How much will global sea level rise this century?
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
Reader Comments
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We were there october 2007, and if I remember correctly they were complaining about the lack of rain then as well. Coming from FL we can completely relate. Except we don't have to worry about trucking in water when it's too dry! We can still turn on our faucets (for now anyway). Seems like it can never be the right balance.. Too much or too little is more the norm!
Earthquakes the last 7 days
Could have been PressLord, he has been missing lately :)
And this morning, the NHC GFS "grid-scale feedback"?
No way no how can a model with 0.5 degree resolution (~55 km, ~34 miles) up to 180 hours and 1.0 degree resolution beyond that time (~111 km, ~68 miles) be honestly expected to start with a wave and effectively conduct some physical equations that spin up a TC.
I am surprised that GFS can even "see" Carlos. I am also surprised that GFS EVER succeeds at genesis.
All we can really do is watch it for development. The models? Seriously lacking (in either direction, pick one). Good thing we have satellites.
OH I was thinking it would be the same as my sister in St. Thomas. When her cesturn (sp?) runs dry they have to pay someone to come fill it!
Meteosat 4 km IR4 Floater
(CIRA Personnel Only)
Years ago, we had an active seismic monitoring at Charleston Southern. Not sure why that fell by the wayside.
Now, I am not sure how fast the reporting is, since we are no longer in the network (at least as far as I know). In any case, it did not feel like the earthquake that I felt years ago (about a 3 something) - no sway.
Was not like the sound and shake you get with a sonic boom. I am guessing some sort of explosion.
USGS, updates do not show anything for us.
Meteosat 14 km Water Vapor
(CIRA Personnel Only)
I would bid a 4 minimum :)
2260. atmoaggie
I have asked many times if the transitioning environment from La to EL was messing with the models. I got no answers,but it appears it may indeed be subjecting the code to that of which it is not prepared to handle. Just an ob from a newbie :)
Just stopping in to say that I will probably not be on the blog until the 26th July as the family is heading off to Vancouver tomorrow for an Alaskan cruise.
So, while I am gone PLEASE ensure there are no cyclones anywhere near the NW Caribbean OK ??? LOL
However, if I do see anything brewing I may check in via laptop from the ship !. This is such an awful addiction LMAO
Sure it wasn't a sonic boom? We've had several down here the past few days- the guys at Marine Air Corps Station Beaufort have been active lately with exercises.
You might confusing an observation of this years model results, under a different regime than recent years, with your own personal increasing level of awareness. And the El Nino, so far, is just barely an El Nino at all.
Hypothetical goofy BS: If anyone throws a few ice cube overboard, it will flip flop like a senator turned presidential candidate (pick any).
Thanks Keeper. At least there won't be any tropical cyclones in those fjords !
nice view of tropical atlantic - what do we think of our waves?
sorry link - Link
000
WTPZ45 KNHC 150244
TCDEP5
TROPICAL DEPRESSION FIVE-E DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052009
800 PM PDT TUE JUL 14 2009
THE CIRCULATION ASSOCIATED WITH THE SPRAWLING AREA OF LOW PRESSURE
TO THE SOUTH OF BAJA CALIFORNIA HAS BECOME BETTER DEFINED THROUGH
THE AFTERNOON...AS INDICATED BY VISIBLE IMAGERY AND A RECENT ASCAT
PASS. WHILE THERE IS LITTLE CONVECTIVE ORGANIZATION NEAR THE
CENTER...IT IS ORGANIZED INTO BANDS ON THE LARGE SCALE...WITH
SUFFICIENT ORGANIZATION TO WARRANT THE INITIATION OF ADVISORIES.
THE INITIAL INTENSITY IS SET TO 30 KT ON THE BASIS OF THE ASCAT
DATA.
