Increased sea levels

2016

Changes in sea level are pressuring coastal locations. Coastal infrastructure is affected, and, when the sea encroaches further onto the land, space for development is reduced. It may also reduce the amenity of the region—for example, by reducing the amount of sand available on beaches such as on the Gold Coast.

Projections indicate that, around the Australian coast, the rate of sea level rise during the 21st century will be greater than the average rate during the 20th century, as radiative forcing from increasing greenhouse gas emissions continues. This result applies even for the lowest emissions scenario, RCP2.6, which would require significant mitigation measures. For the first decades of the 21st century, the projections are almost independent of the RCP chosen (Table BLT7), but they begin to separate significantly from about 2050 (CSIRO & BoM 2015).

Table BLT7 Minimum height (metres) that structures would need to be raised, selected locations, in 2030, 2050, 2070 and 2090

Location

2030

2050

2070

2090

Darwin

0.12–0.13

0.21–0.26

0.32–0.45

0.43–0.71

Port Hedland

0.12–0.13

0.21–0.26

0.32–0.44

0.43–0.70

Geraldton

0.12–0.13

0.22–0.27

0.35–0.48

0.49–0.78

Fremantle

0.12–0.13

0.22–0.26

0.34–0.47

0.47–0.76

Bunbury

0.12–0.13

0.22–0.27

0.34–0.47

0.47–0.75

Albany

0.13–0.14

0.24–0.28

0.36–0.50

0.50–0.81

Port Adelaide

0.13–0.14

0.24–0.28

0.36–0.50

0.50–0.81

Victor Harbor

0.12–0.13

0.21–0.25

0.32–0.44

0.43–0.69

Sydney

0.14–0.15

0.24–0.30

0.35–0.52

0.48–0.84

Newcastle

0.14–0.15

0.24–0.30

0.36–0.53

0.49–0.86

Mackay

0.13–0.14

0.22–0.28

0.33–0.47

0.43–0.73

Townsville

0.13–0.14

0.23–0.28

0.33–0.47

0.44–0.74

Note: Covers all Representative Concentration Pathway emissions scenarios.

Source: CSIRO & BoM (2015)

The projected sea level allowances guide the amount of sea level rise that should be considered for future planning and adaptation activities to ensure that the frequency of future extreme sea level exceedances will remain unchanged from present conditions. For 2030, the current rate of sea level exceedances can be preserved by adopting a median sea level rise scenario, but, by 2090, a value higher than the median sea level rise projection will be necessary (high confidence).

 

 

Photo of aerial view of Sydney suburbs

Aerial view, Sydney suburbs (Photo by Jenny Tomkins)

Coleman S (2016). Built environment: Increased sea levels. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/built-environment/topic/2016/increased-sea-levels, DOI 10.4226/94/58b65a5037ed8