Debate among scientists about Global Warming vs Active Cycle

[x-y-no]

XY, exactly what evidence that contradicts global warming do you dispute.

1) That the most monitored glacier in the world isnt thickening.

What's that supposed to prove? Global warming does not imply (let alone require) that temperatures and precipitation rates change uniformly at all locations.

Globally, glaciers are shrinking.

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2) That space based temperature readings show a .1 degree increase in world temp in last 30 years.

Both the Microwave Sounding Unit (MSU) and radiosonde records show the upper stratosphere cooling predicted by models to result from greenhouse gas increases. You are presumably referring to the upper troposphere calculations done by Spencer and Christy at UAH. Substantial problems have been found with these calculations, and have been aknowledged by the UAH group. Rather than try to put this issue in my own words, I'll just quote this discussion of the issue (from http://www.realclimate.org/index.php?p=170)

There have been three principle MSU products: Channel 4, Channel 2 and the 2LT records. MSU-4 is a record of lower stratospheric temperatures, MSU-2 is mainly mid-troposphere combined with a significant chunk of the lower stratosphere, and MSU-2LT is an attempt to use more viewing angles to try remove the stratospheric influence from MSU-2 and leave a lower-tropospheric record. (Recent upgrades to newer satellite instruments with more channels have lead to the 2LT record being renamed the TLT record).

The disagreement with the models related mainly to the MSU 2LT record. Models do quite well at matching the history of MSU-4 (whose variability is a function mainly of ozone depletion and volcanic aerosol effects), and models also match the lack of significant trend in MSU-2 (which is affected by stratospheric cooling and tropospheric warming which cancel out to some degree) (i.e Hansen et al 2002). So the problem has been principally with MSU 2LT, which despite a strong surface temperature trend did not seem to have been warming very much - while models and basic physics predict that it should be warming at a slightly larger rate than the surface.

In the first Science Express paper, Mears et al produce a new assessment of the MSU 2LT record and show that one of the corrections applied to the UAH MSU 2LT record had been applied incorrectly, significantly underplaying the trend in the data. This mistake has been acknowledged by the UAH team who have already updated their data (version 5.2) so that it includes the fix. This correction (related to the drift in crossing times at the equator) mainly affects the tropics, and was most important for one particular satellite (NOAA-11). Interestingly, Fu and Johansen (2005) singled out this same satellite and this same correction as being the source of divergence between the different records, though without being able to say exactly what the problem was. The fix leads to an increase of about 50% in the UAH global mean trend (0.086 to 0.12 deg/decade). The new RSS version of the 2LT record still shows a higher trend (0.19 deg/decade), with the difference being due to the methodology used to splice the different satellites.

In a related paper, Santer et al compare the surface/lower-troposphere coupled tropical variability at different timescales in the data and in model simulations performed for the new IPCC assessment. At monthly timescales (which should not be affected by trends in the model or possible drifts or calibration problems in the satellites or radiosondes) there is a very good match. In both models and data there is the expected enhancement of the variability in the lower-troposhere (based simply on the expected changes in the moist adiabatic lapse rate as the surface temperature changes). The models have large differences in their tropical variability (which depends on their represenation of El Nino-like processes in the Pacific) but the results all fall on a line, indicating that the lower tropospheric amplification is robust across a multitude of cloud and moist convective parameterisations.

At longer (decadal) time scales, the models still show very similar results (which makes sense since we anticipate that the tropical atmospheric physics involved in the trend should be similar to the physics involved at the monthly and interannual timescales). However, the original UAH 2LT data show very anomalous behaviour, while the new RSS 2LT product (including the latest correction) fits neatly within the range of model results, indicating that this is probably physically more consistent than the original UAH data.

So, this alleged discrepancy has apparently been cleared up.

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3) That all the increase of 1 degree since 1875 was a rebound of a cooling trend which leveled off in the 30's.

You're going to have to provide the evidence for this claim, since I'm not aware that it really exists.

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4) That the midlevel atmosphere shows almost no change at all.

See the response to number (2).

