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Carolina and summarizes the results of four studies that provide data on the rates of relative sea level rise in (Box 3 -2). The data analyzed in the report indi- cates that relative sea level rise varies as a function of latitude, with higher rates in the north as a result of local geology and differences in crustal subsidence and uplift (NCCRC 2010). The first three studies listed in Box 3 -2 utilize geological data and provide the basis for understanding the potential for future changes in the rate of sea level rise. Based on these studies, the panel made projec- tions for relative sea level rise in North Carolina through 2100 based on differing rates of sea level rise acceleration (Figure 3 -9). The initial rate of rise was set at 4.27 mm per year ( Zervas 2004) with a minimum rise of 0.50 meters to a maximum of 1.4 meters by 2100. Delayed positive feedback may result in an underestimation of the contribution from land use resulting in a total sea level rise above 1.4 meters (NCCRC 2010). Given the uncertain- ty and potential increase in ice sheets melting and contributing to sea level rise the panel concluded that 2 meters of sea level rise, by 2100 is unlikely, but still possible, and could occur only with rapidly accelerated and very high rates of warming and ice sheet melting (NCCRC 2010). Box 3 -2. Four studies summarized in the North Carolina Sea -Level Rise Assessment Report that provide data on relative sea level rise in North Carolina (Source: NC Coastal Resources Commission 2010). Study 7: Horton et al. (2009) developed a sea -level database for North Carolina from new, published and unpub- lished geological data that cover the past 12,000 years. During this period, long -term average rates of SLR varied from approximately 5 mm per year (19 inches /century) until approximately 3,500 y BP (y BP — years before present, where "present" is AD 1950), to about 1 mm per year (4 inches /century) from 3,500 y BP until today. Study2: Kemp (2009 thesis) presented continuous, high resolution constructions of SLR in North Carolina for the past 2,000 years using geological data from Sand Point (Roanoke Island) and Tump Point (Cedar Island).The rate of RSL rise was close to 1 mm per year (4 inches /century) for most of this period. The rate almost doubled to 1.7mm per year (6.7 inches /century) for about 350 years during the Medieval Warm Period (AD 1000 to 1350), and then returned to 1.0 mm /yr for the next few centuries.The rate then increased in the 20th century to about 3.2 mm per year (12.6 inches /century). Study 3: Kemp et al. (2009) concentrated on the RSL records at Sand Point and Tump Point since AD 1500. They noted that the 20th century rate of RSL rise of 3.0 to 3.3 mm per year (13 inches /century) is in agreement with local tide gauges (Fig. 1) and instrumental records from the north -west Atlantic (Woodworth et al., 2008). Study4: Zervas (2004) documented the MSL trends for eight water level stations in North Carolina (Table 1). The intervals of time represented by the data vary from station to station and dredging has resulted in variation in the trends of different tidal datums. These factors led Kemp et al. (2009, Study 3) to average North Carolina tide gauge records. The highest rates (up to 16.8 inches /century) are in the northern portion of the state. Chapter 3: Projected Impacts of Climate Change in North Carolina 67