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Fraser
2005-Nov-02, 03:50 AM
SUMMARY: Scientists at the Lawrence Livermore National Laboratory have developed a detailed model of the Earth's climate over the next few centuries to answer the question... what if we burned all the fossil fuels by the year 2300. The answer, of course, isn't a pretty picture. In their model, global temperatures will rise 8-degrees Celsius (14.5 F), and melting polar caps will raise the oceans 7 metres (23 feet). The damage would be even worse in the polar regions, which could grow by 20-degrees C (68 F).

View full article (http://www.universetoday.com/am/publish/world_8_degrees_hotter.html)
What do you think about this story? post your comments below.

Joff
2005-Nov-02, 04:19 AM
Well, that's all my respect for Lawrence Livermore gone - can't they even write chemical formulas? CO2 not CO2 !! :lol:

Seriously the temperature rise is less than I expected - perhaps the result of spreading the fuel burning over another 300 years - but the sea level rise is way more than I expected, although if Antartica and Greenland melt it's believable I guess.

cran
2005-Nov-02, 01:49 PM
hmm ... I vaguely recall similar articles a few years back, with pretty much the same results, or conclusions ...
still, a model is a model ... it's results are only as good as the data and rules it is given...

Joff
2005-Nov-02, 02:54 PM
still, a model is a model ... its results are only as good as the data and rules it is given...So, Cran, do you think that the data is inadequate for the predictions being made, or the modelling process (to generalise "rules"), or both? Or are you just making woolly noises to avoid commiting to the conclusions of the model? Or what would help you understand the level of uncertainty?

cran
2005-Nov-02, 05:21 PM
So, Cran, do you think that the data is inadequate for the predictions being made, No ... and yes; I expect that the predictions being made are entirely consistent with the data put into the model, and the processes, parameters, etc (the 'rules') which govern the model(s) being applied, therefore 'no' ... ;
the data includes an estimate (or more probably, a range of estimates) of the amount of fossil fuels which can be extracted and/or burnt - and in geological resource estimates, there is a substantial difference between 'proven reserves' and 'probable resources', and an even larger difference compared with 'estimated resources' - each of which has its own 'cut-off grade' (level of resource to impurities, below which extraction is considered uneconomic), and that estimate range may or may not include an estimate of undiscovered fields, and potential improvements to extraction and processing, therefore 'yes'...

or the modelling process (to generalise "rules"), yes, though they are becoming more sophisticated (able to incorporate more variables), they are still based on a number of "if x, then y; if not x, then z" conditions, and how each 'y' and 'z' are determined may or may not include estimates or assumptions which are neither implicit nor explicit in their framing; this particular model may or may not take into account inputs from non-fossil fuel resources (eg accelerated deforestation, and/or biomass combustion) and other potential feedback or regulatory responses from the environment ...

or both? can't give the same answer for both (see above)

Or are you just making woolly noises to avoid commiting to the conclusions of the model? What does this mean? Are you simply being rude? Are you implying that I should commit to the conclusions of the model?

Or what would help you understand the level of uncertainty? If you're asking what don't I know ... that would fill libraries ...

eoleen
2005-Nov-02, 07:36 PM
I've got to question their model. For one thing, there are at least 65 meters of sea-level rise locked up as ice in the Antarctic IceCap (private communication with Robert Bindschadler of NASA - a specialist on the ice cap). Secondly, I see no mention of the methane clathrate time bomb: the bottom of the actic (and other?) ocean is covered with methane locked up in ice: the form is called methane clathrate, and it seems to be near the point of releasing the methane. Methane is several times as effective as carbon dioxide as a green-house gas.

And I don't think it'll take as long as LLNL suggests: positive feedback reactions go to completion in a remarkably short time. Look at the Larson B ice shelf, the size of Rhode Island, which broke up in something like a month.

Joff
2005-Nov-02, 08:20 PM
Thanks for your detailed answers cran... I felt I had to challenge your original answer as it's the kind of response that is sometimes used to dismiss predictions, without much regard of how accurate they are, just on the basis that there is some imprecision somewhere.

You had one major query in common with me - where did the figure for the amount of fossil fuel come from? I'm thinking that the bulk of that figure came from coal reserves, plus known oil/gas reserves.


they are still based on a number of "if x, then y; if not x, then z" conditionsI agree that there will be relationships determining subsequent state compared to previous conditions and ongoing inputs, but it will be more "fuzzy" than simple flip states and multi-parametered for each of many cells across the globe and many time steps along the model.


...estimates or assumptions which are neither implicit nor explicit in their framingGood trick... you'll have to teach me that one ;)


...accelerated deforestation, biomass combustionI think they weren't taking deforestation into the model. Biomass combustion without deforestation should balance.


