Going, going, gone. Five of the Solomon Islands have been swallowed whole by rising sea levels, offering a glimpse into the future of other low-lying nations.

Sea levels in the Solomon Islands have been climbing by 7 millimetres per year over the last two decades, due to a double whammy of global warming and stronger trade winds.

“It’s a perfect storm,” says Simon Albert of the University of Queensland. “There’s the background level of global sea-level rise, and then the added pressure of a natural trade wind cycle that has been physically pushing water into the Western Pacific.”

The global rate of sea level rise is 3 millimetres per year, but is likely to accelerate to 7 by the end of the century, as rising temperatures melt ice sheets and cause thermal expansion of the oceans, Albert says.

“All the projections show that in the second half of the century, the rest of the globe will reach the rate of sea level rise that the Solomon Islands is currently experiencing,” he says.

Albert and his colleagues analysed aerial and satellite images from 1947 to 2014 to study the effects of creeping sea levels on the coastlines of 33 reef islands in the Solomons.

Five islands present in 1947, ranging in size from 1 to 5 hectares, had completely disappeared by 2014.

Another six islands had shrunk by 20 to 62 per cent in the same period, confirming anecdotal reports of people living in the area.

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New Scientist

Rising seas are eating away at small islands and will eventually turn their inhabitants into climate refugees, right? Not so for some of the world’s most threatened islands, which have grown despite experiencing dramatic sea level rise.

Funafuti atoll, which includes the capital of Tuvalu, is an islet archipelago in the tropical Pacific Ocean made from coral debris washed up from an underlying reef by waves, winds and currents. Over the past 60 years the sea has risen by around 30 centimetres locally,sparking warnings that the atoll is set to disappear.

But Paul Kench of the University of Auckland, New Zealand, and colleagues found no evidence of heightened erosion. After poring over more than a century’s worth of data, including old maps and aerial and satellite imagery, they conclude that 18 out of 29 islands have actually grown.

As a whole, the group grew by more than 18 hectares, while many islands changed shape or shifted sideways.

“There is still considerable speculation that islands will disappear as sea level rises,” says Kench. “Our data indicates that the future of islands is significantly different.”

Storms and other disturbances that churn up the sea seem to be more important than sea level in influencing stability, says Kench. Storms break up coral, which then gets deposited on the atolls. He says other coral reef islands are likely to evolve in the same way, and that the Maldives seem to be showing a similar effect.

“There is presently no evidence that these islands are going to sink,” says Virginie Duvat of the University of La Rochelle in France. She says that she and other researchers are trying to fight the widespread misconception that sea level rise will mean the end for atolls. However, Kench’s findings do not apply to other types of island, like the volcanic main islands of Fiji, Tonga and Samoa.

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New Scientist

A massive rise in sea level is coming, and it will trigger climate chaos around the world. That was the message from a controversial recent paper by climate scientist James Hansen. It was slated by many for assuming – rather than showing – that sea level could rise between 1 and 5 metres by 2100.

But now, just a week after being formally published, it is being backed up by another study. “He was speculating on massive fresh water discharge to the ocean that I don’t think anybody thought was possible before,” says Rob DeConto of the University of Massachusetts Amherst. “Now we’re publishing a paper that says these rates of fresh water input are possible.”

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New Scientist