Is the planet warming?- truly independent study a resounding YES

[tacoman25]

That makes absolutely no sense. Why would I want to define something in such a way that I can call it wrong as if I have something against the very word itself?

What I am against is people who do not accept/understand the consensus science supporting 1.5C+ of warming by 2100 under an A1B-like scenario.

I have nothing against the word 'skeptic.'

I just don't think it is very useful to call people, like me, who accept the likelihood of 1.5C of warming and associated serious consequences 'skeptics.'

I didn't say you had anything against the term. But you are intent on painting skeptics as unscientific morons, and that's easier if you can just group them all together.

[WeatherRusty]

That makes absolutely no sense. Why would I want to define something in such a way that I can call it wrong as if I have something against the very word itself?

What I am against is people who do not accept/understand the consensus science supporting 1.5C+ of warming by 2100 under an A1B-like scenario.

I have nothing against the word 'skeptic.'

I just don't think it is very useful to call people, like me, who accept the likelihood of 1.5C of warming and associated serious consequences 'skeptics.'

And how can anyone suspect that a warming of even 1.5C will not raise sea levels measured in feet? Even 1.5C is serious business.

I don't want to hear that it has happened many times in Earth's history. If that happens now we have very serious problems ahead of us.

[skierinvermont]

Think about it: if there was about .5C of warming from 1970-2000, and with a -PDO over most that period there only would have been .3C warming, that would still would be about .10C/decade warming over that period, which I believe would be within AGW forcing expectations for that time period.

There is nothing remarkable about the number I threw out (which I said I didn't know for sure if was accurate).

No it wouldn't be within forcing expectations and that is besides the point. Do you have any idea the magnitude of energy imbalance that would be caused by a .2C internally forced temperature change?

There is no study to support that large a response to the PDO.

[ORH_wxman]

And how can anyone suspect that a warming of even 1.5C will not raise sea levels measured in feet? Even 1.5C is serious business.

I don't want to hear that it has happened many times in Earth's history. If that happens now we have very serious problems ahead of us.

IPCC's most ambitious scenario is less than 2 feet. 1.5C of warming would obviously be under that. But not to go too OT.

[tacoman25]

No it wouldn't be within forcing expectations and that is besides the point. Do you have any idea the magnitude of energy imbalance that would be caused by a .2C internally forced temperature change?

There is no study to support that large a response to the PDO.

1. Ok, so what would be the range of expected warming for 1970-2000, based on AGW forcing? And even if it fell out of that range, that would only mean the underlying warming was being masked, just as it has been the last decade to an extent.

2. Please explain the ramifications of this energy imbalance. Doesn't the same thing occur with ENSO all the time?

[skierinvermont]

IPCC's most ambitious scenario is less than 2 feet. 1.5C of warming would obviously be under that. But not to go too OT.

That's by 2100. The IPCC also says that by 2C of warming we would likely have committed ourselves to at least 8 meters of sea level rise.

[skierinvermont]

1. Ok, so what would be the range of expected warming for 1970-2000, based on AGW forcing?

2. Please explain the ramifications of this energy imbalance. Doesn't the same thing occur with ENSO all the time?

1. Essentially what actually occurred. Externally forced models do a good job of reproducing the last 60 years of temperature.

2. Yes the same thing occurs with ENSO but only for a year or two. If the surface were persistently colder than the externally forced equilibrium temperature, then the earth would gain an incredible amount of heat, bringing the temperature closer to equilibrium.

[ORH_wxman]

That's by 2100. The IPCC also says that by 2C of warming we would likely have committed ourselves to at least 8 meters of sea level rise.

Oh, was only talking about the next 90 years. I've heard people make claims of 2m of sea level rise by 2100.

[tacoman25]

That's by 2100. The IPCC also says that by 2C of warming we would likely have committed ourselves to at least 8 meters of sea level rise.

The IPCC has changed their sea level numbers quite a bit over the years, so I wouldn't put much stock in these numbers.

[tacoman25]

1. Essentially what actually occurred. Externally forced models do a good job of reproducing the last 60 years of temperature.

2. Yes the same thing occurs with ENSO but only for a year or two. If the surface were persistently colder than the externally forced equilibrium temperature, then the earth would gain an incredible amount of heat, bringing the temperature closer to equilibrium.

