Sea level rise around New Zealand doubles in past 60 years

Climate change has been identified as the main cause of the sea levels around New Zealand rising twice as quickly in the previous 60 years as they did in the first half of the 20th century. At three of the four sites being monitored—Wellington, Lyttelton, and Dunedin—Stats NZ's recently updated coastal sea level rise indicator shows the pace doubled between 1961 and 2020 compared to the mean rate from 1901–1960. The capital city, Wellington, experienced the most significant surge over the past 60 years, of 2.84mm a year, while Lyttelton, near Christchurch, had the highest overall trend over the past 120 years, at 2.24mm a year. The metric took into consideration any regional variations in vertical ground movement, which might be brought on by subsidence-causing geological processes or human activity. Climate change was cited as one of the main causes of the sea level rise. As greenhouse gas emissions warm the Earth’s atmosphere, heat is absorbed by the ocean, Stats NZ said, adding that the expansion of seawater as it warms, combined with increased sea volume caused by the melting of glaciers and ice sheets, all contribute to sea level rise. “Future climate change projections indicate that sea levels will continue to rise,” said Michele Lloyd, Stats NZ’s environmental and agricultural spokesperson. “Rising sea levels affect coastal communities, infrastructure, coastal habitats, and biodiversity.” The coastline of New Zealand is extensive, and many homes are constructed close to the water. One in seven citizens, or 675,000 people, reside in flood-prone zones, while another 72,065 do so in locations where significant sea level rise is predicted. At least 10,000 homes in New Zealand's largest cities would effectively be uninsurable by 2050, according to a government-funded report by Deep South Challenge, a national science collaboration. Local Government New Zealand estimates the amount of local infrastructure exposed to sea level rise to be about $14 billion.