The catastrophic partial collapse of a 13-story condominium along the coast of Miami is raising questions about coastal resiliency as speculation around the role of climate change in the incident grows.
Authorities are still working to identify causes of Thursday’s disaster, which all experts Motherboard spoke to agree are likely complex and multifaceted.
Videos by VICE
Shortly after one of the building’s wings fell to the ground on Thursday, researchers at Florida International University (FIU) resurfaced a 2020 report that highlighted the building, located at 8777 Collins Avenue in Surfside, Miami, as the site of localized land subsidence in the 1990s. In the immediate aftermath of the incident, the report was picked up by a number of national news outlets—in the days that followed, concern that the collapse was climate-related mounted on social media.
The study, which used data from 1992 to 1999 collected via satellites that orbit the earth and collect Interferometric Synthetic Aperture Radar (InSAR) measurements—readings of the movement of earth’s surface or objects atop it—located a pattern of land loss along the western edge of Miami, where a number of single-family homes were built on reclaimed wetlands (swampy areas that were cleared and turned into land for real estate development). It also located land subsidence—the process by which the earth’s surface sinks as soil compacts—in an area surrounding a condo near Miami Beach, that Dr. Shimon Wdowinski, professor in the department of earth and environment at FIU and co-author of the report, identified as the Champlain Towers South on Friday.
“Our study, which was based on observations from the 1990s, detected a cluster of very localized subsidence in that complex,” Wdowinski told Motherboard over the phone.
Land subsidence can occur in a number of ways, Wdowinski’s paper notes. Soil can compact naturally when groundwater is extracted from beneath the earth’s surface, when permafrost melts, or when oil and gas stores are mined, for example. By 2000, land subsidence had affected an estimated 17,000 square miles of the US; it’s one of the primary causes of land loss in southern Louisiana, which is losing around a football field of land every 100 minutes. Subsidence can occur naturally across the surface of the earth, but is more often caused by human interference, like groundwater pumping.
The building was sinking at a rate of 1 to 3 millimeters per year in the 1990s, the paper notes. More recent estimates that Dr. Manoochehr Shirzaei, associate professor of geophysics and remote sensing at Virginia Tech derived from InSAR data indicate that this pattern continued more recently near—but not directly under—the building.
According to Shirzaei, differences in subsidence rates between parcels of land pose the gravest threat to building integrity—rather than land subsidence as a whole, which has occurred across the state at various rates without causing destruction. He points to security camera footage of the tower’s fall captured from a neighboring building, which shows one side collapsing before another, as a sign that differences in land movement tore the building apart.
“Think about if you’re standing, each of your feet is on one block, and the two blocks move up or down together very slowly, you wouldn’t even realize that, right?” he explains. “Now, think about if the block that is under your left foot moves down faster. You immediately lose your balance and you fall. This is the process that we look for.”
Shizraei said that they believe climate change could have played a role in the collapse, although it’s not likely to be the sole cause.
“I think it’s a combination of all several factors,” he said, of the building collapse as a whole. “Engineering flaws come hand in hand with anthropogenically- and maybe naturally-driven land subsidence and sea level rise.”
Building engineers have identified structural damage starting in the garage as an early suspect, but authorities have warned against speculation. The search for victims is now in its sixth day, as the incident’s death toll climbed to 11 and 150 people remain unaccounted for. On Saturday, Miami-Dade County Mayor Daniella Levine Cava ordered the county to audit all buildings older than 40 years.
“We want to make sure that every building has completed their recertification process, and we want to move swiftly to remediate any issues that may have been identified in that process,” Cava said in a press conference Saturday. “We’re going to conduct this audit within the next 30 days, and we are beginning right now.”
The possible role of climate change in the tragedy was top of mind for many. Like many coastal communities in the U.S., Miami has long been considered highly vulnerable to the threat of climate change and rising tides. A 2020 report by nonprofit thinktank Resources for the Future called the city “one of the most at-risk cities in the world” to coastal flooding and storms, pointing to Miami Beach, specifically, as notably exposed to flooding and saltwater intrusion.
Dr. Timothy Dixon, professor in the school of geosciences at the University of South Florida, points to the latter as a possible factor in the condominium collapse. Salt tends to speed up the rusting of steel beams that hold up buildings, weakening it more quickly than it otherwise would (all building beams rust eventually, but salt, with two oppositely charged ions, are reactive with steel and iron, and move this process along quicker, Dixon says). As sea levels rise, building foundations become more vulnerable to saltwater exposure, and thus, to rapid wear and tear.
“That is a concern for any coastal city,” Dixon said. “It’s possible that, linked to climate change, the combination of the land going down and sea level coming up has caused saltwater intrusion, which contributed to corrosion of things below the land’s surface.”
Though Dixon, Wdowinski, and Shirzaei all remained firm that climate change-related factors cannot yet be singled out as the cause of the building collapse, the incident underscores the importance of coastal resilience plans more broadly. Though every coastal community experiences the man-made effects of climate change differently, storm surge, land erosion, flooding and water level increases imperil people and infrastructure, alike. An estimated 13-million Americans could face displacement from sea level rise by 2100, a 2016 report found. For many, the Miami collapse is a warning sign that those effects have already begun—for Shirzaei, it’s a sign that cities need to prepare.
“Every coastal community must think about one adaptation strategy that best fits them,” Shirzaei said. “That could be relocating the entire community, it could be building fences, sea walls, or it could be elevating lands or building better foundations.”
“It’s unavoidable,” he added. “And it’s coming, and it’s going to cause damage, collapse of buildings.”
Though the cause of the disaster in Miami is unlikely to be uncovered soon, and climate change may or may not have played a critical role, discussions around the role of the climate crisis in terrible events is sure to be something society deals with more frequently in the future.
