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Regional Climate Change Effects: Useful Information for Transportation Agencies

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Figure 1 Text

This figure depicts relative sea-level changes experienced on U.S. Coastlines between 1958 and 2008. The figure is a satellite photograph of North America, Hawaii, and Central America. Sea-level changes are indicated on the map by arrows of different sizes and colors. Larger arrows indicate sea level changes of a higher magnitude (over 8 inches at the largest), and the smaller arrow sizes indicate smaller changes (0 to 2 inches at the smallest). Sea level rises are indicated by red and orange arrows and decreases are indicated by blue arrows. Looking at the satellite photograph, there are several large red arrows on the Gulf Coast indicating 8 inches of rise and about 20 medium sized red arrows of approximately 4 to over 6 inches of rise for much of the entire east coast of the U.S. The greatest rise is evident over the Mid-Atlantic region. There are also four small orange arrows indicating 4 inches or less of rise on Hawaii. There are 10 arrows demonstrating sea level change along the west coast of the U.S. The southern coastline for the west coast has four small yellow arrows of less than 2 to 4 inch rise. The northern coastline for the west coast has 6 arrows signifying varying direction of sea level change from a 6 inch fall to a 6 inch rise. The southern Alaskan coast has both large red and large blue arrows representing a change of sea level from 8 inch rise to over 8 inch fall. This distribution of arrows indicates that the largest relative sea level rises have occurred along the Gulf Coast with substantial rises also occurring along the east coast of the U.S. Sea level changes in Alaska have been large but mixed and sea level changes along the west coast of the U.S. have been relatively small.
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Figure 2 Text

This figure describes the process of creating the mean, likely, and very likely ranges from the USGCRP data. The figure depicts two bell curves, a blue one labeled "Scenario B1" and a green one labeled "Scenario A2." The two curves overlap and the two peaks, representing the mean values, are next to each other. A bracket indicates that the distance between the mean value from Scenario A2 and mean value from Scenario B1 is the "mean range." Both the Scenario B1 and the Scenario A2 curves also have lines indicating the range of values designated as either likely or very likely. The likely band for each scenario is defined as one standard deviation from the mean. The overall likely range bracket starts at the lowest end of likely ranges for either Scenario B1 or Scenario A2 curves and ends with the highest end of the likely ranges for either Scenario B1 or Scenario A2 curves. The very likely range is defined as two standard deviations from the mean. The overall very likely range is defined as the combination of very likely ranges from the two scenario curves.
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Figure 3 Text

This figure illustrates the criteria used to assess whether a study is included in the narrative regional discussions. The first criteria reads, "Was the study conducted recently (e.g., post 2003)?" If not, the study was not included. If the study was conducted after 2003, the reader proceeds to the second criteria, which reads, "Does the study include a number of climate models (optimum models if identified for that region)?" If not, the study was not included. If the study does include multiple climate models, then the reader proceeds to the third criteria, which reads, "Does the study include relevant emissions scenarios?" If not, the study was not included. If the study did include relevant emissions scenarios, then the reader proceeds to the final criteria, which reads, "Is the data at the regional-scale or downscaled for finer spatial scale results?" If not, the study was not included. If the study contained data at the regional-scale and fulfilled all four criteria, then it was included in the regional discussion.
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Figure 4 Text

This figure presents four maps of the United States which illustrate projected mean summer temperature change (degrees Fahrenheit) relative to the historical time period of 1971 to 2000. The projections are derived from statistically downscaled CMIP3 projections. The top two maps represent projected temperature changes based on the A2 emission scenario, one map is for mid-century time period (2040-2069) and the second map is for end-of-century time period (2070-2099). The bottom two maps represent projected temperature changes based on the B1 emission scenario for the mid-century time period (2040-2069) and the second map illustrates projected temperature changes for the end-of-century time period (2070-2099). In both the A2 and B1 maps, the end-of-century projections show more severe temperature increases of approximately 5 to 10 degrees Fahrenheit. In addition, the A2 maps illustrate the high-end temperature increases throughout the country evident with bright red coloring. The mid-century A2 and B1 maps illustrate projected temperature changes from 1 to 6 degrees Fahrenheit represented by light orange and yellow coloring. The lowest temperature increases is associated with the B1 mid-century map. All four maps indicate that the temperature increases are the least severe in the Pacific Northwest and along coastal areas. In general, the greatest temperature increases are noticeable for portions of the Southwest, around the Great Lakes, and the Northeast for the B1 scenario. The greatest temperature increases for the A2 scenario is evident for the Southwest, Great Plains, and the Northeast.
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Figure 5 Text

This figure is a map of the world that illustrates local sea level change in meters due to ocean density and circulation change relative to the global average. Positive changes of above 0.0 to 0.3 meters above the global average are indicated on the map with warm colors (yellow, orange and red). Sea level fall relative to the global average of below 0.0 to 0.3 meters are indicated with cool colors (blue and light blue). Positive values indicate greater local sea level change than global during the 21st century. The northern, artic region of the map contains the most red, indicating sea level increases of around and above 0.2 meters. The majority of the ocean is colored either green or yellow, indicating changes of negative 0.05 to positive 0.05 meters. Most of the oceans surrounding Africa are yellow whereas most of the oceans to the west of South America and North America are green. The local sea level changes were calculated as the difference between averages for 2080 to 2099 and 1980 to 1999, as an ensemble mean over 16 AOGCMs forced with the SRES A1B scenario. Stippling denotes regions where the magnitude of the multi-model ensemble mean divided by the multi-model standard deviation exceeds 1.0 (IPCC 2007). The stripping is evident off for a small portion off the western south american coast, around the waters of Antartica, along the northwestern African coast. This figure does not include other local factors such as land uplift or subsidence.
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Figure 6 Text

