Merged Global Warming Discussion II: Heated Conversation

[Trakar]

There is no reason winter snows should not increase - there is more moisture in the air and especially with more open ocean additional snow pack would be a given.

Another who shall remain nameless thinks that snow is related to temperature - the colder the more snow....nothing could be further from the truth.

This happens too with a more sodden atmosphere...

I understand the argument and it seems solid, I just haven't seen any compelling supporting evidence for it on a hemispheric or global scale.

 

[Trakar]

Yes, land surface temps certainly aren't about the whole NH, but those studies at least bring some answers about trends in its populated parts.

And, my bad if I haven't understood your reasoning, but doesn't snow cover have the same limitation (i.e. being only about land)? Or is it about albedo?

Albedo is a big part of why the boreal regions get colder than expected.

"Snow cover" only happens on land (ocean ice pack uses different terms), but temperature change happens everywhere. Increases and decreases of snow cover is constant over the same terrain. Increases and decreases of temperature happen everywhere, and it skews the understanding if you say "temps are decreasing over the Northern Hemisphere," when what the evidence indicates, and what you should be saying, is that: "some regions of interior boreal forests, during the winter, are cooling enough due to unexpected events, to offset some of the warming that is occurring throughout the rest of the Northern Hemisphere."

The short version makes a good, if inaccurate sound-byte, the accurate version is conditional, nuanced and requires an understanding of the facts.

 

[CapelDodger]

How does snow affect the amount of water in rivers?
http://www.eurekalert.org/pub_releases/2014-05/uob-hds051614.php

New research has shown for the first time that the amount of water flowing through rivers in snow-affected regions depends significantly on how much of the precipitation falls as snowfall. This means in a warming climate, if less of the precipitation falls as snow, rivers will discharge less water than they currently do.

The study by PhD student Wouter Berghuijs and Dr Ross Woods, Senior Lecturer in Water and Environmental Engineering in the Department of Civil Engineering at the University of Bristol together with a colleague from Delft University of Technology is published online in Nature Climate Change.

The researchers, using historical data from several hundred river basins located across the United States, investigated the effect of snow on the amount of water that rivers discharge.

How river flow is generated in snowy areas is poorly understood due to the difficulty in getting appropriate measurements. Previous studies have mostly focused on the role of snowfall for the within-year distribution of streamflow - how much water is there in the river during a particular period of the year - and assumed that there was no important effect of snow on the average streamflow. This study is the first to focus on the role of snow for how much water is on average available in rivers.

With data from 420 catchments located throughout the United States the researchers show that snowiness is an important factor for the average river discharge.

Global warming is very likely to reduce the amount of snow significantly in snow-affected catchments, even if temperatures rise only two degrees Celsius. The new research suggests that the amount of water in rivers will be reduced as a result of the decrease in snow.

I've only seen the press-release so don't know what the mechanism is, but I suspect something to do with evaporation.

 

[macdoc]

Global warming is very likely to reduce the amount of snow significantly in snow-affected catchments, even if temperatures rise only two degrees Celsius. The new research suggests that the amount of water in rivers will be reduced as a result of the decrease in snow.

I don't think that is given ..a warmer ocean will produce more snow when hitting elevation. I think it will affect distribution of heavier snowfalls but I don't see it reducing.
More moisture in the atmosphere will mean more snow where temperatures are below freezing and there is winds off the water ( lake or ocean ).

If below freezing days reduce then of course less snow but not necessarily less precipitation.
Be interested in the retention tho...could be reduced evaporation - ground will heat up far faster in the sun than snow pack.

 

[CapelDodger]

I don't think that is given ..a warmer ocean will produce more snow when hitting elevation. I think it will affect distribution of heavier snowfalls but I don't see it reducing.

It is just a press-release; perhaps the paper itself refers to the proportion of precipitation which lands as snow. The absolute amount of precipitation is a separate issue.

 

[Garrette]

Need some help, please, because my Google fu is weak, and I have tried it in general and on this thread.

Discussing with an acquaintance elsewhere and mentioned the confidence levels that climate change is anthropogenic. Was asked in return how that confidence level was objectively arrived at. Looking at the IPCC (and commentary on it) yielded their 95% confidence but not any math behind it that I could find. Wider Google searches mostly yielded sites skeptical of the anthropogenic claim, with this one being the clearest I could find.

Am I missing something obvious? Is there a mathematical/statistical chain that leads to the IPCC's (or anyone else's) conclusion that climate change is 95% certain to be anthropogenic?

Thanks

 

[DC]

Need some help, please, because my Google fu is weak, and I have tried it in general and on this thread.