THE INITIAL MOTION IS DIFFICULT TO DETERMINE SINCE THE CIRCULATION
CENTER HAS SO LITTLE HISTORY...BUT IS ESTIMATED TO BE 300/9. THE
ENVIRONMENT IS COMPLEX...WITH A RIDGE OF HIGH PRESSURE AT MID
LEVELS...AND A LOW AT UPPER LEVELS...LOCATED TO THE NORTH OF THE
DEPRESSION. THE FLOW ASSOCIATED WITH THE UPPER-LOW IS ENHANCING
CONVECTION TO THE NORTH AND EAST OF THE CENTER...AND THE CONVECTION
IS ASYMMETRIC ENOUGH TO PERHAPS CAUSE THE CENTER TO JUMP OR REFORM
TO THE NORTH OR EAST OVER THE NEXT DAY OR TWO. APART FROM THIS...A
GENERAL WEST-NORTHWESTWARD TRACK ALONG THE PERIPHERY OF THE
MID-LEVEL RIDGE IS EXPECTED FOR THE NEXT COUPLE OF DAYS BEFORE THE
SYSTEM WEAKENS OVER COOLER WATERS AND TURNS MORE WESTWARD WITH THE
LOWER-TROPOSPHERIC FLOW. THE OFFICIAL FORECAST LIES NEAR THE RIGHT
EDGE OF THE GUIDANCE ENVELOPE...CLOSE TO THE ECMWF...EARLY BUT THEN
FAVORS THE LEFT-LEANING GFS/GFDL/HWRF SOLUTION LATE IN THE FORECAST
PERIOD.
THE UPPER LOW IS CONTRIBUTING TO SOUTHWESTERLY SHEAR OVER THE
CYCLONE'S CENTER...AND THE CURRENT LIMITED CENTRAL ORGANIZATION OF
THE SYSTEM ARGUES AGAINST SIGNIFICANT STRENGTHENING. HOWEVER...THE
UPPER LOW IS FORECAST TO MOVE AWAY FROM THE DEPRESSION...WHICH
WOULD ALLOW FOR SOME DEVELOPMENT BEFORE THE SYSTEM ENCOUNTERS
COOLER WATERS IN 36-48 HOURS. THE INTENSITY GUIDANCE IS IN GOOD
AGREEMENT ON ONLY MODEST STRENGTHENING...AND THE OFFICIAL FORECAST
FOLLOWS SUIT.
FORECAST POSITIONS AND MAX WINDS
INITIAL 15/0300Z 13.8N 113.8W 30 KT
12HR VT 15/1200Z 14.8N 115.0W 35 KT
24HR VT 16/0000Z 16.4N 117.0W 40 KT
36HR VT 16/1200Z 18.0N 119.3W 40 KT
48HR VT 17/0000Z 19.0N 122.0W 35 KT
72HR VT 18/0000Z 20.0N 128.0W 30 KT
96HR VT 19/0000Z 21.0N 134.0W 25 KT...REMNANT LOW
120HR VT 20/0000Z 21.0N 140.0W 20 KT...REMNANT LOW
$$
FORECASTER FRANKLIN
kmanislander
Enjoy! We will hold off all storms.
WTPZ45 KNHC 150244
TCDEP5
TROPICAL DEPRESSION FIVE-E DISCUSSION NUMBER 1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP052009
800 PM PDT TUE JUL 14 2009
THE CIRCULATION ASSOCIATED WITH THE SPRAWLING AREA OF LOW PRESSURE
TO THE SOUTH OF BAJA CALIFORNIA HAS BECOME BETTER DEFINED THROUGH
THE AFTERNOON...AS INDICATED BY VISIBLE IMAGERY AND A RECENT ASCAT
PASS. WHILE THERE IS LITTLE CONVECTIVE ORGANIZATION NEAR THE
CENTER...IT IS ORGANIZED INTO BANDS ON THE LARGE SCALE...WITH
SUFFICIENT ORGANIZATION TO WARRANT THE INITIATION OF ADVISORIES.
THE INITIAL INTENSITY IS SET TO 30 KT ON THE BASIS OF THE ASCAT
DATA.
THE INITIAL MOTION IS DIFFICULT TO DETERMINE SINCE THE CIRCULATION
CENTER HAS SO LITTLE HISTORY...BUT IS ESTIMATED TO BE 300/9. THE
ENVIRONMENT IS COMPLEX...WITH A RIDGE OF HIGH PRESSURE AT MID
LEVELS...AND A LOW AT UPPER LEVELS...LOCATED TO THE NORTH OF THE
DEPRESSION. THE FLOW ASSOCIATED WITH THE UPPER-LOW IS ENHANCING
CONVECTION TO THE NORTH AND EAST OF THE CENTER...AND THE CONVECTION
IS ASYMMETRIC ENOUGH TO PERHAPS CAUSE THE CENTER TO JUMP OR REFORM
TO THE NORTH OR EAST OVER THE NEXT DAY OR TWO. APART FROM THIS...A
GENERAL WEST-NORTHWESTWARD TRACK ALONG THE PERIPHERY OF THE
MID-LEVEL RIDGE IS EXPECTED FOR THE NEXT COUPLE OF DAYS BEFORE THE
SYSTEM WEAKENS OVER COOLER WATERS AND TURNS MORE WESTWARD WITH THE
LOWER-TROPOSPHERIC FLOW. THE OFFICIAL FORECAST LIES NEAR THE RIGHT
EDGE OF THE GUIDANCE ENVELOPE...CLOSE TO THE ECMWF...EARLY BUT THEN
FAVORS THE LEFT-LEANING GFS/GFDL/HWRF SOLUTION LATE IN THE FORECAST
PERIOD.
