Dr. Jeff Masters' WunderBlog

How much will global sea level rise this century?

Posted by: Dr. Jeff Masters, 14:49 GMT le 13 juillet 2009

How much will global sea level rise this century? Well, global sea level rise began in the late 1700s, and accelerated to 1.2 inches (3 cm) per decade over the past 25 years (see my post, Sea level rise: what has happened so far). If the conditions that led to this acceleration continue, we can expect sea level will rise an additional 1.1 ft (0.34 m) by 2100 (Jevrejeva et al., 2008). At a minimum, sea level rise during the 21st century should equal that of the 20th century, about seven inches (0.6 ft, 0.18 meters). This is the lower bound given by the IPCC in its 2007 assessment, which projected sea level rise of 0.6 - 1.9 ft (0.18 - 0.59 m) by 2100. However, they cautioned in their report that due to the lack of knowledge about how melting glaciers behave, the actual sea level rise might be higher. There is a growing consensus that the 2007 IPCC sea level rise estimates are much too low.

Figure 1. Observed global sea level from tide gauges (red line, pink color is the uncertainty range) and satellite measurements (green line), with forecasts for the future. The blue colors show the range of projections for three different forecasts (the forecasts overlap, but this overlap is not shown). Image modified from U.S. EPA.

The 2007 IPCC report: too conservative?
Three major sea level rise studies published since the 2007 IPCC report have argued that the IPCC's projections of sea level rise are too conservative. A paper published in 2008 in Science by Pfeffer et al. (2008) concluded that the "most likely" range of sea level rise by 2100 is 2.6 - 6.6 ft (0.8 - 2.0 meters). Their estimates came from a detailed analysis of the processes the IPCC said were understood too poorly to model--the ice flow dynamics of glaciers in Greenland and Antarctica. For example, increased glacial flow may result when water draining from melt water lakes on the surface of the glacier to the base of the glacier, where it acts as a lubricant. The authors cautioned that "substantial uncertainties" exist in their estimates, and that the cost of building higher levees to protect against sea level rise is not trivial.

Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany looked at the observed relationship between changes in sea level and global temperatures since 1900 (Rahmstorf, 2007). Rahmstorf showed that that there has been a direct relationship between sea level rise and global average temperature: 0.1 - 0.3 meters of sea level rise occurs per °C increase in global temperature. Using this relationship, Rahmstorf predicted 1.6 - 4.6 ft (0.5 - 1.4 m) of sea level rise by 2100, since the IPCC predicts that global temperatures will rise 1.4° to 5.8°C. Rahmstorf concluded, "very low sea-level rise values as reported in the 2007 IPCC report now appear rather implausible in the light of the observational data".

A similar approach was taken by Grinsted et al. (2009), but they extended the relationship between sea level and global average temperature all the way back to 200 A.D. using proxy records. They concluded that ice sheets respond more quickly to temperature changes than the computer models used in the 2007 IPCC assessment. The authors estimated that "IPCC projections of sea level rise 2090 - 2099 are underestimated by roughly a factor of three". The authors predicted that global sea level will be rising 11 mm/year by 2050--four times faster than the 20th century rise. By the last decade of this century, they forecasted that sea level will rise 3.0 - 4.3 feet (0.9 - 1.3 meters), using the IPCC's A1B "business as usual" scenario.

The long-range forecast: using paleohistory to forecast sea level rise
We can also look at times in Earth's past that had similar climate to what we expect by the year 2100. The best time to look at is probably just before the most recent ice age--the Eemian. This interglacial period 130,000 - 114,000 years ago featured temperatures near the poles that were 2°C warmer than present-day temperatures. Tree line lay about 500 miles farther north in the Canadian Arctic, and the hippopotamus ranged as far north as the Thames River in England. A similar climate is expected under some of the more moderate global warming scenarios envisioned by the IPCC. Sea level is believed to have been 4 - 6 meters (13 - 20 feet) higher than at present during the Eemian, but there is at least one unpublished study that presents evidence that global sea level was 6 - 9 meters (20 - 30 feet) higher. If the climate does warm to levels seen in the Eemian, it is widely believed that we would again see sea levels at least 4 - 6 meters higher than the present-day levels. Clearly, sea level rises of this magnitude would be ruinous to society. However, most climate change scientists believe that it would take many centuries for enough ice to melt from the Greenland and West Antarctic ice sheets to create sea level rises of 4 - 6 meters.

