THE UNOFFICIAL OFFICIAL GLOBAL WARMING THREAD

[Patrick Marsh]

The global warming thread to end all global warming threads.

*sarcasm* Flame away...



Mods: Please feel free to delete if you feel this is out of line.

 

[Patrick Marsh]

In all serious, if we keep all the GW talk in this thread then people not wishing to engage can just avoid one thread. This will also allow mods to moderate this topic a little easier. If they don't have 20 threads on GW going, they can keep up with the tone a lot easier and hopefully won't be so sick of it.

As was brought up in another thread, I am currently working on climate change and impacts on severe storms. I will be more than willing to discuss the scientific merits of this research, but I will not engage in a flame war. I welcome criticism as it allows me to strengthen my research; I believe this is the way science was meant to work anyways.

 

[Aaron Kennedy]

How well do you feel proxies such as CAPE*shear can approximate the climatic change of severe storm climatology? The only thing I feel we have *nailed* down in GCMs are greenhouse gas feedbacks (dominate forcing) and the atmospheric dynamics. What say thee about our uncertainties in clouds/aerosols?

Given that storms are often the result of mesoscale conditions/circulations, and that these other feedback processes can be important for regional climate change, do we have any hope in approximating the climatic change in events which are considered rare (tornadoes, supercells, etc.)?

While I think it's easy to say these events can either increase/decrease, attaching a numerical quantity to these figures is tough. What sort of change are we talking about? An extra "event" a year or more?

Then again, how much faith should we have in GCMs which use simplified parameterizations (a necessity) for microphysics and predicting cloud? If XXX model run in single-column mode misses upwards of 50% of clouds above 6km at a mid-latitude continental location, yet still achieves the right radiation balance, can we trust calculations of variables that determine our proxies for severe storms?

I sound pretty cynical, but these are questions we need to answer to make GCMs more accurate.

 

[Dustin Wilcox]

Anyone doing any research involving Climate change and its impacts on upper level temperatures? I hear an awful lot regarding warmer surface temps leading to higher moisture content and ultimately stronger storms, but what is the correlation between change in surface temps versus change in upper level temps, does Climate Change have a > or < impact on upper atmospheric temperatures versus surface temps. While folks fret over > srfc temps and moisture content leading to more frequent and violent storms couldn’t exactly the opposite occur if upper level temps are indeed increasing more so then srfc temps, ultimately leading to lower lapse rates and a stronger capping inversion.

 

[Patrick Marsh]

Dustin,

Just saw your post and wanted to make sure I understood what you were asking. By upper-level temps are you still talking about troposphere? I would assume you were, but when dealing with climate change most climate scientists think stratosphere when talking about upper level temps.

As for your post Aaron, I'll post a response tomorrow some time. I just got back in from a week long conference and am a little tired at the moment.

 

[Dustin Wilcox]

Dustin,

Just saw your post and wanted to make sure I understood what you were asking. By upper-level temps are you still talking about troposphere? I would assume you were, but when dealing with climate change most climate scientists think stratosphere when talking about upper level temps.

I'm strictly focusing on the troposphere given this is the environment in which our storms occur, according to climate scientists, is current forecast climate change predicted to have a universal affect on the Troposphere or are different heights within the troposphere expected to experience varying degrees of change? This variable could greatly alter the frequency and strength of storms if climate change is indeed altering different levels of the troposphere at varying levels.

 

[Shane Adams]

I vote for the Death Penalty for anyone who starts this thread again.

 

[Doug Lee]

Enough!

I've held off from commenting on this issue because I want to get my thoughts organized and check out some things first.

I will say that these discussions do remind me of this.

 

[Patrick Marsh]

Aaron,

Don't worry about being cynical. This is a tough problem and their are many days where I am cynical.

I personally think that with the current state of AOGCMs there is absolutely no chance of making a prediction about how climate change will impact severe thunderstorms. Horizontal resolution is on the order of greater than 1.5 degrees in both latitude and longitude and around 12 vertical levels in the troposphere in the highest resolution models used in the IPCC AR4. However, this resolution is close enough to begin examining mesoscale environments.