Discussing with an acquaintance elsewhere and mentioned the confidence levels that climate change is anthropogenic. Was asked in return how that confidence level was objectively arrived at. Looking at the IPCC (and commentary on it) yielded their 95% confidence but not any math behind it that I could find. Wider Google searches mostly yielded sites skeptical of the anthropogenic claim, with this one being the clearest I could find.

Am I missing something obvious? Is there a mathematical/statistical chain that leads to the IPCC's (or anyone else's) conclusion that climate change is 95% certain to be anthropogenic?

Thanks

http://www.ipcc.ch/pdf/supporting-material/uncertainty-guidance-note.pdf

 

[Garrette]

Thank you, this helps, but perhaps I am missing something. It leaves open the objection that the 95% confidence stated by the IPCC was not objectively arrived at.

Please note that I am not trying to play gotcha. I'm on the climate change is real and anthropogenic side.

Your link seems like an excellent description of how to rationally synthesize findings like I found on this webpage while waiting for a response, but does not allow me to say that 95% was arrived at objectively.

Perhaps I am simply letting myself be caught in a rhetorical trap? If so, advice on how to escape it would be appreciated, too.

 

[DC]

Thank you, this helps, but perhaps I am missing something. It leaves open the objection that the 95% confidence stated by the IPCC was not objectively arrived at.

Please note that I am not trying to play gotcha. I'm on the climate change is real and anthropogenic side.

Your link seems like an excellent description of how to rationally synthesize findings like I found on this webpage while waiting for a response, but does not allow me to say that 95% was arrived at objectively.

Perhaps I am simply letting myself be caught in a rhetorical trap? If so, advice on how to escape it would be appreciated, too.

it depence what you exactly mean, you can calucalte uncertainties in specific cases, but the overall atribution to CO2 as cause, is a expert judgement.

so no i don0t think it is objectively in those cases, it is expert's judgment.

 

[Garrette]

it depence what you exactly mean, you can calucalte uncertainties in specific cases, but the overall atribution to CO2 as cause, is a expert judgement.

so no i don0t think it is objectively in those cases, it is expert's judgment.

Okay. So I have to avoid the rhetorical trap. I think I can do that, but we'll see.

Cheers.

 

[Trakar]

it depence what you exactly mean, you can calucalte uncertainties in specific cases, but the overall atribution to CO2 as cause, is a expert judgement.

so no i don0t think it is objectively in those cases, it is expert's judgment.

Actually, it is an experimentally confirmed result that CO2 is a greenhouse gas, therefore increasing concentrations of it will result in a warming of the atmosphere. Likewise, shifting isotopic concentrations of atmospheric CO2consistent with isotopic ratios of sampled coal, oil, and gas resources and with the business records of such resource recovery confirm to sourcing of the rising atmospheric concentrations of CO2. Expert judgment acknowledges and operates in accordance with these facts, but it seems backwards to simply say that the support is due to the expert acceptance rather than that expert acceptance is due to the understanding and verifiable nature of the facts which lead to the expert acceptance.

Once you start down the road of laying off the findings of science on the "subjective opinions of experts" it is a short step to dismissing such by developing the mindset that science is all about the subjective opinions "experts." Most pseudoscience paths are all about finding other experts that say things you find more convenient to the other opinions groups of people prefer about how the world should work. A big part of science, is going where all the evidences lead you.

 

[DC]

Actually, it is an experimentally confirmed result that CO2 is a greenhouse gas, therefore increasing concentrations of it will result in a warming of the atmosphere. Likewise, shifting isotopic concentrations of atmospheric CO2consistent with isotopic ratios of sampled coal, oil, and gas resources and with the business records of such resource recovery confirm to sourcing of the rising atmospheric concentrations of CO2. Expert judgment acknowledges and operates in accordance with these facts, but it seems backwards to simply say that the support is due to the expert acceptance rather than that expert acceptance is due to the understanding and verifiable nature of the facts which lead to the expert acceptance.

Once you start down the road of laying off the findings of science on the "subjective opinions of experts" it is a short step to dismissing such by developing the mindset that science is all about the subjective opinions "experts." Most pseudoscience paths are all about finding other experts that say things you find more convenient to the other opinions groups of people prefer about how the world should work. A big part of science, is going where all the evidences lead you.

sure those are the basics on which (and much much more) experts base their assesment on.
but there is no objective measurements of single forcings. the quantifications of the forcings are not realy measured . but we need to "estimate" how much the contribution of CO2 is. so there is some uncertainty we canot precisely quantify.

this in no way means their assesment is not better than Lord Monckton's ^^
it is the best assesment we have. it is what we have to go by. it is our best knowledge.

