Red Track (C-31): Sea Level Rise and Extreme Weather (Afternoon)

- Session Description (click to collapse)

Sea levels have been rising for over the 6000 years since the last ice age.   Current  worldwide sea level rise estimates are  1.8 mm/year, with local sea level rise varying according to  factors such as local glacial isostatic adjustments and other land movements.

Warming of the atmosphere and the oceans creates drivers for increasing the rate of sea level rise.  Melting of glaciers and ice sheets leads to a eustatic rise of sea level, while the warming of the ocean water results in its expansion, leading to a steric sea level rise.  The Intergovernmental Panel on Climate Change (IPCC), a worldwide collection of climate scientists, in 2007 has provided a range of sea level predictions for the next 100 years that exceed the current trend. 

Atmospheric and ocean warming is presumed to lead to increases in storminess and larger wave heights.  Increased storms (magnitude and frequency), with associated larger waves and water levels, would result in larger coastal disasters, exacerbated by increasing coastal populations.

Data gaps include behavior of large ice sheets and climate effects on meteorology.

Recommended Readings

- Moderator (click to collapse)

Tony Dalrymple

Tony Dalrymple is the Willard & Lillian Hackerman Professor of Civil Engineering in The Johns Hopkins University’s Department of Civil Engineering. He teaches classes in coastal engineering, civil engineering analysis, and coastal modeling. His research interests include wave mechanics, fluid mechanics, littoral processes, tidal inlets, nearshore hydrodynamics, and coastal processes.

Dr. Dalrymple is a member of the National Academy of Engineering and the National Research Council’s (NRC’s) Committee on Sea Level Rise in California, Oregon, and Washington; the NRC’s Committee on U.S. Army Corps of Engineers Water Resources Science, Engineering, and Planning; the Coasts, Oceans, Ports, and Rivers Institute (COPRI) Coastal Engineering Research Council; and the American Society of Civil Engineers. He has been interviewed by numerous media outlets, including The New York Times (for an article on the New Orleans levees) and CNN (to discuss the 2004 Indian Ocean earthquake and tsunami).


Ph.D., Civil and Coastal Engineering, University of Florida, 1973
M.S., Ocean Engineering, University of Hawaii, 1968
A.B., Engineering Sciences, Dartmouth College, 1967

- Notes (click to collapse)

People that attended:

John Schloman – APL, modeling and simulation

Prof. Tony Dalrymple - Moderator/Chair

Ben Hobbs – Director of E2HSI, Prof of Engineering

Linda Guilnof – Prof @ Earth and Planetary Sciences @ Homewood

Haiou Huang – PhD in Global Water Program, research staff @ JHSPH, interested in water treatment

Mary McCarthy – finishing MBA @ George Mason, also does work w/ MD dept of Natural Resources

Maio sirensen – Recent graduate from SAIS, general interest

Stuart Chaitkin – Prof @ JHSPH, interest in Energy policy, general interest w coastal issues

Brenda Afzal – Community public health nurse, US climate policy coordinator

Janet Driffy – Dept of Veterans Affairs,

Andrew Blohm – Research for UMD

Gabriella , Resources for the future Think-tank

Peter McCullough – Works for space telescope institute @ JHU, personal interest





Sea Level Rise: 120m in 20,000 years

6k years ago sea level rise is rather slow on global scale (couple of mm per year)


Local sea level rise (aka relative sea level rise)

Effects due to land motion: tectonic effects, post glacial isostatic rebound, anthropomorphic effects (the effects we make-oil/gas/water extraction), consolidation


2000 tide gages around the world (Permanent service for mean sea level)

Gages concentrated in northern hemisphere – often need to decipher the signal that comes across with regards to annual sea level rise

Don’t have a uniform distribution of tide gauge samples.


