Climate change is already affecting Australia’s heritage (ANU 2009, Australia ICOMOS 2011). Australia’s climate has warmed significantly, rainfall regimes have altered, and extreme fire and weather events are increasing in frequency and intensity (see ‘Climate’ in the Atmosphere report). Cultural heritage places are both directly and indirectly affected. Heritage managers will need to identify and better integrate climate change and extreme weather risk into forward planning and preparation, allocate resources accordingly, and seek out opportunities to respond to the symptoms or pressures that arise from climate change (Australian Government 2015c). In particular, opportunities should be embraced to facilitate appropriate adaptation and increase resilience (Dunlop et al. 2012).
Climate change
Heritage (2016)
Climate change
Rising temperatures
Australia is warming, with temperatures having increased by 1 °C during the past 100 years (BoM & CSIRO 2016; also see the Atmosphere report), and 2013 was Australia’s warmest year on record. Rising temperatures alter ecosystems and may decrease resilience, with potentially devastating effects for niche-adapted rare and endangered species. Other pressures associated with climate change include the arrival or range expansion of other native species or introduced species, and increase in fire frequency and intensity. Climate change is also affecting seasonal patterns, such as plant flowering and pollen distribution. Rising temperatures particularly affect the marine environment, causing adverse impacts such as coral bleaching.
Warmer air temperatures cause deterioration of building fabric, and changes to lifestyles and cultural practices. More frequent extreme temperature events may lead to increased human pressure on heritage places, including the negative effect of abandonment.
Changing rainfall
Australia’s rainfall patterns have varied greatly during the past century, but there is a long-term trend of declining rainfall in autumn and winter in south-eastern and south-western Australia. Higher rainfall in northern Australia may result in flooding and erosion of heritage places and archaeological sites, and possible destabilisation of historic buildings. Changing rainfall regimes can alter groundwater recharge patterns, and impact on avenues of trees (including memorial avenues of honour) and historic gardens. Lower rainfall in southern Australia is affecting vegetation communities, leading to associated impacts such as habitat loss, increases in invasive species, more frequent and more intense fires, and destabilisation of structures and archaeological sites. Reduced rainfall may also reduce the economic viability of rural communities, or affect Indigenous sites that are water reliant or related to the ability of local communities to live on Country. There is also increasing recognition of the social, cultural and spiritual value of water to many Indigenous Australians, and the importance of recognising the needs of Indigenous communities in relation to water access and management (Australian Government 2015b; see Box HER7).
Box HER7 Macquarie River and the Macquarie Marshes—supporting cultural values through water management
The cultural values of some places important to Indigenous people may be dependent on water. The internationally significant Macquarie Marshes are the traditional homelands of the Ngiyampaa–Wayilwan people. Explorer Charles Sturt observed them camping along the Macquarie River and using elaborate fish traps in 1833. In May 2016, the Kevin McLeod Reconciliation Award from the Australian Government Department of the Environment and Energy made it possible for Ngiyampaa–Wayilwan elders to undertake a journey along the Macquarie River and into the marshes with environmental water and natural resource managers from the Australian and New South Wales governments.
Although they no longer live in the marshes, Uncle Tom Carney and Great-Aunty Shirley Stroud happily talked about their connection with important cattle and sheep stations, such as Oxley and Buckiinguy. A large eroded area on the floodplain, possibly an important gathering place, showed evidence of traditional stone toolmaking and ovens. Elsewhere, scarred coolamon and canoe trees sheltered saltbush and warrigal greens—traditional bush foods. These vital and knowledgeable elders enjoyed spending time on Country, but they were saddened by the degraded state of this culturally important river and floodplain landscape, and expressed concern about its future.
Mixed marsh–redgum forest wetland in the North Marsh Nature Reserve, Macquarie Marshes, after recent rain. The wetland supports habitat for nesting wedge-tailed eagles and other bird life, frogs and traditional cultural plants, such as nardoo and reeds
Australian Government and New South Wales environmental water allocations help to support river and wetland health in the Macquarie catchment, particularly during dry times. In 2012, wetter conditions across the catchment resulted in environmental water being released into the marshes during spring. Culturally significant reed beds in the North Marsh Nature Reserve were inundated as part of this flow. Following the flow, 140 Aboriginal women from across New South Wales gathered for a week to collect reeds and share their knowledge and skills of traditional basket weaving at the culture camp. This demonstrates the multiple benefits of environmental water, including the maintenance of cultural values and practices of Aboriginal people.