Are you simply being rude?Not really. Blunt perhaps. I was just laying out the alternatives. I wasn't sure if you'd thought about what the phrase you used meant or not.


If you're asking what don't I know ... that would fill libraries ...Join the club :lol:

cran
2005-Nov-02, 10:53 PM
Thanks for your detailed answers cran... I felt I had to challenge your original answer as it's the kind of response that is sometimes used to dismiss predictions, without much regard of how accurate they are, just on the basis that there is some imprecision somewhere. Fair enough; I do tend to throw in the 'hmmm' factor where results from models are published and held up as anything more than results from models - especially if only one set of results is indicated.

You had one major query in common with me - where did the figure for the amount of fossil fuel come from? I'm thinking that the bulk of that figure came from coal reserves, plus known oil/gas reserves.Yes, and whether or not it included shale oils, so the potential might be quite a bit higher.



Originally Posted by cran they are still based on a number of "if x, then y; if not x, then z" conditions
I agree that there will be relationships determining subsequent state compared to previous conditions and ongoing inputs, but it will be more "fuzzy" than simple flip states and multi-parametered for each of many cells across the globe and many time steps along the model. Granted, I used the simplest example.



Originally Posted by cran ...estimates or assumptions which are neither implicit nor explicit in their framing Good trick... you'll have to teach me that one ;) An example, in modelling groundwater flow, a number of conditions are assumed so that the model can work - some of the most common are 'infinite in extent' (if an unbounded system) or 'simplified geometry' (if a bounded system) , 'homogeneity and isotropy of the aquifer' (in the simplest models - one or both may be factored in as variables in more complex models), 'steady-state over time' (ie, inputs equals outputs - no natural change in storage or hydraulic pressure), and 'all significant factors are known or estimated' (any unknowns are therefore insignificant) - any or all of these may not apply to the reality being modelled; likewise, not all of these assumptions will necessarily be included in the report of findings, and may not be implied in the result

In the model under discussion, such assumptions may include 'no change to average atmospheric density', 'no change to global weather or ocean circulation patterns', 'no change to carbon sink responses or capacities', 'no change to population patterns or trends', 'no change to deforestation or desertification trends', 'no change to methane clathrates volumes or status', 'no change to tectonic activity rates'... and possibly a hundred other things - OR, some or all of these may be factored in as a range of estimates, in which case, each one is a variable, and the final results should reflect the range of possibilities thus generated.
But, closer to home, even the simplest things include assumptions that may not be immediately obvious - telling your friend, "I'll talk to you tomorrow" includes the assumption that neither of you will be in a position where that may not be possible (and the possibilities range from not having the time to spare tomorrow, to a simple case of laryngitis, to something more drastic).

I think they weren't taking deforestation into the model. Biomass combustion without deforestation should balance. In which case, the results may be underestimated - the combination of effects from increasing temperatures, changes to cloud formation and precipitation/electrical storm activity, decreasing fossil fuel reserves, and increasing fuel biomass production, would suggest an acceleration of deforestation, I think.


Not really. Blunt perhaps. I was just laying out the alternatives. I wasn't sure if you'd thought about what the phrase you used meant or not. Fair enough. Yes, I thought about it.


Join the club :lol: A card-carrying charter member. :D

cran
2005-Nov-02, 10:58 PM
I've got to question their model. For one thing, there are at least 65 meters of sea-level rise locked up as ice in the Antarctic IceCap (private communication with Robert Bindschadler of NASA - a specialist on the ice cap). Secondly, I see no mention of the methane clathrate time bomb: the bottom of the actic (and other?) ocean is covered with methane locked up in ice: the form is called methane clathrate, and it seems to be near the point of releasing the methane. Methane is several times as effective as carbon dioxide as a green-house gas.

And I don't think it'll take as long as LLNL suggests: positive feedback reactions go to completion in a remarkably short time. Look at the Larson B ice shelf, the size of Rhode Island, which broke up in something like a month. Sorry for not acknowledging your post before, eoleen, or your point about clathrates - caught up in the 'back & forth' with Joff. :o

ToSeek
2005-Nov-03, 01:36 AM
My hope is that we'll be off our addiction to burning hydrocarbons in another few decades.

Joff
2005-Nov-03, 03:31 AM
I've got to question their model. Go for it!:dance:

For one thing, there are at least 65 meters of sea-level rise locked up as ice in the Antarctic IceCapQuite possibly, given an average ice-cover of about 2km. However a twenty-degree rise in temperature won't actually bring the temperature above freezing at the Pole from present-day values. I doubt we'd see anything like a complete melt in the timescale of the model. Not to say that things won't get worse thereafter.