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Those hearalded computer models indicate a 10 degree increase in global temps by 2100. The last time that happened 300 million years ago 98% of all life was lost. Hardly a likely scenario.

I'm not aware of any major extiction 300mya. You are perhaps referring to the end of the Permian period. Even though that was the greatest extiction event on record, however, it still did not come anywhere near wiping out 98% of all life. More like 54%. Furthermore, I'm not aware that the cause of the Permian extinction has been definitively determined.

It's notable, however, that even though climate change has yet to have very large impact, we are already in the midst of an extinction event (with a rate of species loss in the tens of thousands per year) whose rate is on a scale with any and all of the great extinction events in the past. I'd say it's legitimate to be concerned about what compounding effect rapid climate change would have on that.

[terstorm1012]

I think the Permian Extinction has been linked to an asteroid impact--there are impact craters in Canada that correspond to the period of the Event, or something that caused a massive dry spell on Earth as well (my source for the second part is a Discovery Channel/BBC TV show I watched not too long ago).
I've read some more fanciful explanations ---aliens did it to mold a world more in their own image. I do, however, read far too much sci-fi --the basis of that argument is that all life that came thereafter is significantly different than the life that preceeded the Extinction.

The 90% is accurate though, I've seen that figure quite often.

And you are right about our current extinction event...humans are pretty good at making other species disappear. It is our nature.

[x-y-no]

The 90% is accurate though, I've seen that figure quite often.

And you are right about our current extinction event...humans are pretty good at making other species disappear. It is our nature.

I think I see where the discrepancy was - the number that was stuck in my head was the percentage of families, the 90% plus figure is species.

[curtadams]

Those hearalded computer models indicate a 10 degree increase in global temps by 2100. The last time that happened 300 million years ago 98% of all life was lost. Hardly a likely scenario.

This is a factually false statement but it indicates a fundamental conceptual error. If a scientifically based validated model indicated that life on earth was going to get whomped by temperature change in 100 years then it *would be* a likely scenario - preconceptions that the event was unlikely would be wrong (depending on the strength of the models, etc.) Facts beat common sense - the world is round in spite of looking flat.

The factual falsities:
The superextinction to which you refer is the end-Permian extinction. It was not caused by warming, but the cause is not known. Plausible candidates include the largest volcanic eruption in history (leaving the Siberian Traps), a comet impact off Australia, and an iceball event leaving glaciers at the equator.

The biggest warming known is the Eocene warming, which was around 55 million years ago. There was a lot of extinction, but it's not normally considered an extinction event since there was a lot of speciation at the same time. It's estimated at 7 degrees C.

The computer models show a range of 2 to 11 degrees C warming over the next century. The range is wide since a lot of variables aren't well-measured or will be outside historical ranges, requiring that we extrapolate the effects. Even the low end, however, will take us out of the range of interglacial periods so drastic climate change is pretty much guaranteed. We don't know the effects but big weather changes are almost always bad because we have to adjust to them. Several plausible events will cause economic and social catastrophe and unfortunately we won't know for sure they're going to happen until they start.

[Jim Hughes]

So here is what I am trying to find out from certain people. Could you at least give me a time frame of when global warming became influential if you believe that it has been playing a part in the heightened level of activity in the Atlantic Basin.

I do not expect the year but maybe the decade or quite possibly even within 5-7 years. The recent wind shear patterns, or lack there of, have been related to the increase along with the warmer SST's. These favorable wind directions have also directed storms towards the GOM.

So am I wrong in assuming that this possible relationship has really kicked in the past few years or am I wrong about this?

Any response would be appreciated. A fairly shorter time span would make it easier for me to point certain things out in relation to what has been going on. This is a big maybe of course. But I will give it a shot in good time.




Jim

[johngaltfla]

XY, exactly what evidence that contradicts global warming do you dispute.

1) That the most monitored glacier in the world isnt thickening.

2) That space based temperature readings show a .1 degree increase in world temp in last 30 years.

3) That all the increase of 1 degree since 1875 was a rebound of a cooling trend which leveled off in the 30's.

