Testing the Core of AGW Theory

[skierinvermont]

The oceans have massive depths with no temperature sensors in them. We only have a historical records of SSTs. We can see how much heat is being stored/released near the surface, but that is it. So while the ocean may be absorbing heat/energy at a fairly linear rate overall, the amount that is released at the surface is determined largely by ENSO fluctuations. Which is ENSO plays a big role in surface temperatures, and since ENSO is closely related to PDO phases, over the course of decades a +PDO phase will release a lot more heat into the atmosphere than a -PDO phase.

All energy entering and leaving the ocean must pass through the surface. AGW doesn't magically cause the deep ocean to warm while the surface of the ocean releases heat.

The ocean absorbed huge quantities of heat 1970-present.. and it lost energy 1950-1970... exactly the opposite of what you expect from the PDO.Nina hypothesis you have given.

The surface of the ocean was releasing energy to the atmosphere during the last -PDO which would have acted to warm the atmosphere not cool it.

The ocean and atmosphere cooled simultaneously 1950-1970. The ONLY way this can happen is if the cooling is EXTERNALLY forced.

[tacoman25]

All energy entering and leaving the ocean must pass through the surface. AGW doesn't magically cause the deep ocean to warm while the surface of the ocean releases heat.

The ocean absorbed huge quantities of heat 1970-present.. and it lost energy 1950-1970... exactly the opposite of what you expect from the PDO.Nina hypothesis you have given.

The surface of the ocean was releasing energy to the atmosphere during the last -PDO which would have acted to warm the atmosphere not cool it.

The ocean and atmosphere cooled simultaneously 1950-1970. The ONLY way this can happen is if the cooling is EXTERNALLY forced.

Actually, it really isn't understood how the deep ocean functions with energy storage/displacement. Again, all we are measuring is water temperature at or fairly near the surface. That is how you are defining the ocean temperatures of the PDO phases. It is very possible that -ENSO pushes down heat deeper into the ocean, while +ENSO brings it to the surface. We just know so little about how the ocean cycles function.

There was no "external" forcing from 1950-70 that should have been strong enought to have caused the earth to cool and overwhelm AGW forcing.

[skierinvermont]

There was no "external" forcing from 1950-70 that should have been strong enought to have caused the earth to cool and overwhelm AGW forcing.

Yes there was. Net forcing decreased. I've already posted this graph. You're clearly not processing the information being provided.

[WeatherRusty]

Can we see the effect of PDO oscillating about the underlying trend here?

[The_Global_Warmer]

Can we see the effect of PDO oscillating about the underlying trend here?

Isn't that telling...

[tacoman25]

Yes there was. Net forcing decreased. I've already posted this graph. You're clearly not processing the information being provided.

If you actually were to make linear trends lines for both of those, you would see that temperature outpaced "net forcing" during +PDO phases. The PDO phase/temperature correlation is better.

[tacoman25]

Can we see the effect of PDO oscillating about the underlying trend here?

Yes, we can. The PDO phases go up and down over multi-decadal periods, while the forcing upwards from AGW is constant (and increasing over time). The rate of temperature change is clearly affected by the PDO phase.

[skierinvermont]

If you actually were to make linear trends lines for both of those, you would see that temperature outpaced "net forcing" during +PDO phases. The PDO phase/temperature correlation is better.

I don't see it at all.. sorry.. you'll have to be more specific about what portion of the graph you are referring to. Temperature has correlated perfectly with net forcing... net forcing decreased 1945-1970.. you said it increased.

[tacoman25]

I don't see it at all.. sorry.. you'll have to be more specific about what portion of the graph you are referring to. Temperature has correlated perfectly with net forcing... net forcing decreased 1945-1970.. you said it increased.

1. Look at 1925-45. +PDO phase. If you were to make a linear trend of temperature increase during that period and compare it to the linear trend of net forcing, you would see the temperature trend is steeper.

2. Do the same for 1976-end of graph. Remember that those two huge volcanos effect the net forcing trend downward. The temperature trend is steeper overall than the net forcing trend.

I don't know how exactly "net forcing" is calculated, but the relationship is not as clear as the PDO phase one. The chance that temperatures would just happen to rise faster 1925-45 during +PDO phase and then suddenly flatten starting in the late 1940s right after the -PDO phase set in, and then begin to rise rapidly again in the late 1970s when the +PDO phase began again...it's highly unlikely to be coincidence.