THE UPPER LOW IS CONTRIBUTING TO SOUTHWESTERLY SHEAR OVER THE
CYCLONE'S CENTER...AND THE CURRENT LIMITED CENTRAL ORGANIZATION OF
THE SYSTEM ARGUES AGAINST SIGNIFICANT STRENGTHENING. HOWEVER...THE
UPPER LOW IS FORECAST TO MOVE AWAY FROM THE DEPRESSION...WHICH
WOULD ALLOW FOR SOME DEVELOPMENT BEFORE THE SYSTEM ENCOUNTERS
COOLER WATERS IN 36-48 HOURS. THE INTENSITY GUIDANCE IS IN GOOD
AGREEMENT ON ONLY MODEST STRENGTHENING...AND THE OFFICIAL FORECAST
FOLLOWS SUIT.
FORECAST POSITIONS AND MAX WINDS
INITIAL 15/0300Z 13.8N 113.8W 30 KT
12HR VT 15/1200Z 14.8N 115.0W 35 KT
24HR VT 16/0000Z 16.4N 117.0W 40 KT
36HR VT 16/1200Z 18.0N 119.3W 40 KT
48HR VT 17/0000Z 19.0N 122.0W 35 KT
72HR VT 18/0000Z 20.0N 128.0W 30 KT
96HR VT 19/0000Z 21.0N 134.0W 25 KT...REMNANT LOW
120HR VT 20/0000Z 21.0N 140.0W 20 KT...REMNANT LOW
My office overlooks the cruise ship tender dock. If you need some tips let me know.
nice view Savannah! What do we think? Still looks to have persistent convection.
Much appreciated !
Now you understand why I take the GFS with a gain of salt for cyclogenesis. It is a very good model for large scale synoptic forecasting... but the smaller you get, the more problems you are likely to have. Also, keep in mind it is a *global* model. It can only have so much resolution and capabilities. It can sometimes be a "canary in a coal mine", but it can also just as easily be completely out to lunch on cyclogenesis. Once a storm is spinning though, it is fairly good, since it then becomes a known quantity, with a smaller range of uncertainty.
Hey kman, I notice that like other tropical entities u are moving from the tropics to the poles. . . . nice cross-continent transition without losing your conformation or having to change ur name to a EPac one....
lol
Have a great time!
It's hard to say, but there is obviously a lot of vorticity in that system. Too bad the Quickscat missed it on both the ascending and descending passes. Once we get a good Quikscat we'll have an idea of what's going on at the surface, if anything.
There's still some dry air and dust about, but the wave ahead of it significantly cleared its path.
Yep, carrying the heat to the North . Can't wait for all that smoked salmon and booze LOL
Ah, the Butterfly effect :)
Have a good and safe trip Kman! Say Hi to Orca I think he is up that way.
Will do and thanks. Got my glacier gear packed.
Actually I have a whale watching trip booked. You don't suppose I might see him do you ??
P.S. Have a great trip, kman!
And one of my sons. The other son left for the UK today.
First vacation since last December so very much looking forward to it.
Looks like the tropics will be quiet until August which would be just fine by me.
Unless it is a small storm, in which case it doesn't perform so well.
And don't bash global, only by name and coverage. The Japanese have developed a global model of higher spatial resolution that resolves clouds (and I think it explicitly carries out cloud calculations) that has been able to correctly model the MJO a few weeks out, spin up a TC at the right time, and model its track and intensity quite well. Called NICAM. One version here: http://www.ccsr.u-tokyo.ac.jp/~satoh/nicam/index.html
We just need that model, and others similar, to get to the operational stage.
Dmax around 11-4 right? Not sure - we really need a Quickscat pass to really tell if it is developing.
Don't be surprised if I check in from the chilly North .
Viewing: 2251 - 2301
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