Is there an upside to global warming?

What I was more interested in was the seeming contradiction between the perspective that predictions of effects are so uncertain as to be considered poor science and yet the various science organizations most directly oriented to studying climate change all devote a considerable effort toward providing (and explaining) predictions.
Click to expand...
The problem is not with them but with your expectations.

They don't predict - they cannot predict - as we are the major variable
The science bodies set ranges of outcomes and from that range....some will go further and say if the world climate hits x degrees due to AGW these are probable impacts in various areas.

http://www.globalwarmingisreal.com/...imate-change-is-going-to-be-twice-as-extreme/

Scenarios are not predictions - they are possible outcomes based on the known science.
 
macdoc said:
Minor but serious due to S02 and carbon black.
They likely have a net cooling effect right now.
Click to expand...

I don't think "minor" is an appropriate qualification for these emissions which total more than air transport and account for close to 4% of total human CO2 emissions. Shipping rates have already increased by more than 75% over the last 15 years, any significant increase in this rate (which is what I was cautioning against) is undesirable if pursued using current technologies and methods.
 
macdoc said:
The problem is not with them but with your expectations.

They don't predict - they cannot predict - as we are the major variable
The science bodies set ranges of outcomes and from that range....some will go further and say if the world climate hits x degrees due to AGW these are probable impacts in various areas.

http://www.globalwarmingisreal.com/...imate-change-is-going-to-be-twice-as-extreme/

Scenarios are not predictions - they are possible outcomes based on the known science.
Click to expand...


You seem to be wrapping yourself in a semantic web of your own weaving.

Both of the scientific sources referenced, the IPCC reports and the NAS statements use the specific term "prediction" in the same manner I have. If you wish to create a distinction between the terms that holds some significant meaning, then I will be happy to entertain your argument, but I use the term as the cited references employ it.

Prediction:
To foresee using observation, experience, or scientific reason.
science.education.nih.gov/supplements/nih2/oral-health/other/glossary.htm

A statement (usually quantitative) about what will happen under specific conditions, as a logical consequence of scientific theories.
www.umetrics.com/default.asp/pagename/methods_over_dict/c/3​

Senario:
an imagined or projected sequence of events, esp. any of several detailed plans or possibilities.
http://dictionary.reference.com/browse/scenario

An outline or model of an expected or supposed sequence of events:
http://www.thefreedictionary.com/scenario​

Climate prediction
A climate prediction or climate forecast is the result of an attempt to produce
an estimate of the actual evolution of the climate in the future, for
example, at seasonal, interannual or long-term time scales. Since the future
evolution of the climate system may be highly sensitive to initial conditions,
such predictions are usually probabilistic in nature. http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_appendix.pdf​

If, however, this is the sole basis of the reticence to my line of inquiry, I would happily forego a response on issues of prediction and gladly substitute projection or senario if that makes it easier to answer and more appropriately phrased from your, and Matt's perspective. If it were a simple issue of terms that could have long ago been brought up and resolved.
 
DogB said:
So over time the signal appears from the noise. That makes sense.

That said, what about medium term variability like the PDO ( assuming it's a real effect)?
Click to expand...

Keep in mind that in the case of climate the noise is a product of the chaotic nature of the system so it exists in all realizations, including the real world observations.

PDO is included in the models in two different ways, where it’s known empirically the observed PDO is entered as a parameter. Where it isn’t it’s modeled. The modeled PDO shows the same general characteristics as the observed PDO but can differ significantly for any given year or decade. Since it’s longer term characteristics are the same, however so the effects drop out of the result past about 20-30 years or so, but for shorter times then that it’s a major contributor to internal variation.
 
TS - lose the verbosity - it's wearisome

The "predictions" you refer to are based on models.
Your expectation of a model against real world is either flawed - or you don't perhaps realize that the IPCC range of outcomes have been matched in observation with the exception of Arctic ice which they acknowledged was poorly served in their report.

http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/

a model "prediction" is very different than a real world prediction.
 
lomiller - you are talking global models not regional I assume.?

