[Al_U_Card]

Too much to cover easily. Harvey is staying put and may even back out over the Gulf to increase the precipitation. This may make Katrina look like a minor issue.

[Al_U_Card]

Live coverage

[PassedOut]

I hope that scientists are looking for the causes of extreme weather events. Maybe something should be done.

[barmar]

 PassedOut, on 2017-August-28, 14:59, said:

I hope that scientists are looking for the causes of extreme weather events. Maybe something should be done.

While it seems likely that extreme hurricanes are related to climate change, I heard a client scientist on NPR talking about the fact that we don't have enough historical data about hurricanes to draw good conclusions about correlation. Unlike detailed temperature information, which has been gathered for over a century, we've only been able to get accurate information about hurricanes since the advent of weather satellites. Before then, we could only get details about hurricanes once they made landfall, not the entire lifetime of the storm -- we could only get information about hurricanes over the oceans if a ship happened to be unlucky enough to sail into it, and then lucky enough to get out with survivors.

He thought that within a decade or so we'll have enough history to make accurate correlations.

[Al_U_Card]

 barmar, on 2017-August-28, 15:10, said:

While it seems likely that extreme hurricanes are related to climate change, I heard a client scientist on NPR talking about the fact that we don't have enough historical data about hurricanes to draw good conclusions about correlation. Unlike detailed temperature information, which has been gathered for over a century, we've only been able to get accurate information about hurricanes since the advent of weather satellites. Before then, we could only get details about hurricanes once they made landfall, not the entire lifetime of the storm -- we could only get information about hurricanes over the oceans if a ship happened to be unlucky enough to sail into it, and then lucky enough to get out with survivors.

He thought that within a decade or so we'll have enough history to make accurate correlations.

And with land-falling hurricanes being a representative sample of all hurricanes, a simple recount of major (Cat4 and 5) storms in the US would show how a changing climate might relate to intensity and frequency. (CO2 as a cause of said change not being relevant as only the change is under analysis.) .

Dr. P. Klotzbach provides (courtesy of Judith Curry's blog)

[Zelandakh]

What Philip Klotzbach writes aboutcat 4-5 hurricanes is that the data prior to 1990 is unreliable and that the data from 1990 is "in line with expectations from climate models". Katrina illustrates the issue with the posted list, one that I am surprised JC did not address. Katrina had wind speeds of 55 m/s at landfall, one short of the requirement for cat 4. Who here believes that the hurricane of 1886 had its wind speeds measured to the same accuracy?

I think there is a fair chance that Katrina would have made the list in certain decades and that some of the historical hurricanes would be downgraded to cat 3s if they occurred today. It is hard to tell - one reason that Klotzbach warns against putting too much weight on pre-satellite data.

What almost all scientists working in this area expect as the climate warms is for the number of hurricanes to decrease but the number of extreme events to increase. But it is a gradual affair, with changes over a 20 year period being negligible against the noise of natural variability.

[Al_U_Card]

 PassedOut, on 2017-August-28, 14:59, said:

I hope that scientists are looking for the causes of extreme weather events. Maybe something should be done.

We have already contributed billions in tax dollars, to what end? Change our orbit? Alter the ocean currents? Affect solar cycles? We can't even introduce a new species to control a pest without causing a disaster. I suppose giving away your inheritance would please your grandkids... or perhaps just providing them with the creature comforts that we take for granted like cheap and abundant electricity...unless we switch to wind-power, then it will be intermittent and expensive.

[Al_U_Card]

 Zelandakh, on 2017-August-28, 18:12, said:

What Philip Klotzbach writes aboutcat 4-5 hurricanes is that the data prior to 1990 is unreliable and that the data from 1990 is "in line with expectations from climate models". Katrina illustrates the issue with the posted list, one that I am surprised JC did not address. Katrina had wind speeds of 55 m/s at landfall, one short of the requirement for cat 4. Who here believes that the hurricane of 1886 had its wind speeds measured to the same accuracy?

I think there is a fair chance that Katrina would have made the list in certain decades and that some of the historical hurricanes would be downgraded to cat 3s if they occurred today. It is hard to tell - one reason that Klotzbach warns against putting too much weight on pre-satellite data.

What almost all scientists working in this area expect as the climate warms is for the number of hurricanes to decrease but the number of extreme events to increase. But it is a gradual affair, with changes over a 20 year period being negligible against the noise of natural variability.

Really? Interesting "argument". Kerry Emmanuel and the rest of the doomsters predicted a "new" category for CAGW hurricanes. Guess we'll have to wait for that one. Meanwhile, what is the relation between this and [CO2]? (What we can "control" relative to our emissions, as minor as they are compared to the global cycles.)

[Zelandakh]

 Al_U_Card, on 2017-August-28, 18:37, said:

Meanwhile, what is the relation between this and [CO2]?

