MTSRF Synthesis Report
Stephanie J. Duce, Kevin E. Parnell, Scott G. Smithers and Karen
E. McNamara
James Cook University, Townsville
ISBN 978-1-921359-53-8
Published November 2010
MTSRF Project 1.3.1 -
Traditional knowledge systems and climate change in the Torres
Strait
Executive Summary
This report provides a synthesis of research on climate change
and coastal science in the Torres Strait, and has been produced for
the Australian Government's Marine and Tropical Sciences Research
Facility (MTSRF). It identifies and summarises work to date
on reef evolution, hydrodynamics and sedimentary environments
throughout the Torres Strait. It describes the island dynamics at
Boigu, Saibai, Masig, Poruma, Warraber and Iama Islands. Numerous
studies relating to climatic change are reviewed and the most
relevant regional predictions for climate change in the Torres
Strait are presented. The potential physical and ecological impacts
of these changes in the Torres Strait are also identified.
Adaptation and mitigation measures are suggested and their outcomes
and consequences are evaluated. The key principles from sustainable
land use plans on the islands are summarised and knowledge gaps in
the fields of both coastal and climatic science are identified to
guide future research.
The most important factor influencing the hydrodynamics of the
islands of the Torres Strait is the seasonally reversing wind
regime, characterised by dominant southeasterlies for nine months
of the year (March to November) and northwesterlies over the summer
months (November to March). The tidal regime through the Torres
Strait is complex and is also fundamental to the morphodynamics of
the islands. Surge events are characterised by an elevation of mean
water level caused by pressure and wind set up, often resulting
from storms some distance away. Such events occur in the Torres
Strait and are responsible for much of the geomorphic work
performed on the island beaches. Summaries of island dynamics are
described for those locations at which data are available, and the
areas vulnerable to coastal erosion and inundation are
identified.
Climate change is expected to result in the warming of average
air and ocean temperatures, average global sea level rise, ocean
acidification and regional changes to wind and precipitation
patterns and extreme weather events. It was recognised that the
exact nature and rates of these changes remain uncertain
particularly at regional and local scales. In Torres Strait the
best available estimates suggest that local air temperatures will
increase by 1-4°C and sea surface temperatures by up to 3°C
by the year 2070. Sea level rise of up to one metre is also
projected to occur by the year 2100. Other changes in regional
climatic conditions predicted include a ten percent increase in
downwards radiation, between 0.8 and 13% increase in wet season
rainfall, between 3.9 and 23% decrease in dry season rainfall, and
a 16% increase in evapotranspiration by the year 2070. Wind speed
is expected to increase by between two and five percent by 2030,
accompanied by uncertain changes to wind direction trends.
Ecological impacts on the health of coral reef and seagrass
communities, as well as species of concern including turtles and
dugongs, in the Torres Strait are predicted to result from these
climatic changes. These impacts include increased coral bleaching
events, a temperature induced decline in turtle hatchling survival
and an imbalance in the gender of hatchlings.
The most concerning immediate physical impacts likely to
result from these climatic changes relate to inundation affecting
island infrastructure, vegetation and water sources and coastal
erosion threatening infrastructure and sites of cultural
significance. The exact nature of these impacts will vary from
island to island. In some cases, sea level rise could potentially
increase the transport of sediment from reef flats to islands,
causing them to grow. However, in general, these impacts will
decrease the amount of viable land on islands and, unless managed
well, will cause decline in the quality of life for the communities
of Torres Strait. Relocation to higher ground must be planned and
the potential relocation of some communities must be considered.
This report identifies numerous adaptation and mitigation measures,
including hard and soft engineered works, which can minimise these
physical impacts and even improve island condition. These must be
considered on an island by island basis to ensure they are
successful and that the negative consequences are understood,
minimised and acceptable to the communities
