Myth of "Consensus Science" Explodes, APS reverses stance

[TimBikes]

Sorry - my Case A, B, C attachment is not attaching. Trying again...

[MegansPrius]

Originally Posted by TimBikes

I agree - CO2 has risen much more significantly in the latter half of the 20th C than the first half. But then consider 3 cases as per the thumbnail attached below:
Case A (pre-1945) - minimal CO2 accumulation in the atmosphere yet temperatures rose approximately 0.3 C
Case B (1945-1975) - significant CO2 accumulation in the atmosphere, yet temperatures actually fell by approximately 0.2 C
Case C (1975 - present) - significant CO2 accumulation - though at a slightly lower slope than in case B, and temperatures rose by approximately 0.6 C

The only scenario that strongly correlates with CO2 driving significant warming is Case C. And Case A and B, while certainly not refuting AGW, beg the question as to what other factors might drive climate. Not knowing the answer, we cannot say with much certainty whether, or how much of, the warming in the latter half of the 20th C. is due to CO2.

My bet is on PDO, which does a much better job of tracking to temperature change than does CO2:

The scientists tracking the PDO don't seem convinced of its basic predictability, and make no mention of using it as a measure of climate change or CO2.

Pacific Decadal Oscillation (PDO)
The "Pacific Decadal Oscillation" (PDO) is a long-lived El Niño-like pattern of Pacific climate variability...Causes for the PDO are not currently known. Likewise, the potential predictability for this climate oscillation are not known.

And the site your picture comes from has not been update since the year 2000.

[TimBikes]

Originally Posted by MegansPrius

You're the one being disingenous. Oreskes published in Science, possibly, outside of Nature, the most prestigeous scientific publication extant. It is not equivalent to publishing an unreviewed opinion piece in a local newspaper (the route of 90% of the articles that dispute AGW). Had her piece been Opinion-driven, Science would have published it as an Editorial or perhaps Perspective. Instead, like most scientific articles, the Oreskes piece contained reproducible results.

Disingenuous? Sure Scott - you could believe in the absolute primacy of CO2 if you: ignore the importance of other non-CO2 factors such as AMO/PDO, land use/change, ignore solar variability / TSI, etc.; ignore Holocene warming that appears to be strongly linked to solar variability (not greenhouse gas forcing); ignore that temperatures over the past century (and in the current decade) have not moved in sync with CO2 over large spans of decades (see my case A, B, C post); ignore the fact that climate models do represent empirical data very well in many important instances and do not simulate many features of convective or large-scale precipitation characteristics; ignore the well documented deficiencies in the surface temperture record; and ignore satellite temperature readings which do not agree with the less reliable land-based temperature records.

Yep - if you ignore all of that, you might trust the history professor's "essay".

[F8L]

Thanks for those stats Tim.

My gut feeling on these cases are as follows:

Case A: Temperatures were on the rise due to other natural factors and as we know CO2 acts as an amplifier and does not neccessarily need to be a primary driver. In this case we may be experiencing the lag time between temp increase and eventual CO2 amplification.

Case B: 1945-1975 was part of the era of "dirty industry" and the added pollutants such as aerosols may have played a part in the "global dimming" pheonomenon and thus reduced observed global temperatures due to a reduction in photon activity at the ground level. This effect was observed from at least the 1960s to mid 1990s right? (Ohmura, A. 1989. "Secular variation of global radiation in Eurpoe", Liepert, B. 1994. "Solar Radiation in Germany", Stanhill, G. 1992)

Case C: As aerosols and soot levels delcine in the atmosphere and CO2 levels continued to rise we see the temperature resume its upward trend.

A recent slowing of that trend and at any other time in our records could have been modified by natural factors such as solar variation, energy distibution systems (water, air etc.), volcanic activity, etc.

We both agree that other "natural" factors are likely main drivers so it is hard to say when CO2 became a major factor but I believe that it is a main factor now that levels are so high compared to recent history.

[TimBikes]

Originally Posted by MegansPrius

The scientists tracking the PDO don't seem convinced of its basic predictability..

Yes - but is your point that because it is unpredictable it does not influence climate?

As for the PDO table, I don't have anything more current, though NASA has recently announced that PDO has shifted to a cool phase and this is expected to persist for decades.




