Of Climate Models and Hurricane Predictions

[Phil153]

BT,

Your question is a complex one and the subject of an entire IPCC report involving years of research from some of the world's best think tanks.

At the end of the reckoning the EV equation is very solidly in the realm of there being a significant net damage to economies, and mitigation being +EV overall. See here for example (I strongly encourage anyone to read the actual reports if they're interested in the topic):

http://en.wikipedia.org/wiki/Economi...global_warming

[Phil153]

The hurricane thing is dumb. Just because I can't predict whether it'll rain over your house next Tuesday doesn't mean I can't predict the effects of increasing water vapor concentration on Mars. Some things are physically well understood, others are not.

And the hurricane models are probability models and their failure doesn't even reach statistical significance by the looks of it. Hurricanes are highly chaotic systems whose formation can never be more than a probability model, whereas the CO2-heat retention link is very simple and well observed physics.

I have a question for Wacki though. Since we all gamble...what odds would you give me on temperatures increasing by at least 2 degrees within 50 years?

[wacki]

[ QUOTE ]
The hurricane thing is dumb. Just because I can't predict whether it'll rain over your house next Tuesday doesn't mean I can't predict the effects of increasing water vapor concentration on Mars. Some things are physically well understood, others are not.

And the hurricane models are probability models and their failure doesn't even reach statistical significance by the looks of it. Hurricanes are highly chaotic systems whose formation can never be more than a probability model, whereas the CO2-heat retention link is very simple and well observed physics.

I have a question for Wacki though. Since we all gamble...what odds would you give me on temperatures increasing by at least 2 degrees within 50 years?

[/ QUOTE ]

Nice post and one I've tried to make but didn't do very well when it comes to laymen terms (I merely talked about spatial resolution and designed purpose). As for your question do you mean 2 degrees C or F? And from with starting point today? I'm not familiar with 50 year projections only 100 year and beyond so I'd have to do a little reading.

So much depends on the human element as well. Many people believe the next presidential term is going to be so critical. Global economy, research initiatives, wars and peak oil are all going to be huge wild cards. There is a book I'm extremely eager to read and has gotten excellent reviews in Nature and Realclimate:
http://www.amazon.com/Six-Degrees-Future...2656&sr=8-3

This layman friendly review of 500 journal articles should be an excellent guide to understand how bad this situation might get.

[Phil153]

Celsius, starting from current avg temperatures over the recent period.

I'm aware of the 100 year predictions. You've done a lot of reading and I wanted to get your feel on the likelihood of high-medium to catastrophic warming in the coming decades, which the science shows as plausible (and lower probability), but the reports deliberately shy away from for political reasons.

[wacki]

Well current glacial trends on the other side of the planet show that they are going to face some really tough water problems. Glacier trends show that with overwhelming evidence. The ocean is showing signs that it has saturated.

http://www.pnas.org/cgi/reprint/0702737104v1

The Co2 Growth rate in the atmosphere is almost triple of what it was in the 1990s. Ocean acidification could occur sooner than expected as well. A lot of things have developed that I'm not sure have been included in the AR4.

This is the 2001 IPCC projection:
http://www.ipcc.ch/graphics/graphics...arge/05.02.jpg

AR4's (more accurate) projections are here:
http://www.ipcc.ch/graphics/graphics...t/figure10.ppt

Basically the projections are showing that temps will be a little bit under 2 degrees C in 50 years (there is overlap above 2 degrees C depending on emissions scenario). However recent developments such as ocean saturation has been less than comforting. Good new is that the planet has a lot of inertia so 30-50 years out is considered rather easy to ppredict as CO2 doesn't matter too much. Albedo another story as ice melt is not looking fun either. Things may have changed though I simply don't know. At this moment I'm willing to say 2 degrees C is unlikely in 50 years but again things may change.

[Kaj]

[ QUOTE ]
The hurricane thing is dumb. Just because I can't predict whether it'll rain over your house next Tuesday doesn't mean I can't predict the effects of increasing water vapor concentration on Mars. Some things are physically well understood, others are not.

And the hurricane models are probability models and their failure doesn't even reach statistical significance by the looks of it. Hurricanes are highly chaotic systems whose formation can never be more than a probability model, whereas the CO2-heat retention link is very simple and well observed physics.

[/ QUOTE ]

Excellent post. I know several people who believe along the lines "we can't even predict the waether, how can we predict global warming".

[Jcrew]

[ QUOTE ]
These results indicate that the range of uncertainty in anthropogenic forcing of the past century is as large as the uncertainty in climate sensitivity and that much of forcing uncertainty is due to aerosols.

[/ QUOTE ]


Jeffrey T. Kiehl, 2007. Twentieth century climate model response and climate sensitivity. GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L22710, doi:10.1029/2007GL031383, 2007