Five Pacific islands have already disappeared due to sea level rise

Sea level rise and other associated impacts of rising global temperatures such as coastal erosion and flooding have long been forecast as some of the most serious challenges that humanity will face due to climate change, but for most of the world those are challenges to be dealt with in the future.

For the Solomon Islands, an archipelago of hundreds of islands in the South Pacific, however, those impacts are already very real.

According to a study published last week in the journal Environmental Research Letters, five reef islands in the Solomon Islands have been completely lost to sea-level rise and coastal erosion, and six more islands have suffered severe erosion. This is believed to be the first scientific evidence confirming the impacts climate change is having on Pacific islands.

A team of Australian researchers led by scientists at The University of Queensland used a series of aerial and satellite imagery of 33 islands collected from 1947 to 2014, together with local traditional knowledge, to identify the five vegetated reef islands that have vanished and the other islands that have experienced substantial shoreline erosion.

“Shoreline recession at two sites has destroyed villages that have existed since at least 1935, leading to community relocations,” the authors of the study write.

Rates of shoreline erosion are notably higher in areas exposed to high wave energy, they found, which indicates that there may be a “synergistic interaction” between sea level rise and waves. “Understanding these local factors that increase the susceptibility of islands to coastal erosion is critical to guide adaptation responses for these remote Pacific communities,” the authors added.

In an article for The Conversation, the authors discuss in more detail just what has been lost and the impacts to local communities. “These islands lost to the sea range in size from one to five hectares. They supported dense tropical vegetation that was at least 300 years old. Nuatambu Island, home to 25 families, has lost more than half of its habitable area, with 11 houses washed into the sea since 2011.”

Many coastal communities have been forced to relocate to inland villages, often on an ad hoc basis with no support from local government or international climate funds, the researchers said. “In addition to these village relocations, Taro, the capital of Choiseul Province, is set to become the first provincial capital in the world to relocate residents and services in response to the impact of sea-level rise.”

While previous studies have found that islands can actually keep pace with sea-level rise and in some cases can even expand, those studies were conducted in areas of the Pacific with rates of sea level rise that were just three to five millimeters per year, which is mostly in line with the global average of three millimeters per year, the researchers said.

The Solomon Islands have been a hotspot for sea-level rise for the past two decades, however. The sea has risen there at almost three times the global average, or about seven to 10 millimeters per year since 1993.

This higher local rate in the Solomon Islands is partly due to natural climate variability, but is a portent of what we can expect across much of the Pacific in the second half of this century as a result of sea level rise due to rising global temperatures, the researchers said. “Many areas will experience long-term rates of sea-level rise similar to that already experienced in Solomon Islands in all but the very lowest-emission scenarios.”

That’s because those natural variations and geological movements will be “superimposed” on the higher rates of global average sea level rise caused by climate change, which will possibly result in some coastal locations around the world experiencing substantially higher rates of sea level rise than those recently observed in the Solomon Islands.

“We can therefore see the current conditions in Solomon Islands as an insight into the future impacts of accelerated sea-level rise,” the researchers concluded.

Countries have pledged hundreds of billions of dollars to global funