arctic and Northern Hemisphere summer insolation causes the rate and extent of ice sheet melt to increase
3. North Atlantic deep water formation is inhibited by this freshwater runoff
4. Thermohaline circulation is interrupted
5. Northern Hemisphere actually cools as the equator to pole heat transports weakens
6. Heat that use to transfer to the North, now works to warm Southern Hemisphere oceans
7. Southern Hemisphere warming releases large reservoirs of CO2 from deep water
8. Global CO2 concentrations increase which leads to global warming
9. Global warming release CH4 feedback and positive ice albedo feedback
10. Warming intensifies (note: this process takes thousands of years)
As the initial driver (Milankovitch cycles) is not strengthening and as you run out of ice to melt (to provide a positive feedback), the climate settles momentarily before the opposite cycle kicks it

Nice hypothesis, but its hardly a “fairly well understood” truth. It fits nicely with AGW but there is no evidence to support it and actually rather convincing evidence to refute it. I know that in alarmists circles this is taken as gospel but there is harldy any evidence to support it. Its pure speculation. If you believe that CO2 can drive warming of the atmosphere then this hypothesis makes sense and is true to you. But other than your absolute belief in AGW this hypothesis is an unsupported hypothesis. We need only look at the relationship between CO2 and temperature found in ice cores to see that your hypothesis holds no water.

Study it carefully. We can see that temperature actually follows inslolation not CO2. No look very closely. Your unprovable hypothesis is that early small warming leads to CO2 which drives the remainder of the warming. Look at the rest of the graph. There are multiple small peaks with CO2 jumps but no maintained warming. The atmosphere never runs away. There is no positive feedback or there would be multiple peaks not just 2. Your hypothesis is incorrect and largely circular.

You believe that CO2 drove the warming then because you believe that CO2 is driving the warming now. You believe that CO2 is driving the warming now because CO2 drove the warming then.

In the end the evidence you have is really your own self-reinforcing belief. We get it you believe strongly in AGW. But your quasi-religious belief is not evidence.

How so? It’s the same planet. You need a theory that explains past and current changes in climate. The mechanism can’t magically change (however, you do need them to magically change to make “competing” theories fit).

Let the logical fallacies begin, onus probandi, shifting the burden, argumentum ad ignorantiam, argument from ignorance, fallacy of a single cause. You watched too many Perry Mason shows as a kid. There is no logical requirement to offer a competing theory. The onus is on you to prove your theory not for someone else to prove another. Furthermore you don’t need one theory, fallacy of a single cause.

 

[GTTofAK]

Cont


Again your belief that you do is just reinforced personal bias. You believe that AGW is the driver of global climate and is therefore the cause of all climate change. The evidence for your claim is your own belief.

Furthermore, the impacts of paleoclimate on biodiversity are extremely relevant. Major extinctions correspond to past (major) changes in climate (which is another reason I’m confused why the “it won’t be bad” crowd seem to also be a part of the “it’s changed before” crowd (which are part of the “it’s not caused by CO2” crowd)).

But as evidenced by the record the major extinctions are associated with rapid cooling not warming. Life booms during a warming. If anything AGW would maintain the warming we are enjoying longer and stave off the catastrophe that is associated with sudden cooling, they don’t call it the dark ages for nothing you know.

However, I’ll point out again, that this is absolutely related to paleoclimatology. For example, if you want to say, “climate sensitivity (ECS) is likely about 1K. Therefore, future temperatures won’t be that high.”, you not only have to demonstrate how that value would be consistent with 20th century warming but, also and equally importantly, how it would explain past changes in climate. Beyond that, you’ll also need to explain how a low sensitivity planet lead to past mass extinctions. From what I’ve seen, you need an ECS of >2K to explain all this.

Perhaps I’m misinterpreting what you meant by it being a “red herring”, but paleoclimatology is absolutely relevant and extremely important to the current climate change debate. I hope we agree on that.

Same fallacies used above. The onus is on you to prove your theory not require others to prove an alternative. You cannot begin at CO2 caused mass extinctions prove another reason. There are actually many competing theories about various mass extinctions. Your its all CO2 hypothethisis being a relative new comer backed more the religious fervor you display here rather than actual evidence.

 

[rconnor]

lacajun, sorry, I only partially answered your question. With regards to "What do GHG trends look like over that same span of time?" we can look at NOAA data from ice cores:

Of course the dating and exact values are only roughly accurate but it certainly illustrates a correlation between the two. A key question often asked is "so does CO2 lead or lag temperature?". The best science we have tells us the answer is both. This plays into your next question, "What drivers can be unquestionably identified for those trends?" (although, I think we need to replace "unquestionably identified" with "identified with the highest probability").

The natural CO2 cycle keeps atmospheric CO2 relatively constant. However, it doesn’t stay constant for very long (on geological scales). Disruptions to the natural CO2 cycle cause concentrations to increase or decrease. A common driver is Milankovitch cycles or massive geological events which cause an initial change in temperature which leads to changes in CO2 concentrations (see above for a bit more detail or Alley 2000). In this way, CO2 lags temperature.

However, the change in Arctic insolation from Milankovitch cycles is too weak to account for all warming seen. Despite the drivers initiating the change, it's the feedbacks (GHG, albedo, etc.) that are responsible for the majority of the change. CO2 increases the greenhouse effect and causes temperature to rise and therefore acts as a positive (warming) feedback. Not only does CO2 correlate well with temperature change but it causally explains the extent of the temperature change. The increase in temperature from increased CO2 leads to further feedbacks which increase the temperature even more (again, see above for some more details). In this way, CO2 leads temperature.

In the modern context, climate change does not correlate to Milankovitch cycles, solar activity or other geological events. It does, however, correlate with increases in anthropogenic CO2 emissions. Applying the same principals and understanding from paleoclimatology, we get a very consistent picture. Increased levels of CO2 are increasing global temperatures. The increase in global temperature will have feedbacks (positive/warming and negative/cooling). Paleoclimate tells us that even with a weak initial driver, the earth’s climate sensitivity is high. Today, we have a moderately strong initial driver – anthropogenic CO2 emissions. As indicated by paleoclimate, even if we stop CO2 emissions today, the slow feedbacks will continue to warm the planet for decades or centuries.

As stated, the statement “it’s changed before” is actually an argument for the anthropogenic climate change theory, not against. “It’s changed before” tells us:
[ul 1][li] The earth’s climate sensitivity is high (or at least non-negligible),[/li]
[li]CO2 concentrations, while not always the driver, play an important role in the Earth’s temperature, and[/li]
[li]Changes in global temperature lead to drastic changes in biology, usually involving mass extinctions.[/li][/ul]

So, you’ve brought up many important questions that are central to climate science. Thank you for bringing them up. Understanding paleoclimate (or how “it’s changed before”) is essential to understanding modern climate change.

(Amidst honest efforts to ask questions and explain the science, we have some attempts to use misinformation to muddy the waters. Such is the case with these discussions. For anyone new, I’m not bothering with such comments. However, if you’re curious about the validity of the points made about GISP2, see this response by Richard Alley. I’ll note that Richard Alley is one of the primary scientists responsible for GISP2 data. It would seem he’d have a pretty good grasp on what it actually shows. Using the absolute measurement of a single record says nothing about global temperatures (ex. follow the absolute temperature of your home town and see how it maps to global averages). Beyond that, even if the data were relevant to global temperatures, the image incorrectly assume “present” in the GISP2 data is 2000, it’s not. It’s 1950. The first data point in GISP2 is 95 years before “present”, so 1855. The image, therefore, ignores the last 150 years of warming. This is the trouble that comes from taking some random bloggers opinion on the data rather than the climate scientists in charge of the data’s take on it. The remainder of the post just gets worse.)

 

[lacajun]

rconnor, I will investigate some of your sources.