[The_Global_Warmer]

So basically the PDO and AMO show correlation, while the underlying major trend upwards is pretty much attributed to AGW.

that was relatively easy to conclude and is pretty clear based on the data we have.

not that I am dismissing the sun and what not...I am sure that is calculated in net forcing.

[WeatherRusty]

Yes, we can. The PDO phases go up and down over multi-decadal periods, while the forcing upwards from AGW is constant (and increasing over time). The rate of temperature change is clearly affected by the PDO phase.

I'd say by eyeballing the graphic I posted that you have made a fair assessment. I'd also say the rate of change is affected by many things including solar variability. However, what we are concerned with is the underlying trend which over time tends to smooth out the overlying variation about the mean.

What we could say is that current temps are about 0.2C higher than they would otherwise be in the absence of PDO, ENSO, solar variability etc. and whatever else may apply. That still leaves 0.7C of warming since 1900 on the linear trend line alone.

[tacoman25]

I'd say by eyeballing the graphic I posted that you have made a fair assessment. I'd also say the rate of change is affected by many things including solar variability. However, what we are concerned with is the underlying trend which over time tends to smooth out the overlying variation about the mean.

What we could say is that current temps are about 0.2C higher than they would otherwise be in the absence of PDO, ENSO, solar variability etc. and whatever else may apply. That still leaves 0.7C of warming since 1900 on the linear trend line alone.

Right, I agree that over 100 years the PDO oscillations are not going to effect the overall temperature trend. The reason the PDO was originally brought up is that skiier said the warming over the latter half of the 20th century was accurately predicted by AGW science. However, I don't see how this could be the case, since science had no clue about natural cycles like the PDO and their effect on surface temperature until recently. And the PDO trend from 1950-2000 clearly favored warming.

[tacoman25]

I should also add that there has been a history of poor understanding of the relationships between AGW, ENSO, and temperature fluctuations. The common assumption in climate science for awhile was that AGW would probably produce more El Ninos, and that it seemed to be doing so (this assumption started before the PDO phases were well known).

Even now if you look up El Nino in Wikipedia, it says:

During the last several decades the number of El Niño events increased, and the number of La Niña events decreased.^[52] The question is whether this is a random fluctuation or a normal instance of variation for that phenomenon or the result of global climate changes toward global warming.

The studies of historical data show that the recent El Niño variation is most likely linked to global warming. For example, one of the most recent results is that, even after subtracting the positive influence of decadal variation, shown to be possibly present in the ENSO trend,^[53] the amplitude of the ENSO variability in the observed data still increases, by as much as 60% in the last 50 years.

However, this assessment is rapidly falling apart, as -ENSO has become more dominant as the new -PDO phase has set in. We are looking at the fourth -ENSO winter in five years now.

[skierinvermont]

1. Look at 1925-45. +PDO phase. If you were to make a linear trend of temperature increase during that period and compare it to the linear trend of net forcing, you would see the temperature trend is steeper.

2. Do the same for 1976-end of graph. Remember that those two huge volcanos effect the net forcing trend downward. The temperature trend is steeper overall than the net forcing trend.

I don't know how exactly "net forcing" is calculated, but the relationship is not as clear as the PDO phase one. The chance that temperatures would just happen to rise faster 1925-45 during +PDO phase and then suddenly flatten starting in the late 1940s right after the -PDO phase set in, and then begin to rise rapidly again in the late 1970s when the +PDO phase began again...it's highly unlikely to be coincidence.

Net forcing isn't about trends. For example, take 1976-present... the trend is effected by everything that occurs between 1976 and present. But what is most important to temperature is net forcing today. The fact that Pinatubo occurred in 1991 has nearly no effect on current temperature. Current temperature is determined by net forcing today. It takes some time to reach equilibrium of course, and that becomes a bigger issue the faster net forcing rises.

Which may be why temperature appears to rise more than net forcing did 1925-1945... but that also may be because the time lag was less back then than it is now. Today, even if net forcing stopped rising, temperatures would keep rising for a while longer. That probably wasn't as true back in 1945.

In fact, one might even expect that the relationship between net forcing and temperature break down as we progress into the 21st century. Net forcing is going to be rising too fast for surface temperature to keep up. That's true to a lesser extent today.. and an even lesser extent in 1945. Which may be why surface temperature responded so rapidly to the initial increase in radiative forcing.

On the other hand, our reconstructions of radiative forcing aren't perfect. So it is probably silly to get into little details like this. However, I see little reason to conclude that temperature is out of sink with radiative forcing.