2 important corrections to account for: glacial isostatic adjustment (what the glaciers are doing, GPS (looking at changes in land)


Satellites show sea level trends as well: TOPEX/POSEIDON

Can be pretty spotty due to freshwater trends, wind patterns changing, things happening on decayal scales (EL NINO and La Nina) i.e. natural oscillations of the earth


Satellite Topex/Poseidon and Jason-1 – trying to correct out for atmospheric pressure as well


Projecting global sea level rise - GCM models and models of the atmosphere – running giant models, calibrate to past and try and project into the future

Issues around melting glaciers and ice sheets


Comparing satellite observations to IPCC projections seems to be tracking @ upper end of IPCC projections


Other ways to estimate what’s happening in future – leading way is Rahmstorf (2007) – Rate of SLR = a(T-T0), proportional to temperature

Vermeer and rahmstorf (2009) – Rate of SLR = a(T-T0) + b dT/dt, adding instant response


Vermeer and rahmstorf (2009) – basically say SLR is projected to be much more

Approximately on the high end is 1.6 meters SLR.


IPCC uses collection of General Circulation Models and integrates them to predict steric and eustatic rise.

GRACE satellite – measuring mass of the earth, looking @ local gravity effects, how much ice has been lost with time?

Problem: People that do ice don’t know how much volume of ice is on the earth (what’s under the ice sheets, what is the depth of the valleys).


Weakness and data gaps:

Ice dynamics – what we know is based on very few data points

Circulation models (AOGCM) – weaknesses in modeling, in parameters (i.e. how does the vegetation get parametized (i.e. carbon uptake of plants)?), all don’t give the same answers

Increased storminess – in terms of storm surge and catastrophic impact of high winds. How much of this is going to occur?

Data errors – how well do we model the earth to correct tide gauges, how accurate is GPS? Do the errors compound?


Responses to local sea level rise:

Harbor infrastructure

 coastal communities (shoreline recession greater than sea level rise i.e. inundate and then erode) – sand renourishment costs millions of dollars in doing it, tend to do more each time we do it, process that is getting more and more expensive, do we retreat communities or do we try and armor communities- retreat, armor or do nothing

Coastal transportation: vulnerability for highways, etc. coastal infrastructure in general what are we going to do

Wetlands: Louisiana loses almost 30 sq miles of wetlands per year- going on for about 100 years. Wetlands around USA are getting smaller and smaller, what are we doing about saving them?

Salinity intrusion: As salt water gets higher it’s going to into estuaries and aquifers


More than just inundation there is also erosion that has to be considered with regards to sea level rise.



MD SLR area in the last 50 years is about half a foot.

Eastern shore – 10 meters recession per year due to SLR

Beach nourishment is a fix to beach erosion – costs ~ million dollars but economic revenue generated by this is much bigger (big tax income from tourists)

Have shore erosion maps shown to people buying real estate, that way coastal land owners will know projections for SLR and may make better informed decisions with regards to purchasing real estate on the coast.

Buyouts/zoning is still somewhat of a foreign concept. Needs to be stronger input from state and local govt’s to zone and restrict building/housing locations.

Screen decisions to see which things we’ll have to live with and what we need to act upon.

Public perception is something that seems to be ignored and the power it has to influence the things we are trying to do.

Need to do a better job of translating science into the public to get more buy in.

Infrastructure planning should have an environmental impact assessment and climate adaptation assessment so that there is better documentation on this process and a more comprehensive plan is put forth.

In Bermuda, they don’t build by the coast – they let the risk define the cost.

Can’t attribute recent hurricanes to climate change – Lawrence Buja – hurricane people he does know thinks they are stronger, which makes sense with the physics

Not really known if there is a state by state study of vulnerability based upon SLR.

Army is very concerned w/ building strategies to account for SLR, not really sure what numbers to use, but they are very concerned and very interested.

Navy is taking very high SLR estimates; think it is approximately 2 meters.

Rate of rise on west coast has sort of leveled out, but where is the water going to go, is there going to be a much quicker rise? This may have something to do with the wind circulation patterns – Asia experiencing higher sea level rise.

Adaptation is probably the primary option with mitigation as the long term option.

There needs to be more education in school system early on that science is experimentally based.

Across any of the projections, the uncertainty between the scenarios is much greater.

Social uncertainties, qualitative uncertainties (i.e. methane release) are things we are unsure of.

Integrate with educators as well – Thereby passing on concerns, information, etc on to the youth. Also, should pass this on to the elementary level as well. Need to translate science into public knowledge and link this knowledge to personal behavior (i.e. application)



Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Polar ice cap contributions by Linda.Hinnov
Extreme Ice Survey by John Schloman
gyre effect? by Linda.Hinnov