Yellowstone's big magma layer

Pamela K. Quillin, P.E.
Quillin Engineering, LLC

 

[GTTofAK]

What sources? His onlysubstantive point is that Milankovitch cycles aline aren't enough . Which 8s sourced with a blanket link to a genetic NCDC page. He then runs off j to a lot of speculation about positive CO2 feedback filling in the difference. He has no evidence to support this. It's pure speculation there is no evidence to prove itwhile there is some to refute ir. There are plenty of incidences in the record of a substantial CO2 rise but no positive feedback.

You have to learn with rconnor'ss posts there is a lot of eyewash but the supporting evidence for his underlying claim is always weak. His sources are to tangential points I'm order to fool the reader into thinking that his underlying thesis is more supported than it actually is.

His thesis in this case 8s s positive CO2 feedback driving the warming. He supports this with absolutely nothing. The evidence isn't there. Nor will it ever exist. If he were to provide a source it would just be more speculation from some academic and/oor a model.

 

[lacajun]

GTTofAK, I understand from whence you write. I also try to understand from whence rconnor writes. As an engineer, albeit an old and outdated one, I am quite capable of independent thought still. However, some closest to me would probably debate that point and have me in hospice or the dementia ward. As an EE, too, I understand and still remember leading and lagging concepts from inductors and capacitors.

rconnor posted links and those are the sources I referenced. If they do not lead to peer reviewed papers by reputable, qualified people, it is up to me to determine my thoughts.

I know what I think. I am curious, to a minor degree, about the thoughts of both sides and what drives them. It is interesting to me, as a woman that has spent most of my life traveling to the Gulf of Mexico. My uncle had a front row beach house on Holly Beach and I have memories watching the rigs' lights appear and disappear with the rolling waves at night. I've seen other coastlines, too. At 55, my thoughts are, in part, shaped by those experiences. As a kid, the tide came in under the house and, further, crossed the road behind it quite often. The only thing that changed how far the tide came in were cement breaks along the coastline. I had not seen the waterline so far out and the tide remain so far out.

FYI, I am skeptical of man caused global warming and the catastrophes awaiting civilization for many reasons. But that does not stem curiosity nor should it, in my mind. I do not want to be smug and closed off to others and what they think and why, for the most part. Boundaries are sometimes needed.

Pamela K. Quillin, P.E.
Quillin Engineering, LLC

 

[cranky108]

Lacajun, I agree with your perspective, and I can see if even if carbon dioxide is not a problem now, that it can potentially become one.

To this end I have asked many times for options other than the media hyped taxes, public transportation, solar power, ect. I don't get much for answers.

I just don't get why the only answers we see appear to be some of the most disruptive technology. That we must destroy what we have to make improvments.

But from the lack of other options, I am concluding this not real. That the solutions being brought forth are political in nature, and make someone money.
This is in addition to the fact that those who are pushing this are also the same ones not following there recommendations.

 

[rconnor]

lacajun, I really enjoyed that post. Many great points that are so refreshing to hear. That is a great attitude, not just for the climate change debate, but life in general. It's true skepticism, which I mean in the most complimentary way.

 

[IRstuff]

"I just don't get why the only answers we see appear to be some of the most disruptive technology. That we must destroy what we have to make improvments. "

Really? I think the answer should be pretty clear; the low hanging fruit are usually already harvested, or overcome. Had we not been arguing about this for the last several decades, there might have be non-disruptive solutions and a gradual phasing away from the problem children. But, those on the other side have either blown it off, or gone out their way to make our dependence on carbon-based approaches even stronger. The current low oil prices and gas boom makes it even less likely that we switch away, so at the tipping point, assuming that's still in the future, we're going to have to go cold turkey, because all the gradual, phased solutions will not produce results fast enough or drastic enough. At some point in the past, solar and wind power could potentially have gotten farther, but the ROI was simply not there, and for a financially driven environment, that meant building more and expanding coal and gas generation facilities.

This is very analogous to the seat belt situation. Seat belts had been in existence for 50 years, but until a federal law made it a crime to not wear a seat belt, a large percentage of people wouldn't. So, yes we had disruptively create a crime to get the benefits of seat belt protection.

TTFN
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