AGAINST ALL ODDS PACIFIC ISLANDS DEFY SEA LEVEL RISE

January 05, 2019

Against the odds, a number of shape-shifting islands in the middle of the Pacific Ocean are standing up to the effects of climate change and sea level rise.
Paul Kench at the University of Auckland in New Zealand and Arthur Webb at the South Pacific Applied Geoscience Commission in Fiji used historical aerial photos and high-resolution satellite images to study changes in the land surface of 27 Pacific islands over the last 60 years. During that time, local sea levels have risen by 120 millimetres, or 2 millimetres per year on average. For years, people have warned that the smallest nations on the planet – island states that barely rise out of the ocean – face being wiped off the map by rising sea levels. Now the first analysis of the data broadly suggests the opposite: most have remained stable over the last 60 years, while some have even grown.
But while global temperatures are up – 2017 was the second hottest year on record – and sea levels in the Pacific are rising, Tuvalu isn’t shrinking. In fact, it’s getting bigger, according to a new study published in the journal Nature Communications.
“Results highlight a net increase in land area in Tuvalu of 73.5?ha (2.9%), despite sea-level rise, and land area increase in eight of nine atolls,” the team wrote.
The study looked at all 101 atolls that make up the island nation, and found that 74 percent grew over the past four decades in spite of rising sea levels. The remainder of the islands shrunk as expected.
“We tend to think of Pacific atolls as static landforms that will simply be inundated as sea levels rise, but there is growing evidence these islands are geologically dynamic and are constantly chang
ing,” co-author Dr. Paul S. Kench of the University of Auckland said in a press release. “The study findings may seem counterintuitive, given that (the) sea level has been rising in the region over the past half century, but the dominant mode of change over that time on Tuvalu has been expansion, not erosion.”
The land gains appear to have come from a combination of new sedimentation and wave processes, the scientists found.
Although the study confirmed that climate change is a challenge that Pacific islands will face in the coming decades, the study shows that there is still plenty to learn about how Pacific atolls gain and lose land.
In the meantime, residents of Tuvalu can begin planning for a future that doesn’t include the forced migration foreseen by climate scientists. Still, changes in the land and its resources may require some shifts in how the island nation’s population sustains itself, the researchers warned.
(Source: phys.org/nature.com/Space Daily)