1. I believe the 1970-2000 rise was actually on the high end of the spectrum, though, was it not? And you didn't answer what the range was...

2. I think it's likely that this "imbalance" is evened out when the PDO switches phases, just as when ENSO flips.

[WeatherRusty]

No it wouldn't be within forcing expectations and that is besides the point. Do you have any idea the magnitude of energy imbalance that would be caused by a .2C internally forced temperature change?

There is no study to support that large a response to the PDO.

If the PDO actually does impart a global temperature change it's effect should be measurable, whether it be by altered ENSO variability on temperature or more directly. Drawing on your statistical background, is a low frequency signal more difficult to tease out of noise than a higher frequency such as from ENSO? It seems to me that if PDO produced a 0.3C temperature variance it would be rather easy to detect, yet I'm not sure the magnitude in terms of PDO has been determined if its there at all.

[skierinvermont]

The IPCC has changed their sea level numbers quite a bit over the years, so I wouldn't put much stock in these numbers.

The long-term prediction has very high confidence based on paleoclimo. We know that Greenland has melted entirely at temperatures less than 2C higher than present.

[WeatherRusty]

IPCC's most ambitious scenario is less than 2 feet. 1.5C of warming would obviously be under that. But not to go too OT.

That would be through this century. Greenland and Antarctica will continue melting for centuries.

[tacoman25]

It's fascinating how the fixation on AGW causes some people, scientists included, to turn a blind eye to natural climate change/variation. It's like anything that could possibly distract from the all-important AGW Monster is shunned or downplayed.

[WeatherRusty]

It's fascinating how the fixation on AGW causes some people, scientists included, to turn a blind eye to natural climate change/variation. It's like anything that could possibly distract from the all-important AGW Monster is shunned or downplayed.

I will entertain the possibility of some amount, but do you really think +PDO accounts for as much as 0.3C since about 1970?

[skierinvermont]

If the PDO actually does impart a global temperature change it's effect should be measurable, whether it be by altered ENSO variability on temperature or more directly. Drawing on your statistical background, is a low frequency signal more difficult to tease out of noise than a higher frequency such as from ENSO? It seems to me that if PDO produced a 0.3C temperature variance it would be rather easy to detect, yet I'm not sure the magnitude in terms of PDO has been determined if its there at all.

Yes a low frequency signal is much harder to tease out over the same time period as a high frequency one. I think the best way to estimate the potential effect of the PDO is to assume that the primary way the PDO effect global temp is via change in ENSO frequency and that there is no cumulative effect but that the change in ENSO frequency leads to lower temperatures according to the normal ENSO-temp correlation. I'd guess the cumulative residual effect of the -PDO after removing ENSO effect on temperature could even be warming because the oceans would gain more heat during each successive La Nina.

The ONI averaged +.25 during the +PDO so if we assume the ONI varies by +/- .25 from -PDO to +PDO then applying the usual ESNO-temp correlation that would equate to +/-.03C from -PDO to +PDO.

[skierinvermont]

IPCC's most ambitious scenario is less than 2 feet. 1.5C of warming would obviously be under that. But not to go too OT.

Also the IPCC assumes and strongly cautions that these estimates do not include any acceleration in ice sheet mass loss. This is probably false... as we see in Greenland the glaciers are accelerating.

[ORH_wxman]

It's fascinating how the fixation on AGW causes some people, scientists included, to turn a blind eye to natural climate change/variation. It's like anything that could possibly distract from the all-important AGW Monster is shunned or downplayed.

There's been more literature recently talking about the natural ocean cycles contributing to the post-1980 warming. It used to not really be considered until within the last 5-10 years anyway. I do remember one coming out this summer that said that the natural multi-decadal variability of the oceans likely contributed about +.05C (could have been more, but the .05C is in my head) per decade in the 25 year period from 1980-2005. Hopefully I can find the link to it. (edit: it was Wu et al 2011)

We already saw the one that was co-authored by Phil Jones about the extreme drop in northern hemisphere ocean temps over a 4 years period from '68 to '72.

