Barrier Reef

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GUEST OBSERVER
Rising sea levels are widely recognised as a threat to coastal communities worldwide. In Australia, the Climate Council estimates that at least A$226 billion of assets and infrastructure will be exposed to inundation if sea levels rise by 1.1 metres. Another report recommended that global mean sea level rise of up to 2.7 metres this century should be considered in planning processes.
The Queensland state government has commissioned the QCoast2100 program. This program aims to help with the development of coastal climate adaptation plans for Queensland communities exposed to sea-level rise. 
Although the largest population centres in Queensland are in the state’s southeast, several of the most populous regional centres in Australia are located along the Great Barrier Reef coastline between Gladstone and Cape York. These include Townsville, Cairns, Gladstone, Mackay and Port Douglas.
A major task in developing coastal adaptation plans under the QCoast2100 program is to model inundation from a range of scenarios for sea-level rises and assess how assets will be inundated in the future. However, another threat is on the horizon.
How urban centres are protected
Urban centres along the reef’s coastline, which forms the majority of the Queensland coast, are protected from major ocean storms by natural deposits of coastal sediments. These include dunes and associated vegetation such as coastal forests, wetlands and mangrove systems. 
These natural features continue to exist largely because the Great Barrier Reef’s outer reefs dampen incoming ocean waves. Although exposed to the occasional cyclone – which can lead to short-term erosion at specific locations – much of the coastal zone inside the reef is slowly growing out into the sea. 
This increasing buffer zone can form a natural barrier to coastal recession.
A recently released report estimated the total economic, social and icon asset value of the Great Barrier Reef at A$56 billion. By design, this report did not include many of the ecosystem services the reef provides. One of these is its role in reducing the energy of waves that impact the coastline behind the reef.
However, an earlier assessment of the total economic value of ecosystem services delivered by the reef estimated the present coastal protection benefit is worth at least A$10 billion. 
Despite the inherent uncertainties in such assessments, it is clear the reef acts to reduce incoming wave energy and its impacts on cities and towns along much of the Queensland coastline. The total economic value of these benefits is in the billions of dollars.
What role is bleaching playing?
The Great Barrier Reef’s ability to keep protecting the Queensland shoreline, and communities living along it, depends upon the ability of individual reefs in the system to grow vertically to “keep up” with rising sea level.
The jury is still out on whether the outer reefs will be able to keep up with predicted rises. This is an active area of research.
However, it is clear reefs that are extensively affected by coral bleaching will struggle to maintain the essential processes required for productive reef-building. Many reefs are now experiencing net erosion. 
Predictions of ocean warming suggest that bleaching events will become even more common in coming decades. Increasing levels of atmospheric carbon dioxide are also making the oceans more acidic, which makes it more difficult for organisms such as corals to maintain their skeletons, which are made of calcium carbonate. This mineral dissolves more rapidly with increasing acidification, reducing the reef’s capacity to recover from storm damage and coral bleaching.
Therefore, as bleaching events and acidification continue, the outer reefs that protect the Queensland coast from ocean waves will increasingly struggle to perform this function. 
In turn, over time the Queensland coast will potentially suffer from more coastal erosion, which may increase the vulnerability of coastal infrastructure. This effect, combined with rising sea levels leading to more coastal inundation events, multiples the risks to coastal settlements and infrastructure.
<a href="https://theconversation.com/profiles/mark-gibbs-199704" target="_blank">Mark Gibbs</a> is Director, Knowledge to Innovation; Chair, Green Cross Australia, Queensland University of Technology and author for <a href="https://theconversation.com/au" target="_blank">The Conversation</a>.
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As a coastal defence, the Great Barrier Reef’s value to communities goes way beyond tourism

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GUEST OBSERVER
The most recent report card on the Great Barrier Reef’s water quality highlighted major changes that need to be made to meet targets by 2018. 
Sediment and pollutant runoff from land use have increased 2-3 fold since 1850, largely driven by agricultural land clearing and grazing, while fertiliser used in sugar cane farming contributes to nitrogen runoff.
Runoff increases coral’s sensitivity to bleaching and disease, shifts the balance between coral and algae, leads to a build-up of pollutants in marine species that are long-lived or high in the food web, and increases the chances of crown-of-thorns starfish outbreaks.
Improving water quality will likely increase the health of reef organisms, and help reefs to bounce back from disturbances. 
Government investment plans need to account properly for the total estimated value of the Great Barrier Reef and past progress in reducing runoff. An estimated A$500 million per year is needed to improve management action. 