However, the scientist who is arguably the most visible and authoritative climate scientist in the world, Dr. James Hansen of NASA, stated (Hansen, 2007) "I find it almost inconceivable that business-as-usual climate change would not yield a sea level change of the order of meters on the century timescale" (IPCC business-as-usual (BAU) scenarios assume that emissions of CO2 and other greenhouse gases will continue to increase year after year). Hansen gave a hypothetical but potentially realistic scenario where the sea level rise due to ice sheet disintegration doubles every decade, leading to a 16 foot (5 meter) sea level increase by 2100. He noted that during the Plio-Pleistocene period 2 - 3 million years ago, CO2 levels were similar to today (350 - 450 ppm), and global temperatures were 2 - 3°C warmer, similar to what we expect by the end of the century. Yet, this Plio-Pleistocene world was "a dramatically different planet, without Arctic sea ice in the warm seasons and with a sea level 25 ± 10 m higher."

Summary
To summarize, here are some predictions of how high global sea level might rise by 2100:

0.6 ft (0.18 m): Constant linear rise, equal to 20th century rise
1.1 ft (0.34 m): Constant acceleration model (Jevrejeva et al., 2008)
0.6 - 1.9 ft (0.18 - 0.59 m): Primitive models of ice sheets (IPCC, 2007)
1.6 - 4.6 ft (0.5 - 1.4 m): Relationship between temperature and sea level rise since 1900 (Rahmstorf, 2007)
3.0 - 4.3 feet (0.9 - 1.3 m): Relationship between temperature and sea level rise since 200 A.D. (Grinsted et al., 2009)
2.6 - 6.6 ft (0.8 - 2.0 meters): Considering glacier ice flow dynamics not included by the IPCC (Pfeffer et al., 2008)

In a 2009 interview with New Scientist magazine, sea level expert Stephan Rahmstorf said, "I sense that now a majority of sea level experts would agree with me that the IPCC projections are much too low." This sentiment was echoed by glaciologist Robert Bindschadler of the NASA Goddard Space Flight Center in Greenbelt, Maryland, who commented, "most of my community is comfortable expecting at least a metre by the end of this century."

In forthcoming posts in this series, I'll explore how a meter (3.28 feet) of sea level rise will affect the U.S. coast, the Caribbean, and other vulnerable locations world-wide. It would be wise to begin preparing now for a potential rise in sea level of a meter this century. In particular, development near the coasts should be severely restricted in low-elevation zones. It will be very expensive to protect or move infrastructure away from rising seas later this century. However, even if the rate of sea level rise doubles every decade, those of us who are over the age of 50 will not live to see sea level rise cause a significant disruption to society. There is time for society to prepare for the rising sea.

References
Jevrejeva, S., J.C. Moore, A. Grinsted,, and P.L. Woodworth, 2008, "Recent global sea level acceleration started over 200 years ago?", Geophysical Research Letters, 35, L08715, doi:10.1029/2008GL033611, 2008.

Grinsted, A., J.C. Moore, and S. Jevrejeva, 2009, "Reconstructing sea level from paleo and projected temperatures 200 to 2100 AD", Climate Dynamics, DOI 10.1007/s00382-008-0507-2, 06 January 2009.

Hansen, J., 2007, "Scientific reticence and sea level rise",, Environ. Res. Lett. 2 (April-June 2007) 024002 doi:10.1088/1748-9326/2/2/024002.

IPCC (Intergovernmental Panel on Climate Change), 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, UK, and New York, 996 pp.

Pfeffer, W.T., J.T. Harper, and S. O'Neel, 2008, "Kinematic Constraints on Glacier Contributions to 21st-Century Sea-Level Rise", Science 321 no. 5894, pp. 1340-1343, 5 September 2008. DOI: 10.1126/science.1159099

Rahmstorf, Stefan. "Sea-Level Rise: A Semi-Empirical Approach to Projecting Future." Science 315 (2007): 368–370.

Other posts in this series
Sea level rise: what has happened so far
U.S. vulnerability to sea level rise

Wednesday, I'll take a look at the Atlantic hurricane forecast for the remainder of July. There's currently nothing out there worth discussing--will it stay that way?

Dr. Ricky Rood has some interesting commentary on the new climate change legislation that passed the House last month, and will go to the Senate in September.

Jeff Masters

Categories: Climate Change Sea level rise

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2402. KEEPEROFTHEGATE (Mod) 11:45 GMT le 15 juillet 2009
Quoting IKE: TROPICAL WEATHER OUTLOOK NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 800 AM EDT WED JUL 15 2009 FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO... TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS. $$ FORECASTER ROBERTS/BRENNAN Not sure the EATL waves are going to amount to much. The first one that was near 35W yesterday, looks a lot weaker. The one to it's east has diminished some over night. Another one is now emerging off of Africa. They all seem to diminish as they move west. doing exactly as there surpose to most do fad after movin over open water Meteosat 4 km IR4 Floater (CIRA Personnel Only) far east atlantic Member Since: 15 juillet 2006 Posts: 143 Comments: 40365

2403. SpicyAngel1072 11:45 GMT le 15 juillet 2009
Quoting IKE: WOW! is that normal for the african dust to stretch that far our way? Member Since: 1 septembre 2008 Posts: 0 Comments: 315

2405. IKE 11:47 GMT le 15 juillet 2009
Quoting SpicyAngel1072: WOW! is that normal for the african dust to stretch that far our way? That's rather high for that area...but they do get dust. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2406. IKE 11:49 GMT le 15 juillet 2009
Quoting KEEPEROFTHEGATE: doing exactly as there surpose to most do fad after movin over open water Meteosat 4 km IR4 Floater (CIRA Personnel Only) far east atlantic Agree it's normal...just the way some were jumping on the invest and yellow circle bandwagon the last 2 days... Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2407. IKE 11:50 GMT le 15 juillet 2009
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 421 AM AST WED JUL 15 2009 .SYNOPSIS...A STRONG SAHARAN AIR LAYER WITH HAZE/DUST AND GUSTY WINDS TO AFFECT THE REGION TODAY AND LAST INTO FRIDAY. NEXT TROPICAL WAVE WILL CROSS THE AREA ON SATURDAY WITH AN INCREASE IN SHRA/TSRA ACTIVITY. A MORE MOIST TROPICAL AIR MASS IS EXPECTED TO AFFECT THE REGION EARLY NEXT WEEK INCREASING PRECIPITATION CHANCES. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2408. WxLogic 11:51 GMT le 15 juillet 2009
Will be interesting to see what will happen with the wave that just came out of Africa and our AOI. Definitely it was unable to maintain itself during the night time hours. The wave out of Africa appears to be moving a more quicker so these 2 could merge. Let's see what happens in 24HR with these 2. :) Member Since: 14 août 2008 Posts: 4 Comments: 4666

2409. IKE 11:53 GMT le 15 juillet 2009
Looks like as the trough amplifies in the eastern USA, a strong, getting stronger, high will build in in the Atlantic and race these EATL waves W to WNW. Islands may get needed rain.... Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2410. KEEPEROFTHEGATE (Mod) 11:57 GMT le 15 juillet 2009
it would have to be a lot more organized to get a yellow or any other colour circle for that matter that far out in east atl. Member Since: 15 juillet 2006 Posts: 143 Comments: 40365

2411. IKE 11:59 GMT le 15 juillet 2009
6Z NOGAPS takes the vorticity of the EATL waves into the Caribbean.... Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2412. TheWeatherMan504 12:01 GMT le 15 juillet 2009
Quoting KEEPEROFTHEGATE: it would have to be a lot more organized to get a yellow or any other colour circle for that matter that far out in east atl. The Broad Area of Low Pressure over the Central Atlantic needs a jump start. The Jump Start just crossed the African Coastline this Morning it should reach the Broad Area of Low Pressure in 24 Hours... Member Since: 18 mai 2008 Posts: 2 Comments: 1037

2413. WxLogic 12:02 GMT le 15 juillet 2009
Quoting IKE: Looks like as the trough amplifies in the eastern USA, a strong, getting stronger, high will build in in the Atlantic and race these EATL waves W to WNW. Islands may get needed rain.... They sure do... I do remember the Haze/Dust caused by the SAL when I used to live in PR. Pretty horrible... it was so thick at times that you could see the shadows of planes contrails striking through the sky and good luck with any TSTM activity... anything that tried to form almost failed to develop 80% to 90% of the time. RGB satellite do nicely show the leading edge of the SAL now approaching E DR. Member Since: 14 août 2008 Posts: 4 Comments: 4666

2414. KEEPEROFTHEGATE (Mod) 12:08 GMT le 15 juillet 2009
i owe i owe so its off to work i go i will check back in at my break around 1030 edt and again at lunch at 12 see ya later tropical weather freaks Member Since: 15 juillet 2006 Posts: 143 Comments: 40365

2415. IKE 12:12 GMT le 15 juillet 2009
Quoting WxLogic: They sure do... I do remember the Haze/Dust caused by the SAL when I used to live in PR. Pretty horrible... it was so thick at times that you could see the shadows of planes contrails striking through the sky and good luck with any TSTM activity... anything that tried to form almost failed to develop 80% to 90% of the time. RGB satellite do nicely show the leading edge of the SAL now approaching E DR. I see it on satellite... 00Z GFS gets the CATL high up to around 1032 mb's...that is a strong high. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2416. wunderkidcayman 12:13 GMT le 15 juillet 2009
good morning everyone quickscat shows a surface spin at 10n 37w-38w Link Member Since: 13 juin 2009 Posts: 2 Comments: 5381

2417. wunderkidcayman 12:18 GMT le 15 juillet 2009
ncep/emc cyclone track 2009071500 atlantic ocean basin model storm tracks Link Member Since: 13 juin 2009 Posts: 2 Comments: 5381

2418. stormpetrol 12:19 GMT le 15 juillet 2009
Member Since: 29 avril 2007 Posts: 0 Comments: 6394

2420. Ossqss 12:20 GMT le 15 juillet 2009
The quake did not produce much of a Tsunami from the statement fortunately. A tsunami has been observed at the following sites: Location Lat. Lon. Time Amplitude ------------------------ ----- ------ ------- ----------- JACKSON BAY, NZ 43.97S 168.62E 10:18 UTC 0.17M /0.5FT Member Since: 12 juin 2005 Posts: 6 Comments: 8154

2421. WxLogic 12:26 GMT le 15 juillet 2009
Quoting KEEPEROFTHEGATE: i owe i owe so its off to work i go i will check back in at my break around 1030 edt and again at lunch at 12 see ya later tropical weather freaks lol... l8r KOTG Member Since: 14 août 2008 Posts: 4 Comments: 4666

2422. TheCaneWhisperer 12:31 GMT le 15 juillet 2009
Quoting IKE: That's rather high for that area...but they do get dust. Occasionally they make it to the states too. It looks like this SAL outbreak may just do that.

2424. DVG 12:43 GMT le 15 juillet 2009
Had enough dust on my white grand am to wipe my finger and collect a sizeable amount off of it. In Jax Fla wsa about 94 I think. Member Since: 29 août 2007 Posts: 0 Comments: 244

2425. weathermanwannabe 12:45 GMT le 15 juillet 2009
Good Morning....All's quiet for now closer to home and the models, as noted by 456, are "looking" at the future in terms of possible development of the wave closer to the Islands and Gulf "low". The wave is more tangible and the "low" is an educated guess right now. As normal for this time of the year, going towards August, sheer has really dropped around the Islands and SE US and starting to drop in the Central Atlantic. Wife and the kids are going out of town this weekend [ :) ] so I'll be able to keep a close eye on the Gulf situation from the house in Tallahassee over the weekend with "unlimited" access to the family computer...Lol.....That one will all depend on whether an tangible remnant, if the front is developed enough, can linger in the Gulf for a bit.....I'm just looking at a rain/flooding event for the Northern Florida area right now if the front stalls in our region. Member Since: 8 août 2006 Posts: 0 Comments: 6675

2426. Tazmanian 12:47 GMT le 15 juillet 2009
000 WHXX01 KMIA 151243 CHGE77 TROPICAL CYCLONE GUIDANCE MESSAGE NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1243 UTC WED JUL 15 2009 DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS. PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE AND SUBTROPICAL CYCLONE INFORMATION. EAST PACIFIC OBJECTIVE AIDS FOR TROPICAL CYCLONE DOLORES (EP052009) 20090715 1200 UTC ...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS... 090715 1200 090716 0000 090716 1200 090717 0000 LAT LON LAT LON LAT LON LAT LON BAMS 14.6N 115.1W 16.0N 117.4W 17.2N 120.1W 18.3N 122.9W BAMD 14.6N 115.1W 15.8N 117.2W 17.0N 119.5W 18.2N 121.9W BAMM 14.6N 115.1W 15.9N 117.3W 17.1N 119.6W 18.4N 122.2W LBAR 14.6N 115.1W 15.6N 117.2W 16.9N 120.1W 18.2N 123.5W SHIP 35KTS 40KTS 42KTS 43KTS DSHP 35KTS 40KTS 42KTS 43KTS ...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS... 090717 1200 090718 1200 090719 1200 090720 1200 LAT LON LAT LON LAT LON LAT LON BAMS 19.4N 125.8W 21.8N 131.3W 24.8N 136.3W 27.8N 139.9W BAMD 19.4N 124.5W 22.3N 129.4W 26.4N 132.5W 32.2N 133.4W BAMM 19.8N 125.0W 22.8N 130.4W 26.5N 134.4W 30.9N 135.9W LBAR 19.6N 127.0W 22.6N 132.7W 27.6N 134.6W 34.8N 133.5W SHIP 37KTS 24KTS 0KTS 0KTS DSHP 37KTS 24KTS 0KTS 0KTS ...INITIAL CONDITIONS... LATCUR = 14.6N LONCUR = 115.1W DIRCUR = 305DEG SPDCUR = 9KT LATM12 = 13.5N LONM12 = 113.5W DIRM12 = 304DEG SPDM12 = 8KT LATM24 = 12.6N LONM24 = 112.0W WNDCUR = 35KT RMAXWD = 90NM WNDM12 = 30KT CENPRS = 1006MB OUTPRS = 1010MB OUTRAD = 200NM SDEPTH = M RD34NE = 100NM RD34SE = 150NM RD34SW = 0NM RD34NW = 50NM Member Since: 21 mai 2006 Posts: 5088 Comments: 111307

2427. IKE 12:50 GMT le 15 juillet 2009
EAST-PAC now up to the "D" storm. Atlantic still looking for the A. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2428. Cotillion 12:55 GMT le 15 juillet 2009
Umbridge is here! And on the same day Harry Potter comes out to the pictures. That's some coincidence. :P Member Since: 23 août 2008 Posts: 7 Comments: 5300

2429. Tazmanian 12:55 GMT le 15 juillet 2009
and its olny july lol Member Since: 21 mai 2006 Posts: 5088 Comments: 111307

2430. TheWeatherMan504 12:56 GMT le 15 juillet 2009
Quoting Cotillion: Umbridge is here! And on the same day Harry Potter comes out to the pictures. That's some coincidence. :P LOL... Member Since: 18 mai 2008 Posts: 2 Comments: 1037

2431. wunderkidcayman 12:58 GMT le 15 juillet 2009
I will see you guys later Member Since: 13 juin 2009 Posts: 2 Comments: 5381

2432. Orcasystems 12:59 GMT le 15 juillet 2009
Blog Update Reflector site for those at work, which includes Weather456, daily updates AOI AOI Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2433. weathermanwannabe 13:03 GMT le 15 juillet 2009
Quoting TheWeatherMan504: LOL... Yup; had to drop off my 16 year old at the movies last night for the opening at Midnight and pick her up at 2:30....A little sleepy this morning......... Member Since: 8 août 2006 Posts: 0 Comments: 6675

2434. bdkennedy1 13:03 GMT le 15 juillet 2009
Wow! Thanks! Would never have known that unless you posted it. Quoting IKE: EAST-PAC now up to the "D" storm. Atlantic still looking for the A. Member Since: 21 juillet 2005 Posts: 0 Comments: 28

2435. Tazmanian 13:04 GMT le 15 juillet 2009
i can thanks EL Nino for this Member Since: 21 mai 2006 Posts: 5088 Comments: 111307

2436. Orcasystems 13:04 GMT le 15 juillet 2009
Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2437. DeVryguy 13:05 GMT le 15 juillet 2009
Let the reader note that Dr. Masters latest blog concerning sea level rise--with it's dramatic graph of a human figure standing next to an awesome and precipitous change in sea level in the closing decades of the 21st century--cites as a reference an article by Rahmstorf. Click on the link provided one notes that the article is entitled "A Semi-Empirical Approach to Projecting Future Sea-Level Rise." The use of the term "semi-empirical" in much scientific work is quite often little more than a synonym for guess work and reminds the educated reader that the 18th century use of the word empirical was entirely pejorative--as in pulling something from a place where the sun doesn't shine. But more than that, if you click on the second technical comment you will read that Rahmstorf's method doesn't produce a "robust" regression coefficient. The commentators propose a different method similar to what is commonly used in econometrics. The irony here is that, judging by the spectacular failure of the big economic brains to predict the economic collapse that occurred several months ago, one should place any confidence in an econometric method. Perhaps one should but it becomes clear as one "follows the links" on global warming in general, there's a lot of interpretation going on that stretches the limit of the data. I also remind the reader that whatever the quality of today's sea level data, such quality must fall off sharply when one goes back in time even a few decades. According to Dr. Masters, "The authors cautioned that "substantial uncertainties" exist in their estimates, and that the cost of building higher levees to protect against sea level rise is not trivial." "Statistically substantial uncertainties" are often accompanied by substantial uncertainties in the error bars themselves which means that all of the ranges given may be totally off. The author's work may be consistent with zero change in sea-level in the next 100 years or even negative changes. Indeed, the ranges given by Jevrejeva (0.6 - 1.9 ft) are outside the ranges of Pfeffer (2.6 ft - 6.6ft). Perhaps if Jevrejeva had been a teensy bit more optimistic he might have included 0ft within his range? Not by fudging but compared the quality of physical data one encounters in other branches of the physical sciences (like estimates of the velocity of light, for example), perhaps the author should place less confidence in his model and simply say that we really don't know enough to definitively exclude it? When Dr. Masters says, in reference to Pheffer's results, "Their estimates came from a detailed analysis of the processes the IPCC said were understood too poorly to model" he indavertantly illustrates another problem with climate research: the mixing of modeling and data. Dynamical modeling is fraught with difficult mathematical problems even with today's powerful computers. Much of the modeling involves fluid dynamics and if one looks at other areas where this is used--which aren't freighted with the politics of climate change--one will get a sobering view of just how hard it is. The free admixture of results--now from models, now from "data"--that is so common in the literature of climate change should raise red flags. Such admixture is also common in economics and I'll leave it to the reader to decide whether, given the powerful models and impressive mathematical apparatus they use, they've come close to predicting, say, the business cycle--the ability to do so being something of obvious concern and benefit to all. Member Since: 19 septembre 2003 Posts: 0 Comments: 1

2438. IKE 13:12 GMT le 15 juillet 2009
Quoting bdkennedy1: Wow! Thanks! Would never have known that unless you posted it. You're welcome..... Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2439. willdunc79 13:12 GMT le 15 juillet 2009
Just checking in so how are the 3 tropical waves doing this morning? Gave they poofed yet? Member Since: 27 juin 2009 Posts: 0 Comments: 152

2440. Chicklit 13:12 GMT le 15 juillet 2009
From Crown Weather: . . . am closely monitoring the eastern Atlantic, which is dotted by three separate tropical disturbances. One near 40 West Longitude, the second near 27 West Longitude and a third near 18 West Longitude. It appears, based on satellite imagery, that the two disturbances behind the first are moving quicker and I would suspect in the next couple of days that all three of these disturbances will try to congeal into one identifiable tropical disturbance and this seems to be what the GFS model has been trying to say all along. What?! Member Since: 11 juillet 2006 Posts: 14 Comments: 10234

2441. IKE 13:16 GMT le 15 juillet 2009
Quoting Chicklit: From Crown Weather: . . . am closely monitoring the eastern Atlantic, which is dotted by three separate tropical disturbances. One near 40 West Longitude, the second near 27 West Longitude and a third near 18 West Longitude. It appears, based on satellite imagery, that the two disturbances behind the first are moving quicker and I would suspect in the next couple of days that all three of these disturbances will try to congeal into one identifiable tropical disturbance and this seems to be what the GFS model has been trying to say all along. What?! Triplets will become one and move to the west...to WNW. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2442. TheWeatherMan504 13:21 GMT le 15 juillet 2009
Quoting DeVryguy: Let the reader note that Dr. Masters latest blog concerning sea level rise--with it's dramatic graph of a human figure standing next to an awesome and precipitous change in sea level in the closing decades of the 21st century--cites as a reference an article by Rahmstorf. Click on the link provided one notes that the article is entitled "A Semi-Empirical Approach to Projecting Future Sea-Level Rise." The use of the term "semi-empirical" in much scientific work is quite often little more than a synonym for guess work and reminds the educated reader that the 18th century use of the word empirical was entirely pejorative--as in pulling something from a place where the sun doesn't shine. But more than that, if you click on the second technical comment you will read that Rahmstorf's method doesn't produce a "robust" regression coefficient. The commentators propose a different method similar to what is commonly used in econometrics. The irony here is that, judging by the spectacular failure of the big economic brains to predict the economic collapse that occurred several months ago, one should place any confidence in an econometric method. Perhaps one should but it becomes clear as one "follows the links" on global warming in general, there's a lot of interpretation going on that stretches the limit of the data. I also remind the reader that whatever the quality of today's sea level data, such quality must fall off sharply when one goes back in time even a few decades. According to Dr. Masters, "The authors cautioned that "substantial uncertainties" exist in their estimates, and that the cost of building higher levees to protect against sea level rise is not trivial." "Statistically substantial uncertainties" are often accompanied by substantial uncertainties in the error bars themselves which means that all of the ranges given may be totally off. The author's work may be consistent with zero change in sea-level in the next 100 years or even negative changes. Indeed, the ranges given by Jevrejeva (0.6 - 1.9 ft) are outside the ranges of Pfeffer (2.6 ft - 6.6ft). Perhaps if Jevrejeva had been a teensy bit more optimistic he might have included 0ft within his range? Not by fudging but compared the quality of physical data one encounters in other branches of the physical sciences (like estimates of the velocity of light, for example), perhaps the author should place less confidence in his model and simply say that we really don't know enough to definitively exclude it? When Dr. Masters says, in reference to Pheffer's results, "Their estimates came from a detailed analysis of the processes the IPCC said were understood too poorly to model" he indavertantly illustrates another problem with climate research: the mixing of modeling and data. Dynamical modeling is fraught with difficult mathematical problems even with today's powerful computers. Much of the modeling involves fluid dynamics and if one looks at other areas where this is used--which aren't freighted with the politics of climate change--one will get a sobering view of just how hard it is. The free admixture of results--now from models, now from "data"--that is so common in the literature of climate change should raise red flags. Such admixture is also common in economics and I'll leave it to the reader to decide whether, given the powerful models and impressive mathematical apparatus they use, they've come close to predicting, say, the business cycle--the ability to do so being something of obvious concern and benefit to all. That has to be the smartest post on the subject that I have seen on this Blog in the 3 Years I have been here. Member Since: 18 mai 2008 Posts: 2 Comments: 1037