As the 2016 Macquarie River journey drew to a close, discussions focused on how, by working together, stakeholders can contribute to linking environmental water with cultural values and activities—to maintain a ‘living culture’ and to provide a way for stories ‘from way back’ to be told to the young people, so they can be involved in environmental water planning and ensure that Country is looked after for those to come.
Source: Louise Armstrong, Senior Policy Officer Ecological Communities, Australian Government Department of the Environment and Energy
Ruby salt bush (Enchylaena tormentosa) berries (a good source of vitamin C) found with warrigal greens under a large, water-stressed coolibah (Eucalyptus coolabah), which forms part of the threatened ecological community coolibah–black box woodlands of the Darling Riverine Plains and the Brigalow Belt South Bioregions.
Rising sea levels
Sea level is rising globally, and the intensity and frequency of extreme sea levels have increased on the east and west coasts of Australia. Australian sea level has risen more rapidly than the global average since 1993, a result of natural climate variability (see the Coasts report for further details). Rising sea levels will place major pressure on Australia’s coastal and island heritage, not only on natural heritage places, but also on cultural sites such as Aboriginal middens, sea cave deposits, archaeological sites and cave art sites. Places such as the Australian Antarctic Territory and the Torres Strait Islands are particularly vulnerable to rising sea levels. Indirect pressures will arise from changes to settlement patterns. Changes to hydrology, soil migration and damage from storm washes may also affect historic sites, such as Port Arthur or the Sydney Opera House.
Altered fire regimes
Fire presents a major threat to reserved lands and their ecosystems, and to Indigenous and historic heritage places (see Box HER8). The pressures and impacts from fire depend on a combination of management regimes and the responses of different plant groups. The nature, intensity, frequency and timing of fires are changing, as are the favourable ‘weather windows’ that allow proactive prevention measures.
Fire management regimes and response procedures have necessarily become more sophisticated and better adapted to the complex issues involved. Although focus understandably remains on protecting people and property, natural and cultural heritage values are increasingly recognised. If well conceived and implemented, wildfire abatement programs may reduce pressure on biodiversity, and Indigenous and historic values. There have also been positive environmental outcomes from active fire management, including emissions reductions (through early dry-season burning), and Indigenous knowledge being cultivated and transferred (through savanna fire management programs). In contrast, inappropriate fire management regimes may pose direct threats or affect cultural values.
Box HER8 Tasmanian Wilderness World Heritage Area fires in 2016
Extensive bushfires in Tasmania in early 2016 affected parts of the Tasmanian Wilderness World Heritage Area and the Western Tasmania Aboriginal Cultural Landscape, which is on the National Heritage List, as well as the Arthur–Pieman Conservation Area and Sundown Point State Reserve. These fires occurred after one of the driest summers on record and are likely to have been ignited by lightning strikes on peat soils.
Tasmanian alpine flora is not resilient to infrequent, large fires. Bare ground remains for half a century or more after fire, only decreasing once mammalian herbivores are excluded (Kirkpatrick & Bridle 2013). Many centuries may be required for coniferous heath to recover to a pre-burned state, even though most species apparently survive. In Tasmania, alpine vegetation is dominated by plants that have lasted since the Cretaceous period, but these relics have not developed long-distance dispersal mechanisms, which makes this community very vulnerable to changing fire frequency. Fires caused by increased ignitions from lightning and arsonists are a major conservation issue (Kirkpatrick et al. 2010).
The Tasmanian Parks and Wildlife Service, Forestry Tasmania and the Tasmanian Fire Service have responded to this challenge by developing an integrated fire management and firefighting system. The distribution of fire-sensitive vegetation is mapped, so that expert fire planners can direct firefighting crews to the places where they can best minimise the chances of further vegetation loss. In the wake of the 2016 fires, the opportunity is also being taken to survey and document Aboriginal heritage during the narrow window available to assess the post-fire archaeological landscape of the west coast of Tasmania, before regrowth of vegetation cover reduces ground visibility or coastal erosion affects Aboriginal values (Tasmanian PWS 2016a).
