--- - attributes: ~ caption: "These maps show current population along with population projections by county for the year 2100. Projected populations are based on Shared Socioeconomic Pathways (SSPs)—a collection of plausible future pathways of socioeconomic development.{{< tbib '8' '9c909a77-a1d9-477d-82fc-468a6b1af771' >}} The middle map is based on demography consistent with the SSP2, which follows a middle-of-the-road path where trends do not shift markedly from historical patterns. The bottom map uses demography consistent with SSP5, which follows a more rapid technical progress and resource-intensive development path. Increasing urban populations pose challenges to planners and city managers as they seek to maintain and improve urban environments. Data are unavailable for the U.S. Caribbean, Alaska, and Hawai‘i & U.S.-Affiliated Pacific Islands regions. Source: EPA" chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2017-08-02T12:13:45 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/iclus-2100-population-projections---ssp2-and-ssp5.yaml identifier: iclus-2100-population-projections---ssp2-and-ssp5 lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 1 report_identifier: nca4 source_citation: ~ submission_dt: 2018-12-03T17:09:56 time_end: ~ time_start: ~ title: Current and Projected U.S. Population uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/iclus-2100-population-projections---ssp2-and-ssp5 url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: 'Projected increases in the number of very hot days (compared to the 1976–2005 average) are shown for each of five U.S. cities under lower (RCP4.5) and higher (RCP8.5) scenarios. Here, very hot days are defined as those on which the daily high temperature exceeds a threshold value specific to each of the five U.S. cities shown. Dots represent the modeled median (50th percentile) values, and the vertical bars show the range of values (5th to 95th percentile) from the models used in the analysis. Modeled historical values are shown for the same temperature thresholds, for the period 1976–2005, in the lower left corner of the figure. These and other U.S. cities are projected to see an increase in the number of very hot days over the rest of this century under both scenarios, affecting people, infrastructure, green spaces, and the economy. Increased air conditioning and energy demands raise utility bills and can lead to power outages and blackouts. Hot days can degrade air and water quality, which in turn can harm human health and decrease quality of life. Sources: NOAA NCEI, CICS-NC, and LMI.' chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2017-05-31T20:28:19 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/heat-projections-for-msas.yaml identifier: heat-projections-for-msas lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 2 report_identifier: nca4 source_citation: ~ submission_dt: 2018-12-03T19:09:17 time_end: ~ time_start: ~ title: Projected Change in the Number of Very Hot Days uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/heat-projections-for-msas url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: 'Many U.S. cities are projected to see more days with heavy precipitation, increasing the risk of urban flooding, especially in areas with a lot of paved surfaces. Projections of percent changes in the number of days with heavy precipitation (compared to the 1976–2005 average) are shown for each of five U.S. cities under lower (RCP4.5) and higher (RCP8.5) scenarios. Here, days with heavy precipitation are defined as those on which the amount of total precipitation exceeds a threshold value specific to each city. Dots represent the modeled median (50th percentile) values, and the vertical bars show the range of values (5th to 95th percentile) from the models used in the analysis. Modeled historical values are shown for the same thresholds, for the period 1976–2005, in the lower left corner of the figure. Historical values are given in terms of frequency (days per year) and return period (average number of years between events). Sources: NOAA NCEI, CICS-NC, and LMI.' chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2018-04-03T15:48:15 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/projected-change-in-precipitation.yaml identifier: projected-change-in-precipitation lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 3 report_identifier: nca4 source_citation: ~ submission_dt: 2018-12-03T19:09:29 time_end: ~ time_start: ~ title: Projected Change in Number of Days with Heavy Precipitation uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/projected-change-in-precipitation url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: "These images show surface temperatures of playground equipment in metropolitan Phoenix, Arizona. Children are particularly susceptible to high heat{{< tbib '12' 'f1e633d5-070a-4a7d-935b-a2281a0c9cb6' >}} and can be exposed through daily activities. (A) A slide and dark rubber surface in the sun (orange/red colors are shown reaching temperatures of 71°C [160°F] and 82°C [180°F], respectively. The blue/green colors are under a shade sail. (B) Playground steps made of black powder-coated metal are shown reaching a temperature of 58°C (136°F) in the direct sunlight. Images use infrared thermography and were taken mid-day on September 15, 2014. Credit: Vanos et al. 2016.