This map shows U.S. land less than 20 feet, or 6 meters, above the high tide line. That is the minimum amount of eventual sea level rise projected from 2 degrees Celsius (3.6°F) of global warming, according to a comprehensive review published in the journal Science.
2°C is an internationally agreed target for trying to limit warming.
The areas colored blue are the areas below 6 meters -- areas that would eventually be permanently underwater. When could the sea fully reach this height? Perhaps sooner than 200 years from now (see Table 1 in this scientific paper), or perhaps much longer (for example, see this paper). It is easier to estimate how much ice will eventually melt from a certain amount of warming, than how quickly it will melt, which involves more unknowns.
Carbon pollution casts a long shadow. When people burn fossil fuels or clear forests today, the extra carbon we put in the atmosphere stays long enough to add to global warming for thousands of years. Neither warming nor sea level rise will stop when we stop polluting.
For fuller discussion and data analysis, including what the consequences could be for American cities and global nations, explore the Related (+) menu above the map.
The methodology for building this sea level map comes from Climate Central’s peer-reviewed scientific research, updated with more accurate elevation data (laser-based lidar) and applied here to a new and higher sea level.
Credits and Sources
Climate Central’s sea level rise group conceived and led the research behind this project, and conceived the tool and its architecture. Stamen Design in San Francisco designed and built the map and mobile tool. The National Oceanic and Atmospheric Administration (NOAA) and U.S. Geological Survey (USGS) were data sources for elevation; NOAA was the sole source for tidal elevation. Graphical map tiles are by Stamen Design, under CC BY 3.0. Map data by OpenStreetMap, under CC BY SA.
Map development was supported by U.S. National Science Foundation grant ARC-1203415.