This figure demonstrates the large local variability in extreme heat events projected to occur at the end of the century for the contiguous United States. The figure contains a map of the United States with colors indicating the locations of projected days occurring at or above 90 degrees Fahrenheit. The time period for the projection is 2080-2099 and the projections are based on Scenario A2. In general, the northern sections of the United States are colored dark or light green, indicating that between 75 and 90 days will be at or above 90 degree Fahrenheit. The southern sections of the United States range from yellow around southern Illinois, Missouri and Kansas to red in the Florida and Gulf Coast region. The yellow colors indicate 105 to 120 days at or above 90 degrees Fahrenheit, while the red colors indicate 135 to 160 days at or above 90 degrees Fahrenheit. The west coast contains a much more complex pattern of colors than the rest of the country, indicating that temperature patterns are very local. For example, there are areas of dark blue throughout the Rocky Mountain region, indicating that in those areas there will be approximately 15 days at or above 90F at the end of the century. Nearby, in southern California, there are also areas of bright red, indicating areas where there are projected to be over 135 days at or above 90 degrees Fahrenheit.
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Figure 7 Text

This figure illustrates projected changes in precipitation by 2080-2099, relative to average seasonal precipitation in 1961-1979 under the A2 emission scenario as simulated by 15 climate models. The figure presents four different maps of the United States, each representing a different season. Dark brown to light brown colors indicate a decrease in precipitation of between 40% (dark brown) to 5% (very light brown). Dark blue to light blue colors indicate an increase in precipitation of between 40% (dark blue) to 5% (light blue). The colored maps indicate that the most widespread decreases in precipitation will occur in the summer, particularly in the Pacific Northwest (-35 to 10%), in the very southern tip of Florida (around -30%) and in the southern Midwest (-25% to -10%). There will also be severe decreases in precipitation in the winter and spring in the southern United States and in Mexico. In the spring, projected decreases range from -40% to -30% in southwest California, Nevada and northwestern Mexico with additional increased dryness expected across the entire southern United States. The pattern is similar, although less severe in the winter map. The fall map displays the least change in precipitation, with only moderate decreases in precipitation expected in the Great Plains Region, the Caribbean and portions of northern Mexico. Both the winter and spring maps illustrate that precipitation is expected to increase throughout Canada and the northern United States by between 5% and 30%. Larger increases are concentrated in the very northern areas of Canada, with only small increases predicted in the Northern United States for these seasons. In the summer and fall, projected increases in precipitation are only evident in the very northern areas of Canada. The hatched areas on the maps demonstrate projections where confidence is highest (that is, at least two out of three models agree on the sign of the projected change in precipitation). Overall, confidence is higher for the winter and spring seasons where the northern regions are projected to experience significantly more precipitation in response to the northward movement of the boundary between warm, moist southern air and cold, continental northern air.
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Figure 8 Text

This figure contains three maps illustrating the number of days per year projected to be at or under 32 degrees Fahrenheit for the Great Lakes region of the United States. The three maps are based on 16 multi-model ensemble averages for years 1961-1979, 2040-2059, and 2080-2099 for Scenario A2. The map to the farthest left is for 1961 to 1979 and illustrates that southern Canada and the northern portions of Minnesota and Wisconsin experienced between 180 and 200 freezing days per year, while more southern states experienced between 100 and 120 freezing days. The middle map is for 2040 to 2059 and the number of freezing days projected has declined for all areas, so that only the very northern portions of Minnesota and southern Canada are projected to experience more than 200 freezing days per year. The third map is for 2080 to 2099 and the projected number of freezing days has declined even further, so that most of Indiana, Illinois, Missouri and Iowa are projected to only experience 80 to 100 freezing days. In this map of end-of-century conditions, Minnesota and Wisconsin are projected to experience between 120 and 140 freezing days, with southern parts of Canada expected to experience 180 freezing days.
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Figure 9 Text

This figure illustrates the geographic variability of heat events across the Southwest United States in the time periods 1961 to 1979 and 2080 to 2099. The figure contains two maps with warm and cool colors indicating areas of projected temperature changes. The map to the left is for 1961 to 1979 and is shaded blue, indicating that the majority of the area experienced less than 15 days at or above 90 degrees Fahrenheit. The exception is the area where Southern California borders western Nevada and northern Mexico. This area of the map is shaded red and dark red, illustrating that this area experienced 150-180 days at or above 90 degrees Fahrenheit per year. The map to the right is for the end-of-century period, and indicates that the western United States will experience a high level of variability in number of hot days, as indicated by the complicated color patterning across the region. Southern California, western Nevada and Northern Mexico are shaded a dark purple color, indicating that the region is projected to experience 180 days per year over 2080-2099. Areas throughout the Rocky Mountain region vary in color, but indicate overall that there will be a higher number of hot days per year as compared to the 1961-1979 time period.
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Figure A-1 Text

This figure illustrates the criteria used to assess whether a study is included in the narrative regional discussions. The first criteria reads, "Was the study conducted recently (e.g., post 2003)?" If not, the study was not included. If the study was conducted after 2003, the reader proceeds to the second criteria, which reads, "Does the study include a number of climate models (optimum models if identified for that region)?" If not, the study was not included. If the study does include multiple models, then the reader proceeds to the third criteria, which reads, "Does the study include relevant emissions scenarios?" If not, the study was not included. If the study did include relevant emissions scenarios, then the reader proceeds to the final criteria, which reads, "Is the data at the regional-scale or downscaled for finer spatial scale results?" If not, the study was not included. If the study contained data at the regional-scale and fulfilled all four criteria, then it was included in the regional discussion.
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Updated: 03/27/2014
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