[tacoman25]

I will entertain the possibility of some amount, but do you really think +PDO accounts for as much as 0.3C since about 1970?

Well, what I originally meant was the swing between +PDO and -PDO could be .2 to .3C. So the actual additional amount to the underlying warming trend would be more like .15C.

[skierinvermont]

There's been more literature recently talking about the natural ocean cycles contributing to the post-1980 warming. It used to not really be considered until within the last 5-10 years anyway. I do remember one coming out this summer that said that the natural multi-decadal variability of the oceans likely contributed about +.05C (could have been more, but the .05C is in my head) per decade in the 25 year period from 1980-2005. Hopefully I can find the link to it. (edit: it was Wu et al 2011)

We already saw the one that was co-authored by Phil Jones about the extreme drop in northern hemisphere ocean temps over a 4 years period from '68 to '72.

Assuming this is the Wu et al 2011 you are referring to, it doesn't conclude anything like that:

http://www.springerl...14/fulltext.pdf

Aha just found Wu's more recent paper.

http://www.springerlink.com/content/akh241460p342708/fulltext.pdf

[ORH_wxman]

Assuming this is the Wu et al 2011 you are referring to, it doesn't conclude anything like that:

http://www.springerl...14/fulltext.pdf

No that's def not it. That doesn't say anything about global temps in the abstract.

[The_Global_Warmer]

What drives the PDO?

[skierinvermont]

What drives the PDO?

I'm not sure and I don't know if anybody knows. I did read something tonight which mentions that the PDO may be more driven by ENSO than the other way around. And that makes some sense to me. The PDO could really just be a period of frequent La Ninas.. in which case the question becomes, what causes frequent La Ninas?

[skierinvermont]

Food for thought.. need to read more on this but thought I would post anyways:

http://www.springerlink.com/content/akh241460p342708/fulltext.pdf

http://www.mendeley.com/research/significant-component-unforced-multidecadal-variability-recent-acceleration-global-warming/

http://eprints.ifm-geomar.de/8740/1/semenov.et.al.arctic.warming.jcl2010.accepted.pdf

[gracetoyou]

There are many modes of variability superimposed on the background trend. PDO is one of them. PDO warms as the overall climate warms. If we could strip away all other cases of internal variability other than PDO, the phasing of PDO would be seen to imprint a non-uniform oscillating waveform over the background trend. The high points of PDO would represent the warmest periods, but the warmest periods would be seen to be warming generally along with the background trend. It is the background trend which represents warming, not the PDO.

PDO warms as the overall climate warms.

What???

I'm sure you made a mistake unless you believe that PDO is now negative because of global cooling.

[gracetoyou]

But the point of "climategate" was to discredit the instrumental temperature record. Lots of folks question whether the world has been warming, including the Republican Party. They have even voted on it, and they denied the warming.

Politics should not be considered or an influential factor in this discussion. Unfortunately, I'm afraid that politics is the key factor as to why some are interested in studying this climate debate.

[WeatherRusty]

Well, what I originally meant was the swing between +PDO and -PDO could be .2 to .3C. So the actual additional amount to the underlying warming trend would be more like .15C.

A cursory reading of the links provided by Skier would tend to support a figure of about 0.15C. One study finds 0.8C/decade, another estimates as much as 1/3 of late 20th century warming could be due to multi-decadal oscillations and internal variability.

[WeatherRusty]

What???

I'm sure you made a mistake unless you believe that PDO is now negative because of global cooling.

There is no mistake there. As average SST rise so will the baseline PDO. Unless you totally deny any externally forced temperature increase.

[WeatherRusty]

Politics should not be considered or an influential factor in this discussion. Unfortunately, I'm afraid that politics is the key factor as to why some are interested in studying this climate debate.

The purpose of the BEST study was to provide a high profile reexamination of the instrumental surface temperature record in response to the doubt cast primarily by the "climategate" episode. If GISS, NOAA and Hadley were fudged data this new study was intent on finding so. They ended up confirming the results of those agencies. End of controversy. But let's wait for peer-review to be consistent.

[gracetoyou]

There is no mistake there. As average SST rise so will the baseline PDO. Unless you totally deny any externally forced temperature increase.

So do you believe the globe is in the process of cooling now.