I would think the PDO has some significant regional impact even within the last 30 years but I know regional models are still "work in progress".
 
macdoc said:
Your expectation of a model against real world is either flawed - or you don't perhaps realize that the IPCC range of outcomes have been matched in observation
Click to expand...
Only if you are computer illiterate do you think those projections even remotely match the biased GISS and CRU data.
 
Even in 2003 regional hindcasting produced robust results.

Evaluations of the hindcast suggest that the RCM-generated regional-scale fields are reasonably accurate, and preserve the large-scale information of the driving coarse-resolution data well. This refined spatial variability is crucial for regional climate and climate impact assessment studies, especially in mountainous regions such as the western United States, where the spatial and temporal variations of the hydrologic cycle depend strongly on terrain height.
Click to expand...

http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1525-7541(2003)004<0878%3AAMRCHF>2.0.CO%3B2

moving forward

Improved Skill of Northern Hemisphere Winter Surface Temperature Predictions Based on Land-Atmosphere Fall Anomalies

Article from:
Journal of Climate
Article date:
August 15, 2007
Author:
Cohen, Judah; Fletcher,

A statistical forecast model, referred to as the snow-cast (sCast) model, has been developed using observed October mean snow cover and sea level pressure anomalies to predict upcoming winter land surface temperatures for the extratropical Northern Hemisphere. In operational forecasts since 1999, snow cover has been used for seven winters, and sea level pressure anomalies for three winters. Presented are skill scores for these seven real-time forecasts and also for 33 winter hindcasts (1972/73-2004/05). The model demonstrates positive skill over much of the eastern United States and northern Eurasia-regions that have eluded skillful predictions among the existing major seasonal ...
Click to expand...
http://www.highbeam.com/doc/1P3-1325480521.html

and up to date

http://wcrp.wmo.int/ClimatePrediction_index.html

Perhaps getting out of the 90s might be a useful endeavour :garfield:
 
Last edited:
BenBurch said:
So, you would rather a calamity occurs than to take heed of a scientific prediction.
Click to expand...

If you are addressing this to me, I'm afraid you have me by the wrong side of the discussion. If anything, I believe the IPCC and NAS projections to be highly conservative, especially in light of what is currently coming to be understood about these issues.
 
macdoc said:
TS - lose the verbosity - it's wearisome.
Click to expand...

Not sure what you mean, I'm speaking in my natural, real-world voice, but while we're at it, how about sticking to the issues at hand and dropping the personal attacks and insults.


The "predictions" you refer to are based on models.
Your expectation of a model against real world is either flawed - or you don't perhaps realize that the IPCC range of outcomes have been matched in observation with the exception of Arctic ice which they acknowledged was poorly served in their report.

http://www.realclimate.org/index.php/archives/2008/05/what-the-ipcc-models-really-say/

a model "prediction" is very different than a real world prediction.
Click to expand...


Nice reference, though largely irrelevent to any issue at hand or under current discussion.

I'm not arguing that IPCC predictions are Iron-clad detailed prognostications of what will happen with zero chance of error or alteration. What I do believe that both the IPCC and NAS findings do indicate, however, is that if things continue along their current course, we can pretty much expect to see certain generalized effects in the coming decades/centuries. I am trying to reconcile this with the apparent statements by some that they base their understandings of climate change on the IPCC and NAS findings, but do not think that neither science nor we can make any reasonable projections about what will happen in the future based upon current climate knowledge and understandings.

I've tried to drop this as the party in question is not interested in clarifying their position, I will be happy to continue the exchange if you wish, but I don't think this horseflesh is going to get much more tender.
 
Poptech said:
Climate projections: Past performance no guarantee of future skill? (PDF)
(Geophysical Research Letters, Volume 36, Issue 13, July 2009)
- Catherine Reifen, Ralf Toumi

"In our analysis there is no evidence of future prediction skill delivered by past performance-based model selection."
Click to expand...



