Sea level rise limits adaptation options

Sea levels are rising twice as fast as expected in parts of two-island New Zealand, threatening the country’s two largest cities, Auckland and Wellington, according to a government research program released Monday (May 2). Dubbed NZ SeaRise (literally “New Zealand Sea Level Rise”), the government-funded study program is a five-year study program carried out by both national and international scientists.

An alarming document

The expansion of the ocean and the melting of glaciers are responsible for the increase in water levels. “When you heat water, it takes up more space. Since we can’t sink the ocean floor, it is the sea level that rises.” The charts are drawn by Eric Gilliardi, an oceanographer and climatologist at the National Center for Scientific Research. “We succeed in projecting sea level rise under scenarios of increasing greenhouse gas emissions on a global scale. But once we get back to the local level, it becomes more complicated,” he thinks.

In New Zealand, not only is the water level rising, but the land is also receding. New Zealand sits on top of the Pacific Fire, a moving volcanic land that, between two earthquakes, tends to sink in certain areas of the country. But it is difficult to predict the local depression of the ribs. Reports Benoît Mesignac, a researcher at the National Center for Space Studies (Cnes) and at the Laboratory of Geophysics and Space Oceanography (Legos) in Toulouse.

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While experts have predicted a sea level rise of 30cm on some of New Zealand’s coasts in 2060, new data from NZ SeaRise shows that this rise could happen as early as 2040. Wellington could thus be the victim of an annual flood that causes damage.

Thus, the authorities have less time than expected to organize adaptation to the consequences of climate change. The adaptation plan currently being developed, which includes the relocation of some populations and infrastructures, must be reviewed.

Concretely, this “It takes years, forty or sixty years »explains Gonnery Le Cossanet, a researcher with the Bureau of Geological Research and Mining (BRGM) and co-author of Part Two of the sixth report of the Intergovernmental Panel on Climate Change (IPCC). In the case of Venice’s Moss Barrier (the unit that prevents flooding in Venice during high tide). This adaptation took years.