"The image also shows that this La Niña is occurring within the context of a larger climate event, the early stages of a cool phase of the basin-wide Pacific Decadal Oscillation. The Pacific Decadal Oscillation is a long-term fluctuation of the Pacific Ocean that waxes and wanes between cool and warm phases approximately every five to 20 years. In the cool phase, higher than normal sea-surface heights caused by warm water form a horseshoe pattern that connects the north, west and southern Pacific, with cool water in the middle. During most of the 1980s and 1990s, the Pacific was locked in the oscillation's warm phase, during which these warm and cool regions are reversed. For an explanation of the Pacific Decadal Oscillation and its present state, see: Pacific Decadal Oscillation (PDO) and Earth and Space Resarch: Pacific Decadal Oscillation (PDO) index . "

As I said, PDO was likely responsible for much of the warming of the late 20th Century, but now it is waning and - surprise, surprise, we are seeing global cooling.

[TimBikes]

Originally Posted by F8L

We both agree that other "natural" factors are likely main drivers so it is hard to say when CO2 became a major factor but I believe that it is a main factor now that levels are so high compared to recent history.

We also both agree CO2 is a factor - but what % I don't know - but my sense is maybe it contributes around 1/4 to 1/3 of temp. increase. Not insignificant, but not catastrophic.

As for the aerosol argument, I have heard it before but am not convinced because as I understand it, there is no data that consistently and systematically has measured anthropogenic (or total, for that matter) atmospheric aerosols over time.

I think it is possible aerosols declined during the period as you mentioned. But I think it is more likely that as reductions in aerosols in the US and Europe phased in slowly over time they were likely offset, perhaps exceeded, by those of these and other economies (Mexico, China, India, eastern block countries, Korea, Taiwan, etc).

[MegansPrius]

Originally Posted by TimBikes

Yes. So what is your point - that because it is unpredictable it does not influence climate?

As I said, PDO was likely responsible for much of the warming of the late 20th Century, but now it is waning and - surprise, surprise, we are seeing global cooling.

Well, you appear alone in your opinion. The scientists who study and document the PDO make no such claims.
Pacific Decadal Oscillation (PDO)
Ocean Surface Topography from Space-Science
Ocean Surface Topography from Space-Newsroom

About the only person who agrees with you is Joseph D'Aleo (a weatherman), although his agreement is dependant upon using only U.S. temperature and excluding global data.

[TimBikes]

Originally Posted by MegansPrius

And the site your picture comes from has not been update since the year 2000.

Sorry - here is the more current...

http://jisao.washington.edu/pdo/

[F8L]

Originally Posted by TimBikes

We also both agree CO2 is a factor - but what % I don't know - but my sense is maybe it contributes around 1/4 to 1/3 of temp. increase. Not insignificant, but not catastrophic.

I sort of agree but is there a level where it could become catestrophic? Like a bifurcation point where just a little more CO2 can make large changes in the system?

As for the aerosol argument, I have heard it before but am not convinced because as I understand it, there is no data that consistently and systematically has measured anthropogenic (or total, for that matter) atmospheric aerosols over time.

I agree we are lacking in this area or at least I have not seen a lot of data on aerosol level history. We do have great data on localized areas over short periods of time that we can work with though.

I think it is possible aerosols declined during the period as you mentioned. But I think it is more likely that as reductions in aerosols in the US and Europe phased in slowly over time they were likely offset, perhaps exceeded, by those of these and other economies (Mexico, China, India, eastern block countries, Korea, Taiwan, etc).

Without a lot of historic data it is difficult to make any real conclusions on the subject. We can look at the data we have and make predictions but I agree it is hard to say definitively what effect aerosols have had on climate overall.

[PriusSport]

So this thread and its incorrect title still stands--despite being phoney and discredited.
I wish newsgroups would pay attention to phoney threads like this, which are planted by people with ideological agendas--mostly right wing these days--I should add.
Delete these threads--to discourage others with agendas.
This nonsense just cheapens a newsgroup. The American Physical Society is a scientific organization of high repute, and they don't like to see their name misrepresented by agenda-ridden ideologues.

Probably the biggest mistake newsgroups make is to have a political forum. This opens the door for wingnut invasion.