At the 41st UNESCO World Heritage Committee meeting recently held in Poland, delegates discussed the emerging issue of increased environmental threats to World Heritage sites. The proceedings concluded with a determination that urgent attention must be directed towards protecting United Nations Educational, Scientific and Cultural Organization (UNESCO) sites from the consequences of rising global temperatures. An integrated strategy is to be developed to identify actions necessary to protect and conserve the natural and cultural heritage value of these sites.
Around the globe there are a growing number of natural and cultural sites that have been afforded that status under the United Nations World Heritage programme. World Heritage status is awarded when assessments determine the sites as internationally important because of their cultural or natural significance. World Heritage status affords protections under international law. Some examples of cultural and natural World Heritage Sites are Stonehenge, Machu Picchu, Petra in Jordan, the Northwest Hawaiian Islands, the Lagoons of New Caledonia, Aldabra Atoll in the Seychelles and the Giant’s Causeway in Northern Ireland.
Australian World Heritage Sites include The Great Barrier Reef, archaeological sites in Queensland and South Australia and Uluru. There are also many buildings erected in colonial times that have been included due to their importance in the development of the Australian culture and society. Examples of such sites include the Royal Exhibition Building in Melbourne, the Sydney Opera House and Australian Convict Sites in Tasmania, Norfolk Island and Fremantle. Those convict sites are of special significance as they meeting the criteria for Outstanding Universal Value as described in the UN World Heritage Convention.
Recent Future Directions International articles have discussed environmental threats emanating from rising temperatures and changing global climate patterns. These threats are wide-ranging. Already, Australia has experienced an increased incidence of drought, rising coastal water temperatures and an increased incidence of extreme weather events such as cyclones and floods. The challenges this presents notwithstanding, scientific research resources are being concentrated to identify options for the mitigation and prevention of threats.
Changes in temperatures, rainfall patterns and moisture levels cause stress and damage to old buildings to the point where they will deteriorate and become structurally unstable. Inadequate protection and maintenance may result in a need for major restoration or, in the worst case, demolishment. This threat exists for many of Australia’s historically and culturally important convict-era buildings. Governments allocate millions of dollars towards the upkeep and maintenance of Heritage buildings but resources do not fully account for the possible effects of climate change as many adverse impacts are still subject to further study.
Understanding the potential damage to World Heritage buildings and ancillary infrastructure is key to developing strategies to reduce risk and aid protection and conservation. Some threats have been researched. Increased solar intensity and levels of ultra violet light when combined with water and wind may cause increased weathering of limestone building materials. Shifts in patterns of freezing and thawing may lead to general masonry damage. Furthermore, coastal environments in Port Arthur, Norfolk Island and Fremantle will be under threat from elevated salt levels, causing oxidation to occur on materials made from metal. Heavy rain increases the threat of water ingress. Increased runoff from rain events could weaken foundations. Other threats, however, are less well understood and there may be some that are yet to be identified.
Individually, this incomplete catalogue of the possible damage resulting from changes in climate patterns may seem unremarkable but collectively it is significant. If Australia is to meet its international legal and ethical obligations to maintain World Heritage sites, both natural and cultural, consciousness of the threat must be raised and resources allocated accordingly.