And if you'd bother to actually read the paper, instead of skimming it for cherries to pick, you'd notice this bit:
We are not implying that comparisons against observations are not important in model validation. Good agreement with past climate builds confidence in the reliability of a model’s future projections. Our analysis only examines selection based on models’ ability to replicate a mean anomaly over a historic time period. There are other criteria that could be used and would be worth investigating.
Click to expand...
 
lomiller said:
Keep in mind that in the case of climate the noise is a product of the chaotic nature of the system so it exists in all realizations, including the real world observations.
Click to expand...

Sure

lomiller said:
PDO is included in the models in two different ways, where it’s known empirically the observed PDO is entered as a parameter. Where it isn’t it’s modeled.
Click to expand...

This is the crux of my question. To model the PDO with any degree of accuracy you need to understand what part of the phase it is in. The three definite PDO phase switches we’ve ‘seen’ were in 1905, 1946 and 1977. That puts the periods at 31 and 41 years. If we assume that the proposed 2008 shift is real then we have a third period of 31 years. That gives us an average of about 34 years and an SD of about 6 years.

Longer term reconstructions seem to point to longer periods but as far as I can tell the data is so polluted with other effects that it’s not particularly valuable.

I can’t even image how one would go about modelling climate when such a significant variable can’t be predicted with any degree of confidence. I guess you could draw probability curves - but I image they’d be so fat they would be near useless anyway?

lomiller said:
The modeled PDO shows the same general characteristics as the observed PDO but can differ significantly for any given year or decade.
Click to expand...

As I would expect.

lomiller said:
Since it’s longer term characteristics are the same, however so the effects drop out of the result past about 20-30 years or so, but for shorter times then that it’s a major contributor to internal variation.
Click to expand...

I’m struggling to understand your point here.

Our understanding of the PDO is so limited that the further out you push your model the less likely it seems that you’ll even know what phase you’re in never mind what part of the cycle you’re in – so in this case longer terms most certainly won’t assist your modelling.

If however, you’re claiming that if the current AGW hypothesis is correct then the magnitude of the change should increase to the point where natural cycles no longer have enough influence to hide the effect, then I agree completely. I do wonder in this case how you’ve decided on the timetable for your ‘window of accuracy’.
 
macdoc said:
I would think the PDO has some significant regional impact even within the last 30 years but I know regional models are still "work in progress".
Click to expand...

I supect the effect might also be global in that in different phases heat moves into and out of the deeper ocean. The total system energy doesn't change but the surface temps do.
 
global warming will certainly mean more women in bikinis.

that..is a very good thing.
 
TShaitanaku said:
I'm not speaking to or about any differences due to changes in the human forcing factors, primarily because I've yet to see that there is or will be significant changes in human actions, at least within the next few decades.
Click to expand...

I too haven't seen the future yet. What I can comfortably predict is that in the next few decades many actions will be performed which would not have been without AGW.

I'm not looking for opinions considering all the potential variations of human action over the next few decades or even centuries. What I was more interested in was the seeming contradiction between the perspective that predictions of effects are so uncertain as to be considered poor science and yet the various science organizations most directly oriented to studying climate change all devote a considerable effort toward providing (and explaining) predictions. But as you say that seems to be an issue that is being left without resolution, so I shall let it lay.
Click to expand...

Prediction aren't considered bad science as long as the uncertainty is properly presented. To be useful in these circumstances science has to make predictions.

Personally, my primary concerns are a bit closer to home.
Click to expand...

As are most people's.

Expanding desertification in the US southwest, storm force increases both coastal and inland, floods in the heartlands, long-term drought in the west. The migration of disease, decrease in viable croplands...the list is actually quite long, and this only goes to the natural impacts that will be being increasingly felt and amplified over the coming decades. Include in the economic and social impacts, and our children's children are inheriting a completely different (and molten) ball of wax.
Click to expand...

A fair amount of disruption seems inevitable. I'm glad I live on the fringe of an island off the fringe of Eurasia.
 
You must log in or register to reply here.

Back
Top Bottom