Surging Seas Sea level rise analysis by Climate Central

Frequently Asked Questions

Who is Climate Central?  
What does Climate Central do?
Who funded Climate Central to develop the Surging Seas suite of tools?
What sea level and coastal flood tools and analysis does Climate Central provide?
How does Surging Seas differ from other sea level rise and coastal flood web tools available throughout the United States?
What research is Surging Seas based on?
What are intended audiences and uses?
How are affected areas determined on the map?
How does Surging Seas handle levees or natural ridges and what could be protected by them?
What are the elevation and levee source data and methods used for Louisiana? 
Where do Risk Finder data come from?
How does Surging Seas make local sea level rise projections?
Do projections account for local land subsidence?
How does Surging Seas make local flood risk projections?
How wide an area do projections apply to?
Do flood risk projections account for projected effects of climate change on coastal storm frequency or intensity?

 


Who is Climate Central?

  • Climate Central is a non-profit research and journalism organization providing authoritative, science-based information to help the public and policymakers make sound decisions about climate and energy.
     

What does Climate Central do?

  • Climate Central surveys and conducts scientific research on climate change and informs the public of key findings. Our scientists publish and our journalists report on climate science, energy, sea level rise, wildfires, drought, and related topics. Climate Central is not an advocacy organization. We do not lobby, and we do not support any specific legislation, policy or bill. Climate Central is a qualified 501(c)3 tax-exempt organization.
     

Who funded Climate Central to develop the Surging Seas suite of tools?

  • Surging Seas has been supported mainly by private foundations; see our list of supporters here.
     

What sea level and coastal flood tools and analysis does Climate Central provide?

  • Surging Seas Mapping Choices is an interactive global online map that allows anyone to search for a location and visually compare the local potential consequences of different emissions and warming scenarios. Users can view the long-term sea levels different pathways could lock in and embed the map or download map images. Learn more.

  • Surging Seas Risk Zone Map is a coastal flooding and sea level rise interactive map utilizing NOAA and NASA elevation data that provides the ability to explore inundation ​risk ​up to 30 meters (100 feet) above high tide lines across the world's coastlines, as well as local sea level rise projections at over 1,000 tide gauges on 6 continents. Users can search by city or postal code and embed the map or download images. Learn more.

  • Surging Seas Risk Finder provides localized sea level and flood risk projections, analysis of over 100 demographic, economic, infrastructure and environmental variables, community comparisons, and downloadable data and local reports about coastal flood and sea level threats to people, property and infrastructure. Available for U.S. cities, counties, states, zip codes, and much more. Learn more.
     

How does Surging Seas differ from other sea level rise and coastal flood web tools available throughout the United States?

  • View the Tools Comparison Matrix for an expandable chart that compares the functions and methods of different sea level rise and coastal flood web tools, including Surging Seas (Risk Zone Map and Risk Finder considered together). Choose your state from the drop-down menu.
     

What research is Surging Seas based on?
What are intended audiences and uses?

  • For Mapping Choices: Global citizens and leaders interested in understanding, comparing and communicating how different carbon pathways today will change the long-term map of the world.

  • For Risk Zone Map: Anyone interested in seeing or sharing local maps of sea level and coastal flood threats, and timelines of projected local sea level rise, globally. Maps provide screening-level assessments only; on-the-ground surveys are most accurate for site-specific decisions.

  • For Risk Finder: U.S. decision makers, planners, coastal managers, emergency managers, federal and state and municipal agencies, journalists and members of the general public interested in deeper analysis of coastal threats aggravated by sea level rise, including detailed local flood risk projections and exposure assessments matched to administrative, legislative and planning areas. Risk Finder data have been downloaded hundreds of times by government personnel, NGOs, companies, academics and reporters for stated purposes of planning, vulnerability assessment, research and reporting.
     

How are affected areas determined on the map?

  • Mapping Choices uses a threshold-based approach, comparing projected local water level surfaces to land elevation -- screening out only low-lying areas separated from the ocean by high ridges (see Methods section of the report for more detail). Risk Zone Map uses a “bathtub model” which additionally models hydrologic connectivity.

  • Both maps show water levels relative to local high tide lines (Mean Higher High Water) as opposed to mean sea level. Both maps are based almost entirely on high quality lidar elevation data, courtesy of NOAA, inside the U.S., and on satellite-derived data, courtesy of NASA, outside the U.S. For more information, click the information “i” icon on the top of the Risk Zone Map, or for information exclusive to U.S. areas view the appendices of our state reports.
     

How does Surging Seas handle levees or natural ridges and what could be protected by them?

  • Mapping Choices does not explicitly incorporate any levee data, as the time frame considered is long enough that the built environment is likely to change significantly before the water levels shown arrive.

  • Within the U.S., the Risk Zone Map does include levees mapped in major databases, and assumes they are sound and sufficiently high to prevent flooding at any water level. Outside the U.S., levees are not explicitly included. However, low-lying land separated from the ocean by an at-least 10-meter (30-foot) high ridge is not colored blue on the map, and is excluded from related analyses. For more information, click the information “i” icon on the top of the Risk Zone Map and scroll to the “Flood control structures” heading.

  • Risk Finder provides a variety of ways to view exposure analysis either accounting for or ignoring potential sea level and flood protection from levees and ridges.
     

What are the elevation and levee source data and methods used for Louisiana?

  • Some extra and updated sources are used for Louisiana due to its great complexity and large extent of low-lying land. For details, view our LA levees and elevation methods PDF.
     

Where do Risk Finder data come from?

  • We identified and collected over 100 demographic, economic, infrastructure and environmental variables using data drawn mainly from federal sources, including NOAA, USGS, FEMA, DOT, DOE, DOI, EPA, FCC and the Census. In its current form, the web tool does not contain many state or local datasets. If you are interested in having a state or local dataset included in the web tool, see our custom analysis page.
     

How does Surging Seas make local sea level rise projections?
Do projections account for local land subsidence?

  • Yes, projections account for local land subsidence or uplift, and other local factors as well.
     

How does Surging Seas make local flood risk projections?

  • Flood risk forecasts combine local sea level rise projections with assessment of annual flood risks based on historic flood statistics from select NOAA water level stations in the U.S. with at least 30 years of hourly data. Methods are based on peer-reviewed science, described here and on linked pages.
     

How wide an area do projections apply to?

  • Projections are based on specific tide gauge sites. They may or may not be indicative of nearby area risks. Local sea level rise projections are generally similar across neighboring areas. Flood risks can more easily vary across short distances, due to details of local topography and bathymetry and typical storm paths. Risk Finder includes a Location tab to allow comparison of results across multiple regional water level stations, to check for general consistency or differences.
     

Do flood risk projections account for projected effects of climate change on coastal storm frequency or intensity?

  • No. Flood risk projections assume that the storms of the future will statistically resemble the storms of the past. Some research suggests that intense storms and surge will become more common in places, possibly rendering the flood risk estimates here too low. However, projections of changes in storms are not yet well established across the U.S., and are geographically variable.