 

[Trakar]

Thank you, this helps, but perhaps I am missing something. It leaves open the objection that the 95% confidence stated by the IPCC was not objectively arrived at.

Please note that I am not trying to play gotcha. I'm on the climate change is real and anthropogenic side.

Your link seems like an excellent description of how to rationally synthesize findings like I found on this webpage while waiting for a response, but does not allow me to say that 95% was arrived at objectively.

Perhaps I am simply letting myself be caught in a rhetorical trap? If so, advice on how to escape it would be appreciated, too.

It is important to remember that the IPCC does not do actual scientific research, they do literature reviews of published science. The confidence levels in IPCC aren't assessments of the actual facts so much as they are quantifications of the levels of support and confirmation that the lead authors (authoring groups) find among existent scientific understandings and current journal publications for particular concepts that are examined in relation to climate science and climate observations.

 

[lomiller]

Need some help, please, because my Google fu is weak, and I have tried it in general and on this thread.

Discussing with an acquaintance elsewhere and mentioned the confidence levels that climate change is anthropogenic. Was asked in return how that confidence level was objectively arrived at. Looking at the IPCC (and commentary on it) yielded their 95% confidence but not any math behind it that I could find. Wider Google searches mostly yielded sites skeptical of the anthropogenic claim, with this one being the clearest I could find.

Am I missing something obvious? Is there a mathematical/statistical chain that leads to the IPCC's (or anyone else's) conclusion that climate change is 95% certain to be anthropogenic?

Thanks

There are two separate issues here.
1) How the total heat energy trapped within the earth’s atmosphere/ocean is changing
2) How the distribution of the heat energy trapped within the earths atmosphere/ocean is changing.

Regional projections are important for determination consequences of global warming but there is a lot more uncertainly in them than in the overall global trend because figuring out the distribution of energy in the atmosphere is a MUCH more difficult question with wider error margins than figuring out how total energy will change. This is why you see a lot of denier smoke screens based on cherry picking a region or short period of time.

Rhetorically the best way to deal with someone cherry picking a region is to emphasize the global part of global warming. Pointing to total heat content numbers can also prove useful depending on your audience, but they can come off as a little complex for some.

 

[CapelDodger]

it depence what you exactly mean, you can calucalte uncertainties in specific cases, but the overall atribution to CO2 as cause, is a expert judgement.

A consensus opinion, in other words.

 

[a_unique_person]

Actually, it is an experimentally confirmed result that CO2 is a greenhouse gas, therefore increasing concentrations of it will result in a warming of the atmosphere. Likewise, shifting isotopic concentrations of atmospheric CO2consistent with isotopic ratios of sampled coal, oil, and gas resources and with the business records of such resource recovery confirm to sourcing of the rising atmospheric concentrations of CO2. Expert judgment acknowledges and operates in accordance with these facts, but it seems backwards to simply say that the support is due to the expert acceptance rather than that expert acceptance is due to the understanding and verifiable nature of the facts which lead to the expert acceptance.

Once you start down the road of laying off the findings of science on the "subjective opinions of experts" it is a short step to dismissing such by developing the mindset that science is all about the subjective opinions "experts." Most pseudoscience paths are all about finding other experts that say things you find more convenient to the other opinions groups of people prefer about how the world should work. A big part of science, is going where all the evidences lead you.

People seem to demand that the scientists give a perfect prediction from complete understanding. That's not going to happen.

We didn't have economists giving us a prediction of the Global Financial Crises, yet they still have jobs and we still live with Capitalism. Sometimes imperfect knowledge is the best we have on which to base our decisions.

 

[AlBell]

A consensus opinion, in other words.

I.E. Politics.

 

[Trakar]

I.E. Politics.

No, politics is the process of instituting public policy. Consensus is merely an agreement on some specific common understandings. The problem with most politics is that there is no semblance of consensus, nor even the need to develop such.

 

[Trakar]

People seem to demand that the scientists give a perfect prediction from complete understanding. That's not going to happen.

We didn't have economists giving us a prediction of the Global Financial Crises, yet they still have jobs and we still live with Capitalism. Sometimes imperfect knowledge is the best we have on which to base our decisions.

No knowledge is perfect. There is always an element of uncertainty.

 

[AlBell]

No, politics is the process of instituting public policy.

Yup, just what warmers are struggling to do.

Consensus is merely an agreement on some specific common understandings. The problem with most politics is that there is no semblance of consensus, nor even the need to develop such.

Voting makes a difference, or at least should, in theory.