OBSERVER: Copernicus for the preservation of global cultural heritage sites

Thu, 30/06/2022 - 12:00

The European Union is one of the leading global actors supporting culture as a foundational aspect of nationhood, and thus actively supports and fosters national identities and collective memory in celebration and preservation of cultural diversity. Amongst the most important vehicles of memory for communities, societies and nations are cultural heritage sites. Cultural heritage is defined by UNESCO as a set of tangible and intangible artifacts, monuments, sites, museums that have “a diversity of values including symbolic, historic, artistic, aesthetic, ethnological and anthropological, scientific, or social significance.”

While a community’s cultural heritage can often act as a significant economic asset (most commonly as a tourist attraction), it also carries out a key role in the formation and evolution of national/social identity, acting as a cornerstone of belonging. The importance of cultural heritage sites and their vulnerability against natural and anthropogenic threats has long been recognised by both European institutions such as the European Commission and the Council of Europe, as well as by global actors such as UNESCO.

In 2015, a strategic partnership between UNESCO and the United Nations Institute for Training and Research (UNITAR) was established. Its aim is to contribute to the work of heritage experts with satellite images developed through UNITAR’s UNOSAT programme. Not only are images from Copernicus Sentinels supporting UNESCO-UNITAR in their evaluation and protection of cultural heritage, but information and forecasts from Copernicus thematic services are also used to ensure the preservation of sites.

Indeed, cultural (and natural) heritage is threatened by the severe adverse effects of climate change; heat waves, fires, rising sea levels, storm surges, flooding and other by-products of the climate crisis can cause significant damage to monuments and sites. The Copernicus Climate Change, Atmosphere, Marine and Land Monitoring services, can support the preservation of cultural heritage through data and information products and analysis tools.

Italy, as the country with the highest number (58) of UNESCO World Heritage Sites in the world , has been one of the most active supporters of the development of Copernicus services for the monitoring and protection of cultural heritage. After an initial workshop in 2017, a formal Italian request in 2018 provided the spark for the institution of the Copernicus Cultural Heritage Task Force, later formalised by the Copernicus Committee. The task force, coordinated and chaired by the Italian Ministry of Cultural Heritage, is composed primarily of national experts from EU member states, hailing from both the cultural heritage and the Earth Observation domains. On the task force’s list of agenda items was the need to define and adopt user requirement coordination mechanisms, in order to assess the existing synergies and gaps in the data and information provided by Copernicus in support of heritage monitoring. This has provided valuable insight, helping to define future development needs in order to expand the scope and impact of EO data for this specific domain.

While the benefits of remote sensing for cultural heritage monitoring have long been known, the full, free and open data access through which Copernicus publishes and disseminates its data and information has helped to increase the number of relevant applications in this domain. The high temporal and spatial resolution of the Sentinel satellites are valuable for short-term cultural heritage monitoring, while coupling Sentinel data with legacy space programmes (such as Landsat or ENVISAT) can reveal useful information on the long-term evolution of a heritage site and its surroundings.

There are several examples of products relevant to cultural heritage monitoring which greatly benefit or indeed rely upon EO data and information. To name a few, land use and land change data sets, ground motion detection, coastline erosion monitoring and urban sprawl monitoring all make extensive use of EO data. The same applies to air quality monitoring which helps to forecast potential episodes of acid rain, or marine monitoring and bathymetry when it comes to underwater cultural heritage sites. Finally, the Copernicus Security Service’s Support to EU External Action component can be used to monitor cultural heritage sites in remote areas affected by conflicts using Very High Resolution satellite imagery.

One simple but effective example of the value of EO data is provided in the image below.

Exhibit 1: Urban sprawl of the city of Cairo, from 1972 to 2022

The two images show the city of Cairo, Egypt, in 1972 (left, image from Landsat 1) and 2022 (right, Copernicus Sentinel 2). The white circle highlights the Pyramids of Giza. Note the impressive urban sprawl on both banks of the Nile; the Giza Necropolis has effectively been incorporated into the city. Credit: USGS and Copernicus

Moreover, disaster risk management for cultural heritage has been characterised by an analysis of the NAVIGATOR project, wherein six steps relevant to management of hazards within the specific domain of cultural heritage protection were identified and are reproduced below.

Exhibit 2: Disaster Risk Management Cycle for cultural heritage monitoring

*The Disaster Risk Management Cycle, adapted from Agapiou, Lysandrou & Hadijmitsis, 2020.*

Earth Observation products and services such as those developed and offered by the Copernicus component of the EU Space Programme are well-suited to contribute to several of the steps along the Disaster Risk Management Cycle. Remote sensing data and information can support knowledge of the environmental context (step 1), the identification of different potential threats resulting from either natural causes as well as manmade hazards (step 2), and the analysis and evaluation of specific risks to heritage sites derived from the previously identified dangers (steps 3 & 4). Indeed, the Risk & Recovery Mapping component of the Copernicus Emergency Management Service has recently been activated by Greece to develop multi-risk analyses for the Delphi and Ancient Olympia archaeological sites in Greece. This activation will produce hazard, exposure, vulnerability, and risk geo-data and maps for forest fires, flash floods, plain floods, earthquakes, landslides, soil erosion.

Furthermore, EO data is a valuable tool to inform the response and treatment of any potential damages (step 5), as well as being instrumental in periodically and frequently monitoring the site (step 6). Those final two steps benefit greatly from Copernicus’ Sentinel high revisits rates, providing timely, reliable and up-to-date data and information of the relevant area.

The new European Ground Motion Service (EGMS) from the Copernicus Land Monitoring Service, also provides information of high relevance for the monitoring of ground subsidence in and around cultural heritage sites.

Ground subsidence data, retrieved from Copernicus Sentinel-1 radar imagery, shows vertical movements of more than 20 cm in areas of the city of Venice. Credit: Copernicus Land Monitoring Service/EGMS (implemented by the European Environment Agency)

Rapid response tools shall be coupled with long term analyses and assessment of evolving climate-related risks. The Copernicus Climate Change Service (C3S) offers an invaluable source of data to support sites managers, local, regional and national administrations for the preservation of cultural and natural heritage sites. Long term climate indicators, trends and return probabilities can be computed for the most common natural hazards such as floods, fires, windstorm and landslides to define vulnerability rankings per site (see, for instance, the approach of the INTERREG project STRENCH).

Bar chart of yearly temperature anomalies 1980 – 2021 (reference period 1986 – 2005) for the protected site of Oasi Cesine, in Apulia, Italy, a Ramsar wetland site of international importance. Temperature increase is affecting the entire ecosystem. Credit: Copernicus Climate Change Service (elaboration by MEEO srl)

In conclusion, while cultural heritage is not one of the six primary thematic areas tackled by Copernicus services, it has increasingly become a key area of interest for both the European Union and global institutions. Copernicus’s free and open data policy has bolstered significantly the uptake of EO data for cultural heritage monitoring. Uptake will undoubtedly continue to grow, as an ever-increasing amount of data from remote sensing systems becomes available to global users.