Climate Threats to Tall Buildings: A Call to Action—and a Tool—for Owners and Developers

Lately, there’s been a lot of talk about sea-level rise, instigated largely by a study published last month in Nature Communications, which reported a “substantial and widespread” increase in ice shelf losses. The challenges stemming from fluctuating water levels along our coastlines demand urgent attention from everyone, but the owners and developers of tall buildings in particular should pay heed. These predicaments, arising from adverse weather events, thermal expansion, and other factors, are compounded by the escalating frequency of flash floods, rising tides, and cyclone surges. A significant number of coastal tall buildings face imminent threats, including some as far as 100 kilometers away from the oceanfront. Looking ahead, the impending rise in sea levels portends a greater impact on tall buildings—the majority of which are concentrated in coastal cities.

The challenges stemming from fluctuating water levels along our coastlines demand urgent attention from everyone, but the owners and developers of tall buildings in particular should pay heed.

Eighty-seven percent of the world's 2,005 buildings that are 200 meters (656 feet) or greater in height have been erected since 2000. Along with 40 percent of the world’s population, 70 percent of these tall buildings lie within 100 kilometers of a coastline. The unprecedented surge in tall building construction has coincided with a global mean sea-level rise of 84 millimeters (3.3 inches) from 2000 to the present, with projections indicating an increase to 119 millimeters (4.7 inches) over the next decade alone (see Figure 1).

When evaluating climate threats, a building's proximity to the coastline and its elevation from sea level must be considered, especially when the building's level of risk may be compounded by meteorological and seismological events that introduce flooding and instability. Considering these factors, a building’s elevation profile above mean sea level, in context with surrounding communities, can help us visualize the most critically threatened parts of our built environment.  

In a comprehensive analysis, CTBUH evaluated 23,156 tall buildings within 100 kilometers of a coastline, including completed, under-construction, and proposed structures, in six key global case study cities. Alarmingly, 33 percent of the buildings studied lie at 10 meters or less above the mean sea level in 2000. The National Oceanic and Atmospheric Administration (NOAA)'s projection of up to 2.2 meters of sea level rise by 2100 places 9 percent of the studied buildings, or 2,145 structures, in the most threatened coastal areas. On a broader scale, the study included an additional 2,996,473 non-tall buildings, of which 76,409, or 2.5 percent, sit at or below that critical point of 2.2 meters above sea level.

Alarmingly, 33 percent of the buildings studied lie at 10 meters or less above the mean sea level in 2000.

The interactive evaluative tool that CTBUH created to conduct this study provides unprecedented insight into the impacts of sea-level rise, with site-level specificity not available elsewhere (see Figure 2). To those with vested interests in tall buildings and their environs, this invaluable data can help future-proof existing infrastructure and inform crucial site selection decisions for proposed projects. At a scale as small as one square meter, case study cities can be explored building-for-building, with interactive data and a mean elevation profile available for the millions of buildings studied. 

Although our current stock of tall buildings is disproportionately threatened by sea-level rise, the near-exponential acceleration of tall building construction offers building owners and developers an opportunity to effect a paradigm shift in site selection, using data-driven approaches, such as the methodology employed in this study, to plan more comprehensively.

As we brace for the volatility of 21st-century climate change, adapting for a resilient urban future requires a proactive stance, grounded in and informed by a foundation of predictive data, that can help protect some of our cities’ most iconic and valuable assets.