Sea Level Rise, Hurricanes, Coastal Adaptation

1. Sea Level Rise, Hurricanes, Coastal Adaptation Peter Webster

2. Sea Level Rise Red: sea level rise ca. 2100 Blue: storm surge major hurricane IPCC indicates likely [>66%] increase of 1-2 feet by 2100 (does not include accelerated or catastrophic melting of ice sheets) Recent estimates: 1.4 m rise by 2100 is plausible

3. IPCC AR4: Hurricanes WMO UNEP • There is observational evidence for an increase of intense tropical cyclone activity in the North Atlantic since about 1970, correlated with increases of tropical sea surface temperatures (SST) • It is likely [>66%] that future tropical cyclones will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs

4. Intensity Distribution of North Atlantic Tropical Cyclones Since 1995, there has been a shift in the intensity distribution towards more major hurricanes

5. Increased tropical cyclone activity since 1970, correlated with increasing sea surface temperatures

6. Climate model projections of future hurricane activity • For a 2.5oC (5oF) temperature increase: • • 0-30% increase in number of North Atlantic tropical • cyclones • • 10% increase in tropical cyclone intensity • equivalent to 33% increase in damage • 30% increase in the number • of major hurricanes

8. 3 major hurricanes struck GA coast in the 1890’s

9. Oct 1898 – Georgia Hurricane Landfall near Brunswick as a Cat. 4 with max winds of 135 mph 180 dead; $56.5 million in damage (2004 dollars) Max storm surge was 13-18 ft. in Darien http://www.srh.noaa.gov/jax/research/hurricanes/history/1898/

10. Risks to Coastal Georgia • 3 major landfalls in the 1890’s (but none since 1900) • Potential for big storm surge owing to shallow shelf • Barrier islands at extra risk associated with sea level rise

11. Impacts of floods • Immediate impacts: property damage, injuries, death • Health issues: infectious diseases, exposure to toxins • Key water quality issues: • Floodwater tainted with raw sewage, pesticides, agricultural waste, petroleum products, dead animals • Flooding of animal waste retention pools from hog, cattle, dairy, poultry farms Hurricane Frances (2004) caused $41M damage to Atlanta from flooding

12. Case Study: Hurricane Ivan (2004) From National Climatic Data Center Satellite Archives • Category 3 hurricane that made landfall just west of Gulf Shores, AL • Produced 25 tornadoes in GA resulting in 2 deaths and 10 injuries. • Rainfall in excess of 5 to 10 in. and high winds destroyed 50% pecan and 15% cotton crop in GA. • Property damage in GA $68.8 M.

13. Hurricane Risks to Georgia • While no major hurricane strikes since 1900, increases in # of Atlantic storms increases the probability of a GA landfall • Landfall on GA coast has potential for big storm surge owing to shallow shelf • Barrier islands at extra risk associated with sea level rise • Heavy rainfall associated with storms that make landfall in the Gulf; rainfall in hurricanes is expected to increase • Tornadoes likely to be spawned in GA by increasingly intense storms that make landfall in the Gulf

14. Adaptation Strategies • Coastal ecosystems will eventually adapt, • but hurricanes will cause short term • damage to maritime forests, wetlands • marshes, and wildlife disruptions • Human systems will face shoreline erosion, loss of beaches • and dunes, damage to structures, economic losses. Adaptation strategies include: • Land use • Coastal engineering • Building codes • Wetlands preservation • Forest preservation