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Another milder-than-normal season takes shape

During the active 2005 hurricane season, the usual doom-and-gloom prophets blamed the storms on global warming. "Nature's wrath," we were told, "hath been unleashed". Aided by a complaisant media, we were told this was our wakeup call, come to punish us for our SUV-driving ways.

Then disaster struck.  The 2006 season not only didn't live up to predictions, it wound up being one of the quietest seasons of the past century. No matter. We were told to ignore this year-long blip, told that 2007 would come roaring back with a vengeance.

And yet, here we are, two full months into the season, and not a single hurricane has formed. Not one. Just two mild tropical storms, one of which didn't even strike land, and a third storm which never went above subtropical status. Hurricane forecasters are busily downgrading their predictions for the rest of the season.

And so it goes. The sky isn't falling yet. But what about the future? Will global warming wreck all our beach-going vacations?

There are two schools of thought regarding the effects of climate change on hurricane science. The first begins with the fact that hurricanes require warm water to form. Global warming means warmer water, leading to the naive conclusion is that more hurricanes will form. The second school realizes that hurricanes are heat engines -- driven not by raw temperature, but by temperature differentials between regions. Global warming warms the arctic and temperate belts, but not the tropics. This reduces the total energy available for major storm formation. It also increases upper-level wind shear, which tends to tear apart storms before they grow too strong. This school believes the long term effects of global warming will be fewer, milder storms.

Climate change aside, hurricanes come and go in cycles. Professor William Gray, one of the nation's most respected hurricane forecasters, believes storm activity will remain high for the next several years, due simply to a long-term cycle of changing Atlantic currents. A team of researchers led by Dr. Chris Landsea of the National Hurricane Center goes further. In a paper published last year, they claim storm rates have not risen over the past 100 years, but only that improved monitoring technology results in registering storms which would have previously been missed. And professors Vecchi and Soden's research on wind shear suggests no long-term storm activity increase should be expected.

I don't know about the rest of you, but I'm not selling my ocean-front condo just yet.


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RE: Here's the reference...
By masher2 (blog) on 7/31/2007 4:25:42 PM , Rating: 1
> "The suggestion that solar output changes are driving global warming has been largely debunked..."

No. The link isn't based on direct solar output (e.g. direct radiative forcing, which indeed does not fully explain climate change) but rather solar activity. Changes in the heliosphere reduce cosmic ray flux, which acts to reduce cloud cover. According to Svensmark's research, this factor acts to amplify radiative forcing by up to a factor of four.

The research of Svensmark and the Danish Space Center has not been refuted.


RE: Here's the reference...
By Rovemelt on 7/31/2007 5:25:16 PM , Rating: 1
I understand that solar activity regulates cosmic ray flux, which is linked to cloud formation. However, there's no trend in the cosmic ray record from the 50's to now that can explain the recent warming. The article I linked to points out in the graphs large changes in cosmic ray count, but a steady warming of the earth.

Svensmark also had to revamp his theory after it was found that he used an incomplete cloud cover model. That's when he switched to a low cloud cover model. It seems like he's grasping onto this model and the more he uses it, the weaker the correlation.

The findings of Svensmark have been very controversial because there seems to be little link between cosmic rays and warming over the past 50 years, but difficult to assess as cloud formation remains difficult to model. From what I've read, the majority of climatologists just don't see cosmic rays accounting for the bulk of the recent change. Moreover, if cosmic rays were playing such a strong role, why are nighttime warming trends greater than daytime warming trends? Those two discrepancies put major holes in Svensmark's work, and he's going to have to pull some amazing research stunts to get around those.

Still, I have no doubt that cloud formation research needs to continue to improve climate models.

Here is a link to a Discover magazine interview with Svensmark. You should see what he says:

http://discovermagazine.com/2007/jul/the-discover-...

quote:
Do you agree that carbon dioxide is having at least some impact on Earth’s current warming?

Yes, but you have to give the sun a role. If you include the sun in the right way, the effect of CO2 must be smaller. The question is, how much smaller? All we know about the effect of CO2 is really based on climate models that predict how climate should be in 50 to 100 years, and these climate models cannot actually model clouds at all, so they are really poor. When you look at them, the models are off by many hundreds percent. It’s a well-known fact that clouds are the major uncertainty in any climate model. So the tools that we are using to make these predictions are not actually very good.

Do you think then that individuals and societies as a whole need to try to conserve energy? Do you use compact fluorescent lightbulbs, for instance?

Yes, yes, we use those. And I ride a bicycle. There are good reasons to conserve our resources and find a more economical way of using energy, but the argumentation is not linked necessarily to climate.


Even Svensmark is using caution here.


RE: Here's the reference...
By masher2 (blog) on 7/31/2007 5:48:45 PM , Rating: 2
Svensmark's "caution" is that he says there are good reasons to be efficient in our use of energy, reasons that have nothing to do with climate change. But he clearly and emphatically states that solar activity is the primary driver of climate change, not anthropogenic effects.

> "if cosmic rays were playing such a strong role, why are nighttime warming trends greater than daytime warming trends? "

Heavy cloud cover retains heat; this is pretty basic, and not disputed by anyone. Clouds are water vapor, a much stronger greenhouse gas than CO2.

In fact, this trend is more of a discrepancy for the CO2 hypothesis. CO2 warms the earth by absorbing the infrared band of sunlight...but sunlight obviously doesn't exist at night. You can only explain away the discrepancy by assuming radiative capture from the earth's surface...and clouds do that much better than CO2.