So what’s the best way to meet these targets? You won’t be surprised to find that scientists are working on the answer. But innovative projects fusing art and science are also appearing in north Queensland. 
<h2>The problem of collective action</h2>
Like many environmental issues, runoff on the Great Barrier Reef is a classic example of a collective action problem. Collective action is at the heart of this issue in two ways. 
First, the alongshore transport of sediment and runoff pollutants by currents means that the effects of managing runoff along one section of coastline may be felt elsewhere. The condition of the reef adjacent to a particular river mouth may not, therefore, necessarily reflect the land management within that river’s catchment. 
Second, the health of the reef is dependent on other factors, such as bleaching driven by increased sea surface temperatures related to climate change. These are caused by many geographically remote activities (for instance, someone burning coal in London). 
Collective action problems can be understood through US academic Garret Hardin’s famous “tragedy of the commons” theory. This theory states that self-interested individuals acting rationally may not behave in the best interests of the whole group.
Hardin used the example of a group of herdsmen allowing their cattle to graze a pasture that is running out of fodder. For an individual herdsman, the cost of removing cattle exceeds the benefit of leaving some pasture for the future, unless other herdsmen also agree to remove cattle.
Similarly, it takes an exceptional individual to reduce their runoff impacts, in light of the agricultural benefits to be gained from activities that increase runoff volume and decrease its quality (such as land clearing and use of fertilizers). This is particularly the case when others are not acting to abate their own activities. 
Many farmers say that the Reef 2050 target to reduce runoff by 80% by 2025 is not economically viable. But without acting now, our metaphorical common (the inshore Great Barrier Reef) will continue to degrade.
<h2>Best environmental practice</h2>
Agriculture is a social and cultural activity, just as much as it is a process of environmental engineering, and the push to transform farming practices needs to recognise this. Top down incentive schemes do have some impact, but could there be a better way?
For instance, for sugar cane growers, the Smartcane Best Management Practice (BMP) Guidelines are an attempt by the industry to shift farming practices towards compliance with government directives to reduce run-off impacts on the reef. 
The Smartcane BMP guidelines aim to improve farming practices through seven principles:
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Soil health and plant nutrition management 
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Pest, disease and weed management 
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Drainage and irrigation management 
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Crop production and harvest management
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Natural systems management
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Farm business management
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Workplace health and safety management
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As with many corporate social responsibility initiatives, growers who volunteer for Smartcane BMP are required to assess their current practices and set benchmarks for improvement in order to receive accreditation that indicates good environmental practice. There are clear marketing and, in many cases, cost-cutting benefits that motivate farmers to participate. 
This has driven some examples of good practice within the farming community. However, as the 2015 report card shows, “only 23% of sugarcane land was managed using best management practice systems”, which is inadequate for achieving the Reef 2050 goal of an 80% reduction in dissolved nitrogen loads from agricultural runoff by 2025. 
<h2>Motivating farmers</h2>
One project which engages with this problem is Sugar vs the Reef? by artists Lucas Ihlein, Kim Williams and Ian Milliss. This project is based on the idea that there is a greater chance of influencing farming practices if the desire to improve environmental performance comes from within the farming community. Innovation is celebrated from below by staging public collaborative events to generate dialogue about agriculture’s complex social and environmental interactions. 
For example, over the next two years, the project will coordinate a collaboration between Mackay Botanical Gardens, sugar cane farmers and community members to plant a dual crop of sunflowers and sugar caneas a highly visible work of “land art”.
This crop - whose cycle of planting, growth and harvesting will exceed the minimum standards of BMP - will stretch over four hectares near the centre of Mackay. Over two years, the project will engage sugarcane farmers, artists, high school students, members of the Australian South Sea Islander community, the Greater Whitsunday Food Network, soil and reef scientists, as well as the Great Barrier Reef Marine Park Authority.
While it is easy to point the finger at agricultural practices as a major cause of poor water quality in the inner waters of the Great Barrier Reef, change will be slow until the complex social factors that shape modern farming are recognised. This requires deeper engagement with the varied cultures of farming.
Sarah Hamylton is senior lecturer, School of Earth and Environmental Sciences, University of Wollongong and can be contacted <a href="https://theconversation.com/profiles/sarah-hamylton-134715" target="_blank">here</a>.
Lucas Ihlein is ARC DECRA research fellow, University of Wollongong and can be contacted <a href="https://theconversation.com/profiles/lucas-ihlein-112028" target="_blank">here</a>.
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