Well this is something of a specialist area but as I understand it: CO2 is a greenhouse gas that contributes to warming the planet, resulting in warmer oceans. Warmer oceans mean that a forming tropical cyclone (TC) has a higher potential energy, giving it a higher probability of being in an extreme category. An extreme TC leaves behind more disturbance in the atmosphere than a smaller one making it more difficult for the next to form, resulting in fewer TCs overall. In addition, a warmer planet means a higher sea level, which in turn increases the damage from storm surge effects. There may be some additional minor effects, such as weak winds causing the storm to "sit" rather than turning around and heading back out to sea, but those are more difficult to prove and more controversial than the well-known and widely-accepted basic science.

If you genuinely want to know more about the physics behind the mechanisms involved then read the literature. You and I (and everyone that reads the WC) knows full well that that is not the case though so it is a waste of my time to go further. Moreover, if you want to turn this into a second thread about AGW I will suggest to th mods that we merge them - the posters that want to tune out your half-truths and lies should know where to find them.

So let us get back to the topic of hurricane Harvey. (At least) 8 people have died. It is unseemly to use their lives as childish arguments in an online forum, so please try to be serious (and at least vaguely honest) in this thread.

[Al_U_Card]

Less hand-waving is better. Most of those truisms are straight from models so not so much backed up by observation... as Judith Curry says: "anyone trying to blame Harvey on global warming doesn't have a leg to stand on."
Harvey and its aftermath will add to the numbers but fewer and weaker storms (over the last few decades) implies less impact, not more.

Not as scary as the reality of building in a swamp (flood zone) despite this and others like TS Alison in 1979 that dropped 40 in. of rain in 24 hours with much the same result. The memorial day flood of last year set the record which Harvey will likely break. A problem of their own making, of epic proportions.

[barmar]

 Al_U_Card, on 2017-August-29, 06:12, said:

Less hand-waving is better. Most of those truisms are straight from models so not so much backed up by observation... as Judith Curry says: "anyone trying to blame Harvey on global warming doesn't have a leg to stand on."
Harvey and its aftermath will add to the numbers but fewer and weaker storms (over the last few decades) implies less impact, not more.

Not as scary as the reality of building in a swamp (flood zone) despite this and others like TS Alison in 1979 that dropped 40 in. of rain in 24 hours with much the same result. The memorial day flood of last year set the record which Harvey will likely break. A problem of their own making, of epic proportions.

You can't blame a specific weather event solely on GW. What you can say about GW is that it causes the frequency and/or severity of such events to increase.

[Al_U_Card]

 barmar, on 2017-August-29, 11:35, said:

You can't blame a specific weather event solely on GW. What you can say about GW is that it causes the frequency and/or severity of such events to increase.

The models indicate that because that is how they are parameterized. Granted a "best guess" by the cogniscenti, even with more "energy" in the system, it is the differences that create the storms and with the polar regions warming faster than the temperate ones, this tends to diminish storms and their severity, based on observations over the last 3 centuries since the Little Ice Age. The other reasons you can't is that the various contributors to climate (orbital obliquity, oceanic currents and solar activity etc.) have their various aspects that create the chaotic system that is our weather. Linear approximations, like the models, just don't cut it. Those same models are twinned with economic approximations to create the impression that disaster is just around the corner. RCP 8.5 is the classic over-the-top simulation used for this. It is anything but realistic. Remember that those models "projected" a permanent drought for Texas, just a decade or so ago...

Harvey is a natural phenomenon that is, indeed, less traumatic than many other such events in cooler climes in earlier times.

[Al_U_Card]

In Houston:

2017 Harvey 52" (so far)
1978 Amelia 48"
1950 Easy . 45"
1979 Claudette 45"
2001 Allison 41"
1998 Georges 38"

Maybe they could remake the city into a sort of Venice?

[barmar]

Please take discussion about global warming back to the climate change thread. Let's keep this one just for discussion specifically about Harvey.

[Al_U_Card]

 barmar, on 2017-August-30, 09:06, said:

Please take discussion about global warming back to the climate change thread. Let's keep this one just for discussion specifically about Harvey.

Only ever about it until it went that way. Harvey is Houston's latest flooding and if the city keeps growing, it will only get worse. That they have had so little trouble proves that adaptation may well be better than mitigation. The live feed under the OP has been all about that too.

[barmar]

Houston is at a very low elevation above sea level, and it's very flat, so any time there's heavy rain they get flooding. They have a levee system that can handle most rainstorms. But Harvey dumped as much water on them as they usually get in a whole year.

[Al_U_Card]

And they have had numerous record-setting floods. What surprises me is the lack of trouble and lawlessness so far. Hopefully it will continue.

[jjbrr]

As I said in another thread, my mom is doing fine. She happened to be in a part of Conroe off of 105 that stayed safe. She's kept power the whole time and has plenty of food. I can't blame her for wanting to get away from the apartment, but some friends a few blocks south of her are completely flooded, so we'll count our blessings.

She posted some videos a few exits down on 45 where the whole interstate is underwater, along with the businesses in the strip malls along the service roads. I feel bad for the families that lost everything and have no jobs to return to.

[jjbrr]

Alucard, you're a clown.

[Zelandakh]

 jjbrr, on 2017-August-30, 21:10, said:

Alucard, you're a clown.

It's the John Lennon glassess....