> "Svensmark also had to revamp his theory after it was found that he used an incomplete cloud cover model"

This just isn't true at all. His base theory has remained unchanged since he began work. Obviously his team uses more detailed models now, but the correlation demonstrated between cosmic ray flux and cloud formation has not only improved with these, but more importantly it has been experimentally confirmed with his team's work on the SKY cloud chamber.

That's when Svensmark's research really hit the limelight. Because-- in sharp contrast to CO2-based global climate models-- he has a working theory with excellent correlative properties coupled with hard experimental data to back it up.


RE: Here's the reference...
By Rovemelt on 7/31/2007 6:45:26 PM , Rating: 2
Svensmark changed his 1997 model after it was found that he used an incomplete cloud cover model:

Here is a link to a primary ref PDF that explains it:
http://stephenschneider.stanford.edu/Publications/...
It's a big pdf, so it takes time to download. So much for the lack of controversy over Svensmark's findings.

And your analysis of warming trends and cloud cover needs adjustment:

Check out page 188+ of this book "Solar Activity and Earth's Climate" By Rasmus E. Benestad (physicist studying climate change): http://books.google.com/books?id=BdkCqOb6ivIC&pg=P...

That chapter highlights Svensmark research and shows how many holes it has, with references. It also presents the daytime/nighttime temperature problem that Svensmark research can't account for.


RE: Here's the reference...
By masher2 (blog) on 8/1/2007 10:49:14 AM , Rating: 1
> "Here is a link to a primary ref PDF that explains it:"

Laut was found to have been massaging the data rather vigorously to prove his point, as well as using some erronenous data source. Svensmark's rebuttal explains it fairly well:

quote:
[Laut] presents a figure 1c, which he claims is "a corrected and updated version for Fig 1a", where the correction consists in removing what [Laut] claims are "the irrelevant DMSP data". Laut also removes - without any comments or arguments = the Nimbus-7 data from 79-85....the careful reader [will] note he does not use the same DMSP data in his figures 1a and 1b...this is because the data in fig. 1a are restricted to Southern hemisphere over oceans, whereas fig 1b [is] restricted to midlatitude oceans.

It is remarkable that Laut references Kernthaler (1999)..as part of his argumentation against the above work...Kernthaler used the flawed ISCPP-C2 cloud type data, which makes their conclusions obsolete...
In any case, the entire argument is out of data, as Svensmark's current work is much more sophisticated, shows an even greater correlation, and is backed by hard experimental data from the SKY cloud formation experiments. You don't NEED a mathematical model to prove cosmic rays affect cloud formation when you've shown it actually occurs in the lab. It's a real, proven effect, not a hypothetical model.


RE: Here's the reference...
By High Planes Drifter on 8/1/2007 5:27:48 PM , Rating: 2
quote:
Clouds are water vapor,

Clouds are not water vapor.

quote:
CO2 warms the earth by absorbing the infrared band of sunlight...but sunlight obviously doesn't exist at night.

Wrong again.

CO2 warms the atmosphere by absorbing the IR band of radiation. Much of the sunlight received by the earth is converted to IR and is readmitted by the earth. Some of this does this does indeed happen at night. The fact that the earth emits more IR radiation than it receives is why greenhouse gasses act to trap more heat closer to the earth than simply blocking IR access to the earth in the first place and acting to cool the earth.


RE: Here's the reference...
By masher2 (blog) on 8/1/2007 5:41:56 PM , Rating: 2
> "CO2 warms the atmosphere by absorbing the IR band of radiation. Much of the sunlight received by the earth is converted to IR and is readmitted by the earth. Some of this does this does indeed happen at night"

Which, if you read my entire post, is exactly what I said. The key phrase is "radiative capture". The fact remains that clouds perform this role much better than CO2, which explains why overcast nights tend to be much warmer than clear ones.

> "Clouds are not water vapor."

More strictly, clouds are droplets condensed from water vapor. I've read research papers by atmospheric physicists arguing over what the actual definition of a cloud should be; I'm not going to stress too much over semantics here.


By High Planes Drifter on 8/1/2007 10:40:03 PM , Rating: 2
I find it vary hard to believe that you have read the paper. From Lockwood and Frohlich et al:

quote:
…Figure 3 shows the variations since 1970 of the solar cycle means of the sunspot number hRiL, the open solar flux hFSiL, the climax cosmic ray neutron counts hCiL and the solar cycle length L. In each case, the solar cycle variation has been smoothed to give the red line, using exactly the same procedure as described in §3 for figure 3a. Figure 3 shows that the smoothed sunspot number hRiL clearly peaked around 1985 and has declined since and the anticorrelation with L seen in figure 4 has persisted. The open solar flux peaked around 1987, the 2-year lag after hRiL being consistent with the time constant from models of its long-term variation (Solanki et al. 2000, 2001; Wang et al. 2005b). The anticorrelation between cosmic ray fluxes and the open solar flux, observed on both annual and decadal time scales (Rouillard & Lockwood 2004), is here shown to also apply to the trends revealed when the solar cycle is averaged out. hTSIiL has fallen since the peak hRiL in 1985 and this is reflected in the significantly lower peak seen at the current solar minimum than during the previous two solar minima (see figure 1d ).

p10

quote:
Our results show that the observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanisms is invoked and no matter how much the solar
variation is amplified.

p11


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