4) That the midlevel atmosphere shows almost no change at all.

Those hearalded computer models indicate a 10 degree increase in global temps by 2100. The last time that happened 300 million years ago 98% of all life was lost. Hardly a likely scenario. You can not dismiss these findings outright unless like Jim said the data is manipulated.

Sponger, all the facts in the world do not matter. The bottom line is the catch phrase "global warming" has been developed for political and economic purposes, not scientific realism. If anyone looks at the data available to scientists via the use of ice core measurements, they would recognize that our eath undergoes warming and cooling cycles.

But for the purpose of today's debate, attributing increased hurricane activitiy, despite ZERO scientific evidence to back that point (because there is not enough data to validate it, just guesses and theories), to global warming has become the big "in" thing to do.

But once again, if global warming is the cause, then what excuses are there for increased hurricane activity pre-1940? Pre-1900? Pre-1700

Etc....

There is no answer to that question because you can't take the last 5 years as the gospel and say because of X we have Y. It's not only bad science but just plain ignorant of the facts. WE have only been measuring these storms for 150 plus years. So to attribute a sudden cyclical spike to another geological and climatalogical event is as much as a reach as saying that I will win the Lottery Saturday night because I need the money.

Your posting underlines the facts, but that's not good enough. Facts are not going to win or lose this discussion. The reality is that if you look at the history of these storms, we were due for a cyclical uptick. The impact is more widespread now because man has ignored history, as usual, and overbuilt along the coastlines.

Thank you for your points as they were all well made.

[x-y-no]

Sponger, all the facts in the world do not matter.

Why do you ignore my point-by-point reply to sponger? Is it because it's inconvenient to your chosen world-view that such answers exist?

The bottom line is the catch phrase "global warming" has been developed for political and economic purposes, not scientific realism. If anyone looks at the data available to scientists via the use of ice core measurements, they would recognize that our eath undergoes warming and cooling cycles.

But for the purpose of today's debate, attributing increased hurricane activitiy, despite ZERO scientific evidence to back that point (because there is not enough data to validate it, just guesses and theories), to global warming has become the big "in" thing to do.

If you have been following the various threads of this discussion, then you ought to be aware that I have repeatedly stated that there is no dispute about the existence of natural cycles or that a substantial part of the current upturn in activity appears to be related to a natural cycle.

I have repeatedly pointed out that the existence of natural cycles does not preclude the existence of anthropogenic forcing superimposed on those cycles. None of those arguing on the contrarian side have deigned to even aknowledge, let alone respond to this point. Is that because it is inconvenient to your chosen world-view?

I have pointed out that there is indeed scientific evidence of increased cumulative cylone energy worldwide. Thus your claim that there is "ZERO scientific evidence" is false. Now we can discuss possible difficulties with the data sets used to reach these results (and I don't reject the possibility, especially given the newness of these results) but that's a very different thing from the assertion that no such evidence exists.

I have also made a qualitative argument that I don't understand the reasoning that allows contrarians such as Dr. Gray to do seasonal forecasting which is based in part on SSTs in the tropical Atlantic basin (showing a positive correlation) whist simultaneously arguing that the incremental increase in those SSTs due to AGW cannot possibly be resulting in increased activity. This juxtaposition seems counterintuitive at best, and I think needs more than just a "because I say so" as justification. And yet no one arguing the contrarian side in thes threads has chosen to even aknowledge, let alone respond to this argument. Is that because it is inconvenient to your chosen world-view?

But once again, if global warming is the cause, then what excuses are there for increased hurricane activity pre-1940? Pre-1900? Pre-1700

Etc....

I have answered that question over and over again. Nobody disputes the importance of natural cycles to any and all weather, including hurricane activity. But I'll ask this again and maybe this time one of you will have the courtesy to reply: does the fact that forest fires occur naturally prove that no forest fires are caused by man? If not, why would that same form of argument be valid when it comes to man-made climate forcing?

There is no answer to that question because you can't take the last 5 years as the gospel and say because of X we have Y.