Radiative forcing increased 1915-1945.. so did temperature... radiative forcing decreased 1945-1970.. so did temperature... radiative forcing skyrocketed 1970-present... so did temperature. I see little reason to introduce the PDO into this. That being said, I could still see it having a small effect of .05C or so.

The large majority of warming post 1970 however is clearly Anthropogenic. Only AGW predicted it and only AGW can accurately hind-cast it.

[tacoman25]

Radiative forcing increased 1915-1945.. so did temperature... radiative forcing decreased 1945-1970.. so did temperature... radiative forcing skyrocketed 1970-present... so did temperature. I see little reason to introduce the PDO into this. That being said, I could still see it having a small effect of .05C or so.

The large majority of warming post 1970 however is clearly Anthropogenic. Only AGW predicted it and only AGW can accurately hind-cast it.

How did radiative forcing decrease from 1945-70? CO2 was rising that entire period, and solar increased.

Why would temperatures suddenly start rising rapidly in the late 1970s shortly after the PDO flipped phases? You still haven't provided a good reason to ignore the obvious correlations between PDO phases and temperature trends the past 75+ years. And since we know that -PDO and -ENSO are related, and we know that -ENSO causes cooler surface temperatures while +ENSO causes warmer surface temperatures, why would you deny that periods with predominantly one type of ENSO would cause more/less surface warming over those periods?

1. +PDO phases have more +ENSO

2. +ENSO releases more heat into the atmosphere

3. This causes surface temperatures to warm

4. More +ENSO events over a 30 year period would cause that period to be noticably warmer than a 30 year period dominated by -ENSO events, regardless of AGW.

1970-2000 would have seen a significant warming trend without AGW. Because it went from -PDO to +PDO phases. Just as there was a signficant warming trend from 1920-40 without near as much GHG forcing as was seen the second half of the 20th century.

[skierinvermont]

How did radiative forcing decrease from 1945-70? CO2 was rising that entire period, and solar increased.

Why would temperatures suddenly start rising rapidly in the late 1970s shortly after the PDO flipped phases? You still haven't provided a good reason to ignore the obvious correlations between PDO phases and temperature trends the past 75+ years. And since we know that -PDO and -ENSO are related, and we know that -ENSO causes cooler surface temperatures while +ENSO causes warmer surface temperatures, why would you deny that periods with predominantly one type of ENSO would cause more/less surface warming over those periods?

1. +PDO phases have more +ENSO

2. +ENSO releases more heat into the atmosphere

3. This causes surface temperatures to warm

4. More +ENSO events over a 30 year period would cause that period to be noticably warmer than a 30 year period dominated by -ENSO events, regardless of AGW.

1970-2000 would have seen a significant warming trend without AGW. Because it went from -PDO to +PDO phases. Just as there was a signficant warming trend from 1920-40 without near as much GHG forcing as was seen the second half of the 20th century.

Solar did not increase 1945-1970.. it decreased. GHGs were decreasing much slower than they are today. And aerosol concentrations rose. Also a big volcano in the late 60s.

As I keep saying the PDO probably had some effect... but the warming post 1970 is predominantly anthropogenic.

[tacoman25]

Solar did not increase 1945-1970.. it decreased. GHGs were decreasing much slower than they are today. And aerosol concentrations rose. Also a big volcano in the late 60s.

As I keep saying the PDO probably had some effect... but the warming post 1970 is predominantly anthropogenic.

1. The biggest solar cycle on record occurred in the late 1950s.

2. Aerosol concentrations rose, but they didn't see a sharp jump in the late 1940s that would suddenly cause temperatures to cool. That was caused by a period dominated by -ENSO (-PDO). 1949, 1950, 1951, 1954, 1955, 1956 were all -ENSO years, with only one weak El Nino thrown in there. And -ENSO continued to dominate until the mid 1970s.

3. You said before that volcanos aren't significant to overall forcing (in reference to Pinatubo in the 1990s) trends.

[WeatherRusty]

How did radiative forcing decrease from 1945-70? CO2 was rising that entire period, and solar increased.

Why would temperatures suddenly start rising rapidly in the late 1970s shortly after the PDO flipped phases? You still haven't provided a good reason to ignore the obvious correlations between PDO phases and temperature trends the past 75+ years. And since we know that -PDO and -ENSO are related, and we know that -ENSO causes cooler surface temperatures while +ENSO causes warmer surface temperatures, why would you deny that periods with predominantly one type of ENSO would cause more/less surface warming over those periods?

