The Underwater is a community-led climate action project initiated by Xavier Cortada to raise awareness about sea level rise. It uses interactive public art installations to reveal South Florida’s elevation, spark conversations, and spur civic engagement. Since launching “The Underwater” in 2018, Cortada has enlisted thousands of residents and students to look up their home’s elevation and make yard signs.
Site-specific elevation yard signs, sustainable concrete sculptures, and murals announce a given location’s elevation above sea level, however, that meaning is unknown to anyone not familiar with the project. Due to the ambiguous nature of the numbers, coupled with their inherent strangeness, the elevation markers work to pique the interest of passersby. It is in these moments of intrigue that curious individuals can learn about the local impacts of sea level rise by scanning the embedded QR codes. In this way, the artwork allows people to discover their neighborhood’s elevation above sea level, explore relevant online resources, and learn how they can get involved in local climate action.
This methodology for engagement, education, and participatory art provides scientific facts to people in a way that is disarming. Rather than presenting people with data, graphs, and charts, this process can engage them in conversations and art-making that will simultaneously allow for listening opportunities and a memorable learning experience. Collaboratively mapping the topography of their community, neighbors reveal an alarming reality: declining property values, increased flood insurance costs, failing septic tanks, compromised infrastructure, climate gentrification, and collapsing ecosystems. Making the ‘invisible visible’ also challenges preconceived notions; living farther away from the coastline does not always correspond with lessened vulnerability to sea level rise.
This exhibition is organized by Cultural Programs of the National Academy of Sciences.
‘Underwater HOA’ Elevation Yard Signs
Elevation Yard Signs are markers that display a home’s elevation above sea level in an effort to catalyze conversation and action around the climate crisis. Distinct from traditional political or “for sale” signs, the ambiguous elevation numbers pique the curiosity of neighbors, friends, and family. Each sign also features Xavier Cortada’s Antarctic Ice Paintings, conceptually bringing Antarctica’s melting ice to the doorsteps of coastal residents as a stark warning of what will come without a rapid transition away from fossil fuels.
‘Underwater HOA’ DIY Elevation Yard Sign
Participants in the original “Underwater Homeowners Association” either installed yard signs with pre-printed numbers, or they would repurpose political yard signs by painting them over in white, drawing their elevation, and adding a final blue wave at the bottom to represent the rising seas. By encouraging people to transform old, often polarizing campaign signs, Cortada aimed to transcend political divides and foster a sense of unity, effectively turning symbols of contention into beacons of shared commitment.
Original drawings
In developing his Underwater HOA project, Cortada created stylized numbers to map the elevation of a community above sea-level, and help people understand how climate change impacts them personally. The black and white numbers seek to call attention to the measurable data that can be quantified in a world of misinformation and ideological divides. Using his gestural drawing, the bold, organic numbers were created to bring a personal and welcoming element to the conversation of climate change. The swirls and expressive markings could also be seen as the varied pathways on the journey to building a home and family. These elements come together to form a number that measures the vulnerability of the very structure where those life processes form.
Underwater HOA: Elevation Drive
Cortada recruited art students from four local high schools to help him paint Elevation Drive at four major intersections along a 2.5-mile stretch of Killian Drive (the Village of Pinecrest, Florida’s main thoroughfare). As the residents of Pinecrest would drive along the road from east to west, traveling inland and away from the Atlantic Ocean, most would expect to gradually move to higher ground that is less vulnerable to rising seas. Many were surprised to find, however, that intersections further west had lower numbers than some closer to the coast. This discovery revealed that Pinecrest is located on a ridge and that those living west of the ridge were actually more vulnerable to sea level rise than some of their neighbors closer to the bay.
Underwater Elevation Sculptures
Xavier Cortada is creating a permanent interactive art installation of sustainable concrete elevation sculptures across all of Miami-Dade County, Florida’s 250+ parks. Anyone who scans the sculptures’ QR codes can discover their own home’s elevation above sea level and pick up a free Elevation Yard Sign to put in their front yard, thereby joining the county-wide installation and raising awareness in their neighborhood.
The Cortada Foundation is activating the site-specific sculptures by hosting educational programming and ceremonial performances. At each dedication event, the artist leads participants, one at a time, in pouring seawater from Biscayne Bay over the sculpture. In this ritualistic process, everyone commits to do what they can so that moment will be the last time saltwater makes contact there.
Designed to stand the test of time, these art pieces will outlive their own accuracy, their numbers staying fixed while the elevation of their locations gradually declines. The sculptures also aim to generate exposure for sustainable concrete as a climate solution, helping the cement and concrete industry accelerate its decarbonization.
Underwater Elevation Sculpture (Hard Positive Numbers)
These numbers are used in the process of creating the large sculptures, each depicting a park’s elevation above sea level. These concrete markers are made from seawater, recycled aggregate and non-metallic reinforcement, aiming to feature building materials that are less energy intensive and better for the environment.
Underwater Elevation Sculpture (Silicone Mold)
Using his original Elevation Yard Sign designs, Cortada created clay sculptures that were later turned into silicone molds. These molds are then repeatedly employed in the process of making dozens of sustainable concrete replicas for park sculptures across Miami-Dade County.
Underwater Gulf
BRADENTON, FL
MOBILE, AL
BILOXI, MS
NEW ORLEANS, LA
During the summer of 2022, Xavier Cortada mapped the Gulf Coast by placing elevation markers at city halls in four coastal states – Florida, Alabama, Mississippi, and Louisiana – depicting their elevations above sea level. By doing this at the very place where city officials make decisions about municipal budgets, as well as land use, planning and zoning, Cortada made visible the threat that sea level rise poses to each city’s future tax base.
‘The Underwater’ Elevation Yard Sign (Front & Back)
The initiative’s latest iteration, The Underwater, encourages people to paint or draw their elevation on top of an Antarctic Ice Painting backdrop. Their elevation then sits alongside a QR code that invites others to find their own elevation. The back of the sign prominently features Cortada’s ‘6’ drawing, chosen because the accompanying QR code reveals a projection of what 6 feet of sea level rise would look like in Broward and Miami-Dade Counties.
Underwater Broward: In 2024, Cortada brought “The Underwater” project to 10 Broward County schools.