Emma Knezevic and Bill McCormick, Science,
Technology, Environment and Resources
Threats to the Great Barrier Reef from poor water quality and climate change urgently need to be addressed to maintain its natural values and ensure long term sustainable uses of the park.
The Great Barrier Reef (GBR) extends 2,300km along
the coast of Queensland (see Figure 1) and is the world’s largest system of
coral reefs. With great diversity of species and habitats, the GBR is one of
the richest and most complex natural ecosystems on earth. It was inscribed on the
World Heritage List in 1981. The
reef is visited by more than two million people each year and the catchment
a value-added economic contribution of $5.7 billion annually.
Managing and conserving the GBR and its unique
values is a challenge, and both the Australian and Queensland Governments have
The Great Barrier Reef Marine Park Authority
(GBRMPA), a Commonwealth authority, manages
the Great Barrier Reef Marine Park, as established by the Great Barrier Reef
Marine Park Act 1975 (Cth). GBRMPA’s regulatory tools include zoning, plans
of management, permits
The Queensland Government, through the Queensland
Parks and Wildlife Service and Fisheries Queensland, works with the
Commonwealth in managing adjacent state marine parks and islands.
Successive state and Commonwealth governments have
referred to the GBR as the ‘best
managed reef in the world’. They highlight GBRMPA’s multiple-use approach
fishing, tourism and recreation, as well as maritime and transport access.
Figure 1: Great Barrier Reef and adjacent
Reef Plan Report Card Summary
Threats to the GBR
Threats to reef health include coral bleaching due
to elevated sea temperatures, ocean
acidification, outbreaks of Crown of Thorns Starfish (COTS), and cyclones. Threats
also arise from coastal development, agriculture and industrial activities on adjacent
land and the associated catchment
run-off from these activities. As such, land and water management within or
adjacent to the GBR contributes to cumulative impacts on the
A 2012 study,
published by the National Academy of Sciences (NAS), found that coral cover had
declined by around 50% since 1985. Tropical cyclones, predation by COTS and
coral bleaching accounted for 48%, 42% and 10% of the estimated loss,
respectively. The authors concluded that tropical cyclones and coral bleaching
can be linked to climate
change and mitigation measures are unlikely to be effective in the short
Water quality and reef management
In 2003, the Queensland and Australian Governments
released the Reef Water
Quality Protection Plan (Reef Plan) to address the issues of run-off from
land. This plan was updated
in 2009 and 2013.
Funding to implement the plan was sourced from the
Natural Heritage Trust, Caring for our Country and Reef Rescue programs. The
Reef Plan website states
that, in 2013, the Australian and Queensland Governments collectively allocated
$375 million over five years to its implementation. In 2015 a further $100
million was committed by each government.
Outlook Report 2014, prepared by GBRMPA, explains that run-off into the GBR
from adjacent land carries increased nutrients found in fertilisers such as
nitrogen and phosphorus, as well as pesticides and herbicides used in
agriculture. Water quality is further reduced by sediments.
The impact of run-off is uneven across the GBR, and
depends on pollutants and their concentrations, catchment sources and distance
of reefs from the coast. Similarly, the effects of coral
bleaching and COTS
outbreaks vary by location and timing. The 2012 NAS study (above) reported
that the remote northern region had relatively low
mortality from COTS and cyclones, and coral cover was stable with the exception
of a slight decline due to bleaching from 1998 to 2003.
In contrast, a 2016 bleaching event has most severely impacted the northern
Crown-of-Thorns Starfish (COTS)
Occasional COTS outbreaks are considered natural,
but outbreak frequency and intensity have
increased as a result of reduced water quality. In particular, increased
nutrient levels as a result of catchment run-off encourage plankton blooms, increasing
the food available to COTS larvae. During COTS outbreaks, the starfish eat
coral faster than it can re-grow, leading to a decline in coral cover.
In addition to intensive efforts to manually
control COTS during outbreaks, improving the water quality is expected to reduce
the likelihood of COTS outbreaks.
bleaching is caused by heat stress when water temperatures rise for
prolonged periods. Coral bleaching is the term used when tiny marine algae that
live in coral (zooxanthellae) are expelled. The coral tissue then appears
transparent, revealing the white skeleton.
Significant coral bleaching outbreaks occurred on
the GBR in 1998 and 2002. However,
2016 has seen the most extensive bleaching event with reports of up to 90% of
some reefs affected to some degree. Impacts from this event are still
unfolding, but coral mortality (at June 2016) is 22% across the GBR,
with the most affected sites observed in the northern section. The Australian
Institute for Marine Science explains:
Between February and May, the GBR experienced
record warm sea surface temperatures. Extensive field surveys and aerial
surveys found bleaching was the most widespread and
severe in the Far Northern management area, between Cape York and
Port Douglas. Here, bleaching intensity was ‘Severe’ (more than 60% community
bleaching). Bleaching intensity decreased along a southerly gradient. While
most reefs exhibited some degree of bleaching, this bleaching varied in
intensity (from less than 10% to over 90% community bleaching) and was patchy
throughout most of the management area. (View the GBRMPA map for more information.)
World Heritage in danger?
Since 2005, the World Heritage Committee has
repeatedly warned Australia that the GBR was under consideration for inclusion
on the List of World Heritage In Danger.
‘In danger’ listings are designed to:
...inform the international community of
conditions which threaten the very characteristics for which a property was
inscribed on the World Heritage List, and to encourage corrective action.
The World Heritage Committee’s decisions relating to
the GBR in recent years have raised concerns about proposed and existing
developments in and near the World Heritage Area, water quality issues
(including sediment and agricultural nutrient run-off), and climate change.
The Australian and Queensland governments have responded
to these concerns in a number of ways, to ensure the GBR is not placed on the
‘in Danger’ list. A key part of this response is the Reef
2050 Long-Term Sustainability Plan, which was informed by a strategic
assessment of the impacts on the reef. This Plan aims to put in place a
long-term, comprehensive approach to improve the condition of the GBR. The Implementation
Strategy identifies priority actions in the implementation of the Reef 2050
Controversy arose in May 2016 when the Australian
Government’s Department of the Environment successfully requested the removal
of references to Australian sites, including the GBR, in a United Nations report,
Heritage and Tourism in a Changing Climate. The Department was reportedly
seeking to avoid confusion over terminology.
Proposed Reef Fund
The Coalition’s 2016 Election policy
proposes the creation of a $1 billion Reef Fund to finance clean energy projects
in the GBR catchment region. The Clean Energy Finance
Corporation will manage the Fund. It is unclear how the Reef Fund will directly
benefit the health of the GBR in the short to medium term. It will not fund
projects primarily designed to improve water quality, although improvements to
water quality may arise as a secondary benefit from some of the clean energy
The policy cites examples of projects that will be
funded such as:
- solar panels to substitute for diesel on a farm and
- more energy efficient pesticide sprayers
and fertiliser application systems.
GBRMPA, Great Barrier Reef Outlook Report 2014, 2014
Australian and Queensland Governments, Reef 2050 Long-term Sustainability Plan, 2015
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