I think that the best approach in examining these environments is to compare the statistics of the AOGCMs to the statistics of the NCAR / NCEP Global Reanalysis (which is of similar horizontal resolution). Using this approach, I agree that it is fairly easy to say the number of environments favorable for severe weather will increase or decrease (using the methodology set forth by Brooks et al. 2003). However, I feel it is impossible to quantify the number of events per year. Why? Because there is no way of examining initiation at such course resolution. In other words, there is absolutely no way of knowing if these environments are ever realized.

You question whether we should have much faith in the GCMs that use simplified parameterization schemes and I have the same questions. In fact, in my masters thesis, I included the disclaimer saying that everything is contingent on accepting the CCSM3 GCM as reasonable, but that it was a different paper altogether to discuss whether this assumption is true. I know for a fact that the CCSM3 (from NCAR) has problems generating any mesoscale CAPE. It is almost all synoptically driven (i.e., when a synoptic scale system is moving through) and there is very little CAPE generated in the high plains in the summer when every day you get ~1000 J/kg just due to evapotranspiration and daytime heating (indicating a land-model problem). The models are tuned to creating tropical CAPE which is the most prevalent in a global sense, but almost worthless for severe storms.

These are difficult questions. But by no means do I think this means we should give up. I do think it means we can't say anything definitive in regards to severe storms and climate change, a stand I wish more people in this arena would take. This is all preliminary work, but overall it's fairly consistent in the models that CAPE greatly increases and that 0-6km shear decreases very slightly. The million dollar question is will the balance of the two that works now still work in the future.

I am in the process of downscaling climate models to regional models with the WRF in hopes of taking advantage of the better physics schemes. The results are very encouraging so far. but there is a long ways to go.

 

[Dave Gallaher]

Okay -
At the risk of being deleted again, or sentenced to death, here is the article I wrongly placed in the 'thread thread' a few days back:

10/22/2007
by Randolph E. Schmid
The Associated Press

CARBON DIOXIDE IN ATMOSPHERE INCREASING

WASHINGTON (AP)

Just days after the Nobel prize was awarded for global warming work, an alarming new study finds that carbon dioxide in the atmosphere is increasing faster than expected.

Carbon dioxide emissions were 35% higher in 2006 than in 1990, a much faster growth rate than expected, researchers led by Josep G. Canadell, of Australia's Commonwealth Scientific and Industrial Research Organization, report in Tuesday's edition of Proceedings of the National Academy of Sciences.

Increased industrial use of fossil fuels coupled with a decline in the gas absorbed by the oceans and land were listed as causes of the increase.
"In addition to global population and wealth, we now know that significant contributions to the growth of atmospheric CO2 arise from the slowdown" of nature's ability to take the chemical out of the air, said Canadell, director of the Global Carbon Project at the research organization.

......

Continue reading the rest of the article HERE

 

[Ben Baranowski]

It's been awhile since I went through this article, so I can't remember if it contradicts Dave's above, but it definitely is good accompaniment reading.

http://realclimate.org/index.php?s=...A55;GIMP:66AA55;FORID:11;&searchdatabase=site

I think articles like these start to illustrate the complexity in the science and data set used. Everybody (especially those with little knowledge of climate science) need to make sure they're talking about the same things.

Ben

 

[Dave Gallaher]

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D20109, doi:10.1029/2006JD008345, 2007
Telescoping, multimodel approaches to evaluate extreme convective weather under future climates

Scott,
I am by no means a scientist, but I think I get the drift of the first quote. However, I have read the second one several times and am still uncertain that I understand the ramifications mentioned, beyond one testing method being more dependable than another. Can you break this down a little?

Thanks.

 

[Doug_Kiesling]

Oh yeah, in my global warming update, yesterday and this morning, I had to let my Big Bad SUV sit and run for over 15 minutes while wasting at fuel... all to warm up before I could drive it since the OAT was -7F in St. Cloud, MN yesterday and -4 this morning.

Wow, if you think about it, Global Cooling Kills. I lost track at the number of people killed in the last 6 weeks from the snow and ice storms. What is it, 11 dead just from the latest round of ice storms?

 

[JF Massicotte]

Hey guys:

http://news.independent.co.uk/sci_tech/article3223603.ece


Global temps going down? Trend is -0.5 C this year. I don't understand, I changed my fuel efficient sedan for a big SUV.... shouldn't temps go up?