A storm cloud passes over bathers who prepare to leave Sydney's Manly Beach
A storm cloud passes over bathers who prepare to leave Sydney's Manly Beach during an afternoon storm March 5, 2014. The storm, which generated little rain but high gusts of wind, was blown out to sea. REUTERS/Will Burgess

New Zealand's infrastructure on low-lying areas and coastal properties are under threat from sea level rises as much as 30 centimetres. A new environment report has warned that rising sea levels due to global warming will have a significant impact to the people of New Zealand.

In a report released by Parliamentary Commissioner for the Environment Jan Wright, three factors were identified as causing the waters to rise. The melting ice sheets in Antarctica and Greenland, shrinking glaciers and expanding seawater contribute to sea level rise. Wright's peer-reviewed report analysed about 200 years of studies on sea levels.

According to Wright's report, global sea levels had increased 20 cm in the last 100 years. Citing the previous research of the Intergovernmental Panel on Climate Change, the commissioner said another 20cm to 40cm increase in sea level is expected by 2050. Wright believes sea levels will rise regardless of international efforts to reduce greenhouse gas emissions. She said New Zealand will have to adapt when the oceans rise again.

Although some may think a rise of 30cm is small, Wright warned it could be costly to land owners especially in low-lying areas. The report said the evidence of how the rise in sea levels affect the coast can be observed during storm surges as the wind and waves push water towards the coast.

New Zealanders are warned to expect severe floods in the future like the one in Auckland in 2011 when a storm surge caused floods and damaged $7 million worth of property. According to New Zealand's weather bureau, a similar storm would strike the country every 10 years by 2040 and every year decades later.

Wright's report also revealed that Christchurch has already seen the impact as earthquakes have increased the region's vulnerability to storm surges and floods as a result of land loss. She said the councils have the responsibility to manage the risk.

According to RadioNZ, the Ministry for the Environment has already released guidelines for councils to help their regions prepare. The Local Government New Zealand has expressed their need for more direction from the government.