Climate change sinks islands in the Solomons

A beach in the Solomons - perhaps not long for this world (Getty)
A beach in the Solomons - perhaps not long for this world (Getty)

Five entire islands in the Solomons have gone underwater in recent years, and six more are slowly being swallowed.

Scientists combined satellite and aerial imagery dating back to the 1940s with local knowledge and data, to show how rising sea levels and coastal erosion have eaten away at the Pacific island chain.

Writing in journal Environmental Letters, they say the sea around the Solomons has risen between 7mm and 10mm a year since 1994.

The study focused on two areas, Isabel and Roviana, consisting of 33 islands. Of the original 20 reef islands in Isabel, five had been completely eroded away. Another six were 20 percent or more smaller than they were in the 1940s -- two of them losing more than half their size.

Of those in Roviana, six increased in size slightly (due to improved coral cover) and six decreased.

More than half the houses on the 33rd island, that of Nuatambu, have been washed away, with residents saying the damage was incremental -- not the result of a particular adverse weather event -- and happening "over several years".

In 1962 it measured just over 30 square kilometres. In 2014, it had shrunk to just under 14.

Climate change sinks islands in the Solomons

How Nuatambu has shrunk over the years (supplied)

Some residents have been forced to relocate to neighbouring volcanic island Choiseul, but others have built temporary housing further inland.

In Mararo, a village on Malaita, the entire community decided to up sticks and move 20m further inland.

"The sea has started to come inland, it forced us to move up to the hilltop and rebuild our village there away from the sea," Sirilo Sutaroti, 94-year-old chief of the Paurata tribe, told the researchers.

Islands exposed to higher sea rises predictably showed greater loss, but wave strength was also a factor, with islands exposed to bigger waves suffering greater erosion.

Climate change sinks islands in the Solomons

One of the former islands, now underwater (supplied)

Sea levels are rising faster now than they were mid-20th century. In 1950 the rise was estimated at 3mm a year, rising to between 7mm and 10mm in the last two decades, which have also seen world temperatures hit historical highs.

"Climate change induced sea-level rise is anticipated to be one of the greatest challenges for humanity over the coming century," the scientists claim.

"Whilst it has been shown that sediment accretion may help atoll reef islands adapt to higher sea levels over recent decades, it is likely current rates of sea-level rise will be exceeded during this century."

Earthquakes and volcanoes also threaten the island chain, with an 8.1 shake in 2007 subsiding some reef islands by up to 60cm.