But there is and answer and I have repeatedly given it. And yet no one arguing the contrarian side in thes threads has chosen to even aknowledge, let alone respond to this answer. Is that because it is inconvenient to your chosen world-view?

It's not only bad science but just plain ignorant of the facts. WE have only been measuring these storms for 150 plus years. So to attribute a sudden cyclical spike to another geological and climatalogical event is as much as a reach as saying that I will win the Lottery Saturday night because I need the money.

Your posting underlines the facts, but that's not good enough. Facts are not going to win or lose this discussion. The reality is that if you look at the history of these storms, we were due for a cyclical uptick. The impact is more widespread now because man has ignored history, as usual, and overbuilt along the coastlines.

Thank you for your points as they were all well made.

Would you do me the courtesy of reading and responding to the replies I made to all of those points, or is actual debate on the facts too daunting a prospect?

[terstorm1012]

http://www.csmonitor.com/2005/1130/p03s02-usgn.html


Add more fuel to the debate. A very balanced article, but the CSM is well known for that. I love their coverage.

[x-y-no]

So here is what I am trying to find out from certain people. Could you at least give me a time frame of when global warming became influential if you believe that it has been playing a part in the heightened level of activity in the Atlantic Basin.

Pinning down a start date in any meaningful way would require a better understanding of how big any current effect is. Obviously, we're talking about the last decade or two at most, however, with any influence gradually growing over that time.


At the moment, my argument is confined to saying that there seems to me to be good reason to suspect that some relatively small fraction of the total intensity of recent seasons is attributable to AGW related SST increase, and that one would expect the size of that effect to continue to grow as the Earth warms more over the next couple of centuries.

[sponger]

XY, I would have to say that the recent increase in activity is a likely effect of warmer water (predicted in 1970 by Grey, and much more favorable atmospheric conditions.

Now I still have a hard time swallowing the idea that a minor rise in air temp can have any meaningful heating effect on ocean temperature.

Now if you say global warming is causing the atmosphere to be more favorable, that may be worth looking into.

Great debate every one! Hope you all have a good weekend!

[MGC]

The atmosphere plays little role in the absorption of solar radiation by the oceans other than a few clouds. So I think the current phase of warm Atlantic Ocean waters are just a natural cycle that is occurring in phase with the warm atmospheric temperatures. Humans are not responsible for the warming Earth......MGC

[curtadams]

The atmosphere plays little role in the absorption of solar radiation by the oceans other than a few clouds. So I think the current phase of warm Atlantic Ocean waters are just a natural cycle that is occurring in phase with the warm atmospheric temperatures. Humans are not responsible for the warming Earth......MGC

The atmosphere can have HUGE effects on oceanic heat. Why do you think oceanic heat *capacity* is a significant limitation on hurricanes? A hurricane can suck several degrees of heat out of the ocean down over a hundred feet in a day or two - even when upwelling is impossible due to continental shelves. And didn't you notice the Gulf of Mexico get colder when those post-Wilma cold fronts came through?

[MGC]

Unless a cloud block the solar radiation about 95% of that radiation is absorbed by the water. I said absorption not radiation. Sure the atmosphere plays a huge roll in the radiation of the trapped heat.....MGC

[caribepr]

Would you do me the courtesy of reading and responding to the replies I made to all of those points, or is actual debate on the facts too daunting a prospect?

Obviously daunting indeed.

[MGC]

This from University of Colorado extended range forecast of Atlantic seasonal hurricane activity for 2006

"There have been similar past periods (1940s-1950s) when the Atlantic was just as active as in recent years. For instance, whe we compare Atlantic basin hurricane numbers of the last 15 years with an earlier 15-year period (1950-64), we see no difference in hurricane frequency or intensity even though the global surface temperatures were cooler and there was a general global cooling during the 1950-64 as compared with global wrming during 1900-2004."

So, as you can see Dr Gray's team don't think global warming is responsible for hurricane frequency or intensity of the past couple of seasons.

