2021-10-08 SM - Item 1 - Attachment 1 - Draft Coastal Hazards Adaptation Plan

         Developing this plan
This section discusses Phases 2 to Phase 7 of the CHAP’s development, including the methods
used to complete each phase, as well as their respective outputs.


Understanding climate change & sea level rise
The Earth’s atmosphere has warmed significantly over the past 200 years, and this is largely due
to human activities that have significantly increased the amount of greenhouse gases (GHG) in the
atmosphere. The rise in the concentration of greenhouse gases in the atmosphere is trapping more
heat within the Earth’s climate system than would otherwise have occurred without the increases in
these gases. This is in turn causing land and oceans to warm at a rate much faster than has
occurred naturally in the past3.

Based on the available science, the factor with the most influence on coastal hazards due to
climate change is rising sea levels. Sea level rise is the elevation of global and local mean sea
level caused by the expansion of the ocean as it warms, and the transfer of water currently stored
on land to the ocean, particularly from melting glaciers and ice sheets. Global sea levels are rising
at an increasingly higher rate than in the past 2000 years. Sea levels started rising at the 1800s
following the industrial revolution and as a result of increased dependency on fossil fuels. Between
1901 and 1990 the rate of global average sea level rise was 1.3-1.7mm annually, increasing to 1.8-
3.6 mm per year between 1993 and 2010 (IPCC 2014).

The result of this sea level rise is more land area exposed to coastal erosion and inundation over
time.



Phase 2 – 3: Identifying the hazards
The first stage in developing a risk-based plan to respond to coastal hazards is to model and map
the expected behaviour of each hazard. Modelling of a range of hazard events was performed by
expert consultants, consistent with the QCoast2100 guidelines and Queensland Government
technical guidelines. The future climate scenario underpinning the hazard modelling is based upon
a high global greenhouse gas emissions scenario known as ‘RCP 8.5’, which is often referred to as
‘business as usual’ because it broadly represents an emissions pathway based on our current
trajectory of minimal emissions reduction. This scenario results in a projected rise in regional mean
sea level of approximately +0.8 meters by the year 21004. This scenario represents minimal action
being taken globally to reduce global greenhouse emissions between now and the year 2100. The
adoption of this scenario is a requirement of the QCoast2100 program.

Council acknowledges the need to consider a range of possible climate change scenarios as well
as sources of local data in coastal hazard modelling and for these to be incorporated as part of
future modelling reviews where appropriate.
Ongoing localised monitoring and data collection are important inputs to managing coastal hazard
risks, and are discussed further in Section 6 of this plan.



Noosa already experiences periodic tidal inundation and coastal erosion events. The first stage of
the project sought to understand how Noosa may be affected by changes in tidal water, storm

3 https://climate.nasa.gov/evidence/
4 Intermediate projections for sea level rise are +0.2m by the year 2040, and +0.5m by the year 2070.


Noosa Council – Coastal Hazards Adaptation Plan                                                     Page 11