The Challenge of Projecting Future Sea
Levels in the Chesapeake Bay Region
Severn River Association
February 18, 2014
Donald F. Boesch
2008 Climate Change Impact Assessment
climatechange.maryland.gov
MVN RSM Program
Climate Action Plans
climatechange.maryland.gov
MVN RSM Program
Updating SLR Projections
climatechange.maryland.gov
MVN RSM Program
Sea Level Had Been Stable 2000 Years
meters
0.4
Tide gauges
0.2
0.0
-0.2
Paleo-reconstruction
-0.4
Kemp et al. 2011. Proc. National Acad. Sci
MVN RSM Program
Global Mean Sea Level by Satellite
Altimeter
sealevel.colorado.edu
MVN RSM Program
What Causes Sea Level To Change?
MVN RSM Program
World Ocean is Warming
MVN RSM Program
Polar Ice Sheet Loss
Velicogna 2009 GRL
MVN RSM Program
9
9
NRC Global Sea-Level Rise Projections
global mean sea level rise from 2000
best estimates
National Research Council. 2012. Sea-Level Rise for the Coasts of
California, Oregon and Washington: Past, Present and Future.
MVN RSM Program
Fingerprints of Polar Ice Sheet Melting
Greenland
West Antarctica
MVN RSM Program
Do You Have A Sinking Feeling?
Early Interglacial
The glacial
forebulge
collapses
and land
surface
subsides
Late Interglacial
Florida
Maryland
New York New England
MVN RSM Program
Slowing of Gulf Stream Raises Sea Level
Tide gauge level trends
Gulf Stream strength
Based on work of Tal Ezer and
colleagues, Old Dominion University
J. Geophysical Research 118:685
MVN RSM Program
How Much Will Sea Level Rise
in Maryland?
MVN RSM Program
Sea-Level Rise Will Not Stop in 2100
stabilizing at 2ºC
ending all emissions
in 2016
Schaeffer et al. 2012 Nature Climate Change 2: 867.
MVN RSM Program
Intergovernmental Panel on
Climate Change 5th Assessment
It is extremely likely that
human influence has been
the dominant cause of the
observed warming since the
mid-20th century.
Limiting climate change will
require substantial and
sustained reductions of
greenhouse gas emissions.
www.ipcc.ch
MVN RSM Program
How Much Has It Warmed?
Global average
land and ocean
temperature
www.ipcc.ch
about 0.9°C
or 1.6°F
MVN RSM Program
How Much Will it Warm?
It mainly depends on how much greenhouse gases we emit.
Global average surface temperature
7.2°F
3.6°F
www.ipcc.ch
RCP8.5 = ‘business as usual’ continued growth in emissions
MVN RSM Program
RCP2.6 = rapid reductions in GHG emissions to 0 by 2070
How Much Will the Seas Rise?
Unlike temperature, sea
level rise does not
stabilize during century
www.ipcc.ch
MVN RSM Program
Elicitation of Estimates by Experts
MVN RSM Program
Global Mean Sea-Level Rise (meters)
0.5
0
2050
Expert elicitation
Expert elicitation
Unrestrained Drastic
emissions reductions
5%
17%
17%
83%
83%
Expert elicitation
IPCC
95%
Expert elicit.
IPCC
NRC 2012
1.0
IPCC
IPCC
NRC 2012
1.5
95%
5%
Unrestrained Drastic
emissions reductions
MVN2100
RSM Program
Maryland
2
New Jersey
3
New Jersey
4
Maryland
Relative Sea-Level Rise (feet)
5
1
2050
Miller et al. 2013. AGU Earth’s Future
2100
MVN RSM Program
Consequences of Sea-Level Rise
Light blue: salt marshes
Greens: < 2 m, susceptible to innundation
Orange-yellow: 2-4 m,
susceptible to storm
surge
Greater Bay volume,
ocean
influence
MVN
RSM Program
Tidal Wetlands and Sea-Level Rise
Human activities have
significant consequences
for stability
Kirwan & Megonigal 2013. Nature 404:53
MVN RSM Program
Questions or Comments?
boesch@umces.edu
www.umces.edu/people/president
@DonBoesch