Secondly, I see no mention of the methane clathrate time bomb... it seems to be near the point of releasing the methane. Methane is several times as effective as carbon dioxide as a green-house gas.Nobody seems to have decided what temperature the methyl hydrates will outgas at... if you know, tell us!

Positive feedback reactions go to completion in a remarkably short time. Look at the Larson B ice shelf, the size of Rhode Island, which broke up in something like a month.There is positive feedback (eg. reduction of ice-cover) and negative feedback (eg. increased cloud cover), and I'm sure that both will have been modelled as well as possible in this study. These and many others are recognised components of climate study and prediction.

cran
2005-Nov-03, 05:42 AM
My hope is that we'll be off our addiction to burning hydrocarbons in another few decades. I'm counting on it ... otherwise, we will be forced to go "cold turkey" ... or should that be "roast turkey"? :sick:

SolusLupus
2005-Nov-03, 06:27 AM
There's a lot more involved in burning up all our fossil fuels than merely having a hotter climate. Global warming is bad, yeah, but so would a complete and total shift of economy.

A LOT relies on fossil fuels - from plastics to industry. Without fossil fuels, a lot of industry would come to a dead stop. The economic impact is immense. Some people claim it might lead to the next depression.

Not sure on that one, personally, I don't have all the facts and I haven't studied economy all that much, but it's still food for thought.

ArgoNavis
2005-Nov-03, 10:23 AM
A LOT relies on fossil fuels - from plastics to industry. Without fossil fuels, a lot of industry would come to a dead stop. The economic impact is immense. Some people claim it might lead to the next depression.


Depression? Try end of civilisation as we know it. The world may not be able to support 9 or so billion at the US standard of living, but it sure couldn't support that many as hunter gatherers. The only alternative is the future is probably more optimistic than than, markets will adjust and people will adapt. And there is always problems in extrapolating the current trends, a la Club of Rome.

Doesn't mean that some attempt shouldn't be encouraged to develop new technologies.

SolusLupus
2005-Nov-03, 11:36 AM
I don't think you get it, ArgoNavis. I'm actually making the assumption that we switch from gasoline into another power with vehicles.

What I'm mainly saying is, fossil fuels mean a LOT more than just moving your car around. It's a major product of a lot of companies, many of which don't have to do with vehicles. I'm not sure how far-reaching fossil fuels are, though - anyone care to make a list?

cran
2005-Nov-03, 12:44 PM
plastics - ubiquitous
lubricants - common
non-aqueous coolants/thermal regulators - common
road construction additives - widespread
... ?

JESMKS
2005-Nov-03, 05:41 PM
The rise and decline of civilization on Easter Island is the story that will probably be repeated in a larger scale on Earth. The population of this isolated island may have peaked at about 20,000. The once lush forests were eventually consumed and the civilization decayed into civil war and near extinction. Not a pleasant prospect.
Jack

Joff
2005-Nov-03, 07:41 PM
What I'm mainly saying is, fossil fuels mean a LOT more than just moving your car around. It's a major product of a lot of companies, many of which don't have to do with vehicles. I'm not sure how far-reaching fossil fuels are, though - anyone care to make a list?Strictly it's only fuel if you're using it to release energy; plastics and other chemical industries are therefore using the same substance for a different purpose. However they may well be impacted if there is no fuel market to make oil and gas extraction economic at todays prices.

Obviously other vehicles use fossil hydrocarbons as fuel too; aeroplanes are extremely hungry users of fuel relative to payload kg/km, cars middling, ships relatively economical.

I don't really think that the shift in the economy needs to be huge, athough no doubt there wil be transition pain; once main power generation can be achieved without fossil carbon sources, the extra required to service transport is not orders of magnitude different.

unixobject
2005-Nov-05, 04:05 AM
As i understand it a lot of the banks products are backed up with oil stock as its been a pretty sure bet for a long time, which is how they afford to pay you interest etc, they invest at least some of your money in oil stock. if oil stock crashed who knows what would happen.

also there is a thing called "peak oil theory" which makes some pretty interesting reading about life after oil, http://www.lifeaftertheoilcrash.net/
or just google for "peak oil theory"

another point made is that if civilization did crash - not saying it will but if it did - then think about it, there may not be a second chance to get to the stars and the like, we've dug up all the easily available resources, iron/coal/gas/oil etc etc, so future people will have to find other ways to power their lives, which could be difficult to do when you haven't got any power to research with. Sure its an extreme example but food for thought.