{{< tbib '49' '25f43b4b-e8eb-4daa-8c9b-cf0991f72c6d' >}}" chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2018-04-03T20:08:58 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/extreme-heat-photo.yaml identifier: extreme-heat-photo lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 4 report_identifier: nca4 source_citation: ~ submission_dt: 2018-11-30T15:27:56 time_end: ~ time_start: ~ title: Threats from Extreme Heat uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/extreme-heat-photo url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: 'Flash flooding overwhelmed drainage systems and swamped roadways in Pittsburgh, Pennsylvania, in 2011. The flooding disrupted businesses and commutes, damaged homes, and caused four deaths. Photo credit: Pittsburgh Post-Gazette.' chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2018-04-03T20:09:44 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/flash-flooding-photo.yaml identifier: flash-flooding-photo lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 5 report_identifier: nca4 source_citation: ~ submission_dt: 2018-11-30T15:27:58 time_end: ~ time_start: ~ title: Flash Flooding Impacts Urban Infrastructure and Well-Being uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/flash-flooding-photo url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: 'With heavy downpours increasing nationally, urban areas experience costly impacts. (top) In cities with combined sewer systems, storm water runoff flows into pipes containing sewage from homes and industrial wastewater. Intense rainfall can overwhelm the system so untreated wastewater overflows into rivers. Overflows are a water pollution concern and increase risk of exposure to waterborne diseases. (bottom) Intense rainfall can also result in localized flooding. Closed roads and disrupted mass transit prevent residents from going to work or school and first responders from reaching those in need. Home and commercial property owners may need to make costly repairs, and businesses may lose revenue. Source: EPA.' chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2017-08-02T15:02:54 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/cascading-consequences-of-heavy-rainfall-for-urban-systems.yaml identifier: cascading-consequences-of-heavy-rainfall-for-urban-systems lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 6 report_identifier: nca4 source_citation: ~ submission_dt: 2018-11-30T15:28:00 time_end: ~ time_start: ~ title: Cascading Consequences of Heavy Rainfall for Urban Systems uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/cascading-consequences-of-heavy-rainfall-for-urban-systems url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: 'Protecting vulnerable people and places from the impacts of climate change involves infrastructure design (for example, green space and highly reflective roofing), along with social and institutional change (such as designating cooling centers). Social equity is supported by widespread participation in adaptation decision-making by non-profit organizations, local businesses, vulnerable populations, school districts, city governments, utility providers, and others. Source: EPA.' chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2017-08-02T14:13:10 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/the-bee-branch-greenway.yaml identifier: the-bee-branch-greenway lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 7 report_identifier: nca4 source_citation: ~ submission_dt: 2018-11-30T15:28:03 time_end: ~ time_start: ~ title: Urban Adaptation Strategies and Stakeholders uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/the-bee-branch-greenway url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information - attributes: ~ caption: "In response to a history of flooding, Dubuque, Iowa, installed the Bee Branch Creek Greenway to control flooding and provide recreational space.{{< tbib '138' '99f11503-c2c3-4ec5-825c-c6ed59d28613' >}} Photo credit: City of Dubuque, Iowa." chapter_identifier: built-environment-urban-systems-and-cities create_dt: 2018-04-03T20:10:20 href: https://data.globalchange.gov/report/nca4/chapter/built-environment-urban-systems-and-cities/figure/green-infrastructure-photo.yaml identifier: green-infrastructure-photo lat_max: ~ lat_min: ~ lon_max: ~ lon_min: ~ ordinal: 8 report_identifier: nca4 source_citation: ~ submission_dt: 2018-11-30T15:28:05 time_end: ~ time_start: ~ title: 'Greenway in Dubuque, Iowa' uri: /report/nca4/chapter/built-environment-urban-systems-and-cities/figure/green-infrastructure-photo url: ~ usage_limits: Figure may be copyright protected and permission may be required. Contact original figure source for information