Section 8 of the paper offers interesting reading to the myth of global warming and increased hurricane activity.......MGC

http://hurricane.atmos.colostate.edu/Forecasts/2005/dec2005/

[x-y-no]

This from University of Colorado extended range forecast of Atlantic seasonal hurricane activity for 2006

"There have been similar past periods (1940s-1950s) when the Atlantic was just as active as in recent years. For instance, whe we compare Atlantic basin hurricane numbers of the last 15 years with an earlier 15-year period (1950-64), we see no difference in hurricane frequency or intensity even though the global surface temperatures were cooler and there was a general global cooling during the 1950-64 as compared with global wrming during 1900-2004."

So, as you can see Dr Gray's team don't think global warming is responsible for hurricane frequency or intensity of the past couple of seasons.

We were discussing the views of Dr. Gray's team earlier in the thread. I raised some issues I have with their reasoning, but none of you skeptics chose to offer any explanation or justification. Is it too much to expect a real dialogue? I have endeavoured to respond to points made, why won't you guys do the same?

Section 8 of the paper offers interesting reading to the myth of global warming and increased hurricane activity.......MGC

http://hurricane.atmos.colostate.edu/Forecasts/2005/dec2005/

All right ... let's take a look at "section 8".

There is no physical basis for assuming that global hurricane intensity or frequency is necessarily related to global mean surface temperature changes of less than ± 0.5oC. As the ocean surface warms, so too does global upper air temperatures to maintain conditionally unstable lapse-rates and global rainfall rates at their required values.

What's magical about 0.5oC? The claim here appears to be that the lapse rate and rainfall rate will adapt perfectly to a 0.5oC or less increase in SST, but then suddenly fail to do so for greater increase. This must neccesarily be their argument, since they themselves consider SSTs a primary factor in making their seasonal forecasts.

What's the reasoning behind this alleged shift in response of the lapse rate at the 0.5oC threshold? Is there any research whatsoever showing this alleged transition? I've never seen it.

But I note they've left themselves a clever out in that word "necessarily." IOW, what reads (and is presented in the media) as a categorical denial is in fact an equivocation. They merely assert in passage that the physical evidence isn't there to make an open-and-shut case for causality.

Seasonal and monthly variations of sea surface temperature (SST) within individual storm basins show only very low correlations with monthly, seasonal, and yearly variations of hurricane activity.

Excuse me??? I must have missed all those hurricanes we have all winter every winter in the Atlantic basin. And if this were true, why was every forecaster (including Dr. Gray) citing high SSTs in the MDR as one factor in predicting an above average season this year?

Other factors such as tropospheric vertical wind shear, surface pressure, low level vorticity, mid-level moisture, etc. play more dominant roles in explaining hurricane variability than do surface temperatures.

Certainly. But that doesn't mean SSTs play no role. Unless they can show why higher SSTs due to global warming (as opposed to higher SSTs due to any other cause) would neccesarily result in a systematic change in one of these other factors which offsets the effect of those higher SSTs, then this point is immaterial.

Although there has been a general global warming over the last 30 years and particularly over the last 10 years, the SST increases in the individual tropical cyclone basins have been smaller (about half) and, according to the observations, have not brought about any significant increases in global major tropical cyclones except for the Atlantic which as has been discussed, has multi-decadal oscillations driven primarily by changes in Atlantic salinity. No credible observational evidence is available or likely will be available in the next few decades which will be able to directly associate global surface temperature change to changes in global hurricane frequency and intensity.

This is the heart of their criticism of Dr. Emmanuel's and Dr. Webster's recent results. They claim the reliability of the data used is insufficient to draw any real conclusions. I don't dismiss this argument, clearly it merits rigorous examination. Personally, I think it's likely that their results are on the high side with regards to cumulative intensity.

But what continues to bug me is this public stance of categorical denial of any linkage from a group whose own seasonal forecast methodology implies a linkage. I just don't get it, and nobody arguing that side seems willing to offer any explanation.

[Sanibel]

NY Times reports a record drought in the Amazon.

Amazona state reports worst drought ever recorded. Large rivers drying up and cities cut off from their sources of livelihood and transportation. Food is having to be helicoptered in to communities. Rivers are drying up and people are unable to fish. Malaria is increasing due to formation of stagnant pools.