2443. Chicklit 13:23 GMT le 15 juillet 2009
Quoting IKE: Triplets will become one and move to the west...to WNW. I am finding that hard to believe. More believable that everything will fall apart and one tiny little LLC will survive from it all. And as we all know, it only takes one spin in the right conditions to create havoc. So let's hope it's just a rainmaker. Darn. This is nasty business. The Islands need the rain, that's all. Batten down the hatches, Mates! Member Since: 11 juillet 2006 Posts: 14 Comments: 10234

2444. Orcasystems 13:23 GMT le 15 juillet 2009
Posted by: JeffMasters, 2:49 PM GMT on July 13, 2009 "Wednesday, I'll take a look at the Atlantic hurricane forecast for the remainder of July. There's currently nothing out there worth discussing--will it stay that way?" Looking forward to seeing what Jeff has to say today. Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2445. IKE 13:29 GMT le 15 juillet 2009
Quoting Orcasystems: Posted by: JeffMasters, 2:49 PM GMT on July 13, 2009 "Wednesday, I'll take a look at the Atlantic hurricane forecast for the remainder of July. There's currently nothing out there worth discussing--will it stay that way?" Looking forward to seeing what Jeff has to say today. Let me guess...I see very little for the next 7 days. I give it a 20% chance of a system by the end of July. Member Since: 9 juin 2005 Posts: 23 Comments: 37044

2446. Orcasystems 13:34 GMT le 15 juillet 2009
Quoting IKE: Let me guess...I see very little for the next 7 days. I give it a 20% chance of a system by the end of July. I'm going to go with 50%, and 100% in August. Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2447. ALCoastGambler 13:35 GMT le 15 juillet 2009
Quoting Orcasystems: I'm going to go with 50%, and 100% in August. come on now Orca don't be such a downcaster for August.....lol

2448. ALCoastGambler 13:37 GMT le 15 juillet 2009
Morning Ike, Orca. How are ya'll this beautiful Alabama morning?

2449. Orcasystems 13:37 GMT le 15 juillet 2009
Quoting ALCoastGambler: come on now Orca don't be such a downcaster for August.....lol ROFL.. just betting with the averages.. mind you..if I had done that with the first half.. I would be broke by now. Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2450. Orcasystems 13:39 GMT le 15 juillet 2009
Quoting ALCoastGambler: Morning Ike, Orca. How are ya'll this beautiful Alabama morning? So far so good.. watching the Pacific.. watching NZ for after shocks.. reading Drudge and drinking coffee. Then.. off to work :( Member Since: 1 octobre 2007 Posts: 77 Comments: 26077

2451. ALCoastGambler 13:43 GMT le 15 juillet 2009
Quoting Orcasystems: So far so good.. watching the Pacific.. watching NZ for after shocks.. reading Drudge and drinking coffee. Then.. off to work :( WORK ohh no can't use that word around me I'll melt. I'm just gonna sit here and play poker, drink coffee, and read, the posts all day. I hope

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