Cushion plant and pencil pine after the Mackenzie fire, Tasmanian Wilderness World Heritage Area
More frequent extreme weather events
Climate change is expected to increase the frequency and intensity of climatic events such as extreme rainfall, major sea level changes, severe fire weather, and droughts and floods, causing direct damage to natural and cultural heritage places. For example, respondents to the National Heritage survey (WHAM 2017) reported that more frequent and extreme weather events are the most significant climate change pressure threatening the listed values of National Heritage places (see Box HER9). Damage can also result from rescue and clean-up activities. Some places may suffer further deterioration through loss of economic viability.
Box HER9 Port Arthur Penitentiary—extreme weather impact on historic sites
Climate change is already posing risks for Australia’s World Heritage properties, including historic sites. The Port Arthur Historic Site is one of the 11 historic places that together form the Australian Convict Sites World Heritage Property, which was inscribed on the World Heritage List in 2010.
At Port Arthur, high tides and storm surges threaten historic assets. In 2011, a major storm occurred concurrently with a high tide, flooding the Port Arthur Penitentiary. The impact of debris damaged the building, and salt water soaked into the fragile brick and sandstone walls.
Originally constructed as a flour mill and granary, the penitentiary was converted in 1857 to house more than 480 convicts in dormitory accommodation and separate apartments. At the time of construction, it was the largest building in Tasmania, and remains a potent symbol of Australia’s penal origins.
The 2011 storm triggered a reassessment of the structural integrity of the penitentiary and confirmed the requirement for a major stabilisation project. Commencing in early 2014, the project was funded by the Tasmanian and Australian governments, and the Port Arthur Historic Site Management Authority, using revenue raised from heritage tourism.
This substantial conservation project included the installation of reinforced concrete ground beams supporting 14 huge steel columns; around 5 kilometres of stainless steel reinforcing rod; 91 high-tensile stainless steel grouted structural anchors, precision drilled vertically down through the walls; and stainless steel bracing plates, which are concealed beneath the sandstone cornice.
The project addresses the potential impact of future storm surges and will ensure the long-term conservation of the structure. It also provides the opportunity to interpret the building in new and exciting ways that will enhance the visitor experience.
The penitentiary project illustrates the need for heritage managers to adapt to new risks, and to monitor and manage the impacts of those risks. It is important that skilled staff and systems are in place to protect the fabric and values of the site by minimising damage when extreme events occur.
Severe weather and high tides at Port Arthur, 2011
Ocean acidification
Increasing ocean acidification has been formally identified for more than 15 years (Kleypas et al. 1999). Ocean acidification arises from the effect of carbon dioxide on the chemistry of the ocean (see the Marine environment report for further details). Around 30 per cent of the carbon dioxide released to the atmosphere from burning fossil fuels is absorbed by the ocean. Once carbon dioxide has entered the ocean, it reacts with water to create a dilute acid. Since before the Industrial Revolution, the acidity of the ocean has increased by 30 per cent and carbonate ion concentrations have decreased by 30 per cent. Calcium carbonate is the critical mineral that many animals (such as coral) secrete to form their skeletons and shells.
The Intergovernmental Panel on Climate Change has concluded that current rates of ocean acidification are the highest in the past 65 million years (IPCC 2014). Given that it will take more than 10,000 years to restore ocean chemistry (Hoegh-Guldberg et al. 2007), these changes are extremely serious. Ocean acidification is anticipated to lead to changes in ecosystems that will magnify substantially, with major consequences for people and ecosystems in coastal Australia. Ocean acidification presents a substantial risk to marine organisms and ecosystems such as the Great Barrier Reef (see Box HER24). The main impact is to reduce the ability of organisms such as corals to build and maintain structures, leading to wholesale dissolution and break-up, which in turn has serious implications for coastal regions that will be experiencing more intense storms and sea level rise (Professor Ove Hoegh-Guldburg, University of Queensland, pers. comm., March 2016).
Mackay R (2016). Heritage: Climate change. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/heritage/topic/2016/climate-change, DOI 10.4226/94/58b658bbe13a0
Professor Richard Mackay AM