1. +PDO phases have more +ENSO

2. +ENSO releases more heat into the atmosphere

3. This causes surface temperatures to warm

4. More +ENSO events over a 30 year period would cause that period to be noticably warmer than a 30 year period dominated by -ENSO events, regardless of AGW.

1970-2000 would have seen a significant warming trend without AGW. Because it went from -PDO to +PDO phases. Just as there was a signficant warming trend from 1920-40 without near as much GHG forcing as was seen the second half of the 20th century.

Yes, but again how much warming absent AGW? I would put the upper limit at about 0.2C based on the fluctuations about the averaged trend line. That would be 0.2C above and then 0.2C below and so on.

[tacoman25]

Yes, but again how much warming absent AGW? I would put the upper limit at about 0.2C based on the fluctuations about the averaged trend line. That would be 0.2C above and then 0.2C below and so on.

Hard to say, but that could be a fair estimate. In which case, the warming trend from 1970-2000 was probably about 50/50 or 60/40, AGW/natural.

[ORH_wxman]

OHC hasn't risen nearly enough to explain the flat lining of global temps in recent years. That is the biggest problem right now. It may just be a 10 year blip, but that is getting pretty long. OHC should keep rising...even more quickly.

[gracetoyou]

OHC hasn't risen nearly enough to explain the flat lining of global temps in recent years. That is the biggest problem right now. It may just be a 10 year blip, but that is getting pretty long. OHC should keep rising...even more quickly.

This is the issue! It's really, really hard to get away from the fact that PDO/AMO cycles have huge impacts on our climate...there's no debate, the proof is in the pudding. PDO looks to be the bigger player & AMO seems to only suppress or enhance PDO cycle affects. I don't have time to do this right now but look at how significant heating or cooling is when PDO/AMO are both in the - or +cycles at the same time. PDO effect is enhanced. Check out mid 1930's when both were +, early 1970's when both were -, and the later half of the 1990's were both + which also coincided with a record el nino. Global temps responded. As you know we have now entered -PDO for sure, but I would argue the turn started in 1999-2000 & that is the reason for the flat-lining in global temps (look at graph, it can be argued). When AMO turns - during the -PDO cycle it will enhance the PDO effect & global temps will decline.

I'm certainly not saying that human emissions cannot be a player on enhancing or suppressing the positive & negative phases of PDO but it would be nice just to hear some objective AGW representative to admit that natural variation is still a player & you can't blame every artic sea melt, extreme weather, etc. on AGW. It can certainly play a role, or at least I think it can, but which is the bigger player natural variation or AGW remains to be seen. Right now it looks from a non-expert that natural variation is the bigger player right now...Maybe in the future AGW might be. I don't think anyone knows right now.

[skierinvermont]

1. The biggest solar cycle on record occurred in the late 1950s.

2. Aerosol concentrations rose, but they didn't see a sharp jump in the late 1940s that would suddenly cause temperatures to cool. That was caused by a period dominated by -ENSO (-PDO). 1949, 1950, 1951, 1954, 1955, 1956 were all -ENSO years, with only one weak El Nino thrown in there. And -ENSO continued to dominate until the mid 1970s.

3. You said before that volcanos aren't significant to overall forcing (in reference to Pinatubo in the 1990s) trends.

1. Yes but the 60s saw the weakest cycle in the last 100 years.

2. Yes I agree the sharp drop around 1945 was due to the switch from several Nino years to a string of Nina years. But that doesn't explain why both the surface and oceans continued to show little warming in the late 50s and 60s. Only externally forced cooling could cause that.

3. I did not say that. Of course volcanoes have net negative forcing.. I never said anything remotely contrary. What I said was that the abrupt drop in forcing in 1991 has essentially no effect on temperatures after 2000.

[skierinvermont]

OHC hasn't risen nearly enough to explain the flat lining of global temps in recent years. That is the biggest problem right now. It may just be a 10 year blip, but that is getting pretty long. OHC should keep rising...even more quickly.

Our detection system is not good enough to support this. Plus the 0-2000m OHC construction from Schuckmann shows the expected rate of OHC increase (with considerable error bars). The slowing is only evident in the more limited 0-700m OHC.

The fact that sea level rise has continued at ~2.9mm/yr since 1998 and 2.3mm/yr since 2002, both greater than the 50-yr trend of 1.8mm/yr, is a pretty good indicator that OHC is rising at a similar rate and probably faster rate than it has for the last 50 years.

[tacoman25]

OHC hasn't risen nearly enough to explain the flat lining of global temps in recent years. That is the biggest problem right now. It may just be a 10 year blip, but that is getting pretty long. OHC should keep rising...even more quickly.