Some theorize the same high Atlantic SST's that caused the hurricanes have created uplifting Low pressure over the Atlantic increased by the heat energy. This uplifting air returns as subsiding High pressure over the Amazon Basin where it stifles cloud formation. Forest fires caused by the drought further inhibit cloud formation.

Luckily true rainy season is starting soon.


The Amazon is being deforested at record rates...

[Tampa Bay Hurricane]

NY Times reports a record drought in the Amazon.

Amazona state reports worst drought ever recorded. Large rivers drying up and cities cut off from their sources of livelihood and transportation. Food is having to be helicoptered in to communities. Rivers are drying up and people are unable to fish. Malaria is increasing due to formation of stagnant pools.

Some theorize the same high Atlantic SST's that caused the hurricanes have created uplifting Low pressure over the Atlantic increased by the heat energy. This uplifting air returns as subsiding High pressure over the Amazon Basin where it stifles cloud formation. Forest fires caused by the drought further inhibit cloud formation.

Luckily true rainy season is starting soon.


The Amazon is being deforested at record rates...

Amazon may be gone one day

[hcane]

I have followed with interest the preceding posts. As one who publicly has issued a tropical cyclone activity forecast for the last 5 years I would like to chime in on the discussion.
As has been mentioned, the apparent incongruity in the disclaimer that the warming of the Atlantic sst's has nothing to do with "global warming", but considerable influence on the Atlantic tropical activity is obvious. It is just such inconsistencies that brings into question the reliability of the forecasters' judgement, not necessarily the forecasts themselves.
The reference to "section 8" also raises some objectivity issues. As has been noted in another forum, rather heatedly, the information prior to 1975 as far as intensity of indvidual tropical cyclones is suspect, the information prior to 1960 (satellite-era) as to "numbers" is suspect. This would lead one to believe that using information prior to 1975 relating to either the frequency or intensity for studies or forecasts of any kind is truly suspect.
Unfortunately, that leaves us with very little "good" data to work with. This results in an apparent inability to make any "reliable" forecasts. That is, if you choose to define "reliable" as one based upon statistically reasonable premises.
Is the climate changing ??? I think there is little doubt. Does this change have an effect upon tropical cyclone formation/intensity ??? I think there is little doubt. But, we do not, and will not have the ability to accuratelty measure just how much of an effect this change is having for some time yet.
Now, as to the cause(s) of the climate change .........

[Tampa Bay Hurricane]

I have followed with interest the preceding posts. As one who publicly has issued a tropical cyclone activity forecast for the last 5 years I would like to chime in on the discussion.
As has been mentioned, the apparent incongruity in the disclaimer that the warming of the Atlantic sst's has nothing to do with "global warming", but considerable influence on the Atlantic tropical activity is obvious. It is just such inconsistencies that brings into question the reliability of the forecasters' judgement, not necessarily the forecasts themselves.
The reference to "section 8" also raises some objectivity issues. As has been noted in another forum, rather heatedly, the information prior to 1975 as far as intensity of indvidual tropical cyclones is suspect, the information prior to 1960 (satellite-era) as to "numbers" is suspect. This would lead one to believe that using information prior to 1975 relating to either the frequency or intensity for studies or forecasts of any kind is truly suspect.
Unfortunately, that leaves us with very little "good" data to work with. This results in an apparent inability to make any "reliable" forecasts. That is, if you choose to define "reliable" as one based upon statistically reasonable premises.
Is the climate changing ??? I think there is little doubt. Does this change have an effect upon tropical cyclone formation/intensity ??? I think there is little doubt. But, we do not, and will not have the ability to accuratelty measure just how much of an effect this change is having for some time yet.
Now, as to the cause(s) of the climate change .........

Excellent perspective. The statement that global warming doesn't
influence cyclone activity even though SSTs are such imperative
factors is dubious at best. The fact that SSTs are not the sole
influential factors in hurricane activity and intensity does not negate
the possibility that an increase in SSTs could have notable
implications for cyclone development and intensification.