1. Introduction

1.1 What is Sea level rise?

Sea level rise (SLR) is the rise in water levels in the world’s oceans caused by global warming. As the oceans warm due to global warming, the water expands, causing sea levels to increase. Global warming and rising average temperatures are also forcing glaciers and ice sheets to melt at a faster rate than usual, resulting in an increase in ocean water levels. SLR is a global hazard to coastal life (National Geographic 2022).

The Intergovernmental Panel on Climate Change (IPCC) has predicted a 79 centimeter rise in sea level by 2100, putting coastal development at danger. Coastal areas are crucial ecological spaces because they serve to minimise erosion and pollution while also providing food, shelter, breeding areas, and nursing grounds for a diverse range of organisms. Coastal locations are important for enterprises because they give water space for shipping and ports, as well as recreational activities like fishing and diving plus raw resources like salt and sand. Many communities have residential sections along the coast. As water levels rise, it is critical to understand what will happen to all of these crucial sites along the coast. (Creel 2003).

SLR causes increasing storm surge intensity and floods that damage coastal regions. There are multiple metropolitan centres and huge populations located near coastlines, as well as a variety of coastal species that is vulnerable and threatened by SLR. It will have an impact further inland, polluting groundwater as saltwater seepage increases. This is an issue that requires close monitoring and coastal area preparation for the implications (National Geographic 2022).

1.2 Impacts of Sea Level Rise

SLR is a serious threat to the world since the bulk of the population lives near the shore and the infrastructure to support that population is also located near the coast. 60% of the world’s 39 metropolises with populations greater than 5 million are located within 100 kilometres of the coast (Fig. 1), including 12 of the world’s 16 cities with populations greater than 10 million (IPCC 2007). Living by the seaside increases the risk to life and property. Furthermore, in the last 20 years, there has been a growing trend of individuals flocking to the seaside. “According to Nicholls and Mimura (1998), 600 million people will live in coastal floodplain area below the flood level by 2100.” (Boateng 2008)

In addition to this coast being the most productive source, SLR will have an influence on the global economy and population. The following are the effects of SLR on the coastal zone (Boateng 2008):

• Inundation increasing (flooding) into the coastal land, can cause loss property and life.

• Frequent storm surges can cause destruction of the beaches and severe destruction and erosion of shoreline along with destruction of life and property close to the shore.

• Increased coastal erosion can lead to destruction of coastal properties and loss of life.

• SLR can cause reduction in water supply to towns, this will be caused by seawater intruding into the groundwater and fresh water sources.

• SLR will cause a change in estuaries and tidal river systems, destroying ecosystems and patterns of sedimentation

1.3 Australia’s Coastline

Australia is a coastal society, 85% of the population lives in coastal regions (Fig. 2), and the shore is extremely important - socially, economically, and environmentally. All of Australia’s state capital cities are located along the coast and are connected to networks for the nation’s exports and imports, as well as other commercial activity. Australians love the leisure afforded by the seashore, which is also a treasure trove of environmental assets that contribute to the importance of ecosystems (Department of Climate Change 2009).

Beaches, coral reefs, wetlands, estuaries, and low-lying places in Australia will all experience changes as a result of climate change. There is insufficient knowledge about the extent to which wetlands can aid in the flooding of low-lying areas for regional decision making (Department of Climate Change 2009).

If sea levels rise by 1.1 metres, about 40,800 to 62,400 residential properties in New South Wales will be inundated. The eastern coast of New South Wales experiences significant erosion and storm surges, as well as flooding into estuaries. Tropical cyclones have similar effects and flood low-lying agricultural regions and towns along NSW’s north-eastern coast (Department of Climate Change 2009).

Byron Shire is one such region on the north eastern coast of New South Wales. .