Well again, this is based on the assumption that OHC is an accurate and complete measurement of how much heat/energy is being stored in the ocean...

[tacoman25]

1. Yes but the 60s saw the weakest cycle in the last 100 years.

2. Yes I agree the sharp drop around 1945 was due to the switch from several Nino years to a string of Nina years. But that doesn't explain why both the surface and oceans continued to show little warming in the late 50s and 60s. Only externally forced cooling could cause that.

3. I did not say that. Of course volcanoes have net negative forcing.. I never said anything remotely contrary. What I said was that the abrupt drop in forcing in 1991 has essentially no effect on temperatures after 2000.

You just said that our detection system now isn't good enough to know the exact OHC trend. How do you know that during that -PDO/-ENSO period in the 50s and 60s, the ocean wasn't storing heat that we weren't detecting, well below the surface? We just don't understand oceanic circulations enough to make definitive statements like that.

[ORH_wxman]

Our detection system is not good enough to support this. Plus the 0-2000m OHC construction from Schuckmann shows the expected rate of OHC increase (with considerable error bars). The slowing is only evident in the more limited 0-700m OHC.

The fact that sea level rise has continued at ~2.9mm/yr since 1998 and 2.3mm/yr since 2002, both greater than the 50-yr trend of 1.8mm/yr, is a pretty good indicator that OHC is rising at a similar rate and probably faster rate than it has for the last 50 years.

If OHC is being stored deeper than previously thought, then climate models need to be readjusted for temperature change in the next century.

[tacoman25]

If OHC is being stored deeper than previously thought, then climate models need to be readjusted for temperature change in the next century.

Absolutely. This is something that is so overlooked in the AGW debate. We know the composition of the atmosphere, we know how much energy it is receiving approximately and how much it is retaining/losing (though there is some debate on this), but there is so much unknown when it comes to how the ocean interacts with the atmosphere, heat transfer within the ocean and with the surface, etc. And oceans cover, what, 70% of the earth? That's a huge variable in the equation, especially when it comes to how fast the surface warms.

[skierinvermont]

If OHC is being stored deeper than previously thought, then climate models need to be readjusted for temperature change in the next century.

I used to think that as well.. but if you understand the physics you learn that it makes very little difference. If the oceans have more overturning than previously thought (sending warmed water into the depths and bringing cold water to the surface), it will only increase the rate of heat gained by the oceans. Surface temperatures must closely follow net radiative forcing... if they do not then the earth just gains heat faster until they do.

You, as I used to, think that the earth gains X amount of heat every year and it can either go into the ocean or atmosphere. If more of it is going into the oceans (because the oceans more effectively mix it deep down), less is going into the atmosphere. However, the rate the oceans absorb heat is entirely determined by the surface temperature of the ocean. (*This is the key). In order to absorb more heat, the surface temperature of the ocean must be colder. If the surface temperature of the ocean is colder, it radiates less heat to space. Thus the earth would no longer be absorbing only X amount of heat every year, it would be absorbing 1.5X or 2X or 5X, until the oceans warmed up.

In the long run, greater overturning and thus deep ocean heat storage actually causes faster surface warming because 1) it speeds the time to reach climate equilibrium with net radiative forcing, and 2) it causes the oceans to absorb less CO2

We've discussed this before and you didn't seem to think through my explanation very clearly.. I am begging you read this carefully and think about it, because I have read and thought about this extensively and it is pretty straightfoward I am just explaining it poorly.

And this is backed up by climate models as well.. climate models which show greater vertical mixing of the oceans show just as much warming in the long run.

[skierinvermont]

You just said that our detection system now isn't good enough to know the exact OHC trend. How do you know that during that -PDO/-ENSO period in the 50s and 60s, the ocean wasn't storing heat that we weren't detecting, well below the surface? We just don't understand oceanic circulations enough to make definitive statements like that.

The potential trend error is highly dependent on the length of the period we are talking about. The slowing down is only 2002-2009 (and only at 0-700m). The Levitus data shows a negative trend from 1955-1970 (data begins in 1955).

15 years vs 7... that's why the uncertainty is less.

[ORH_wxman]

Global SSTs have flat lined or slightly fallen during the OHC flat line. Global temps have flat lined. Something doesn't add up. If the ocean is truly absorbing more heat, then sea level rise wouldn't be slowing either.

Your argument would make sense if we actually saw warming SSTs and sea level rise accelerating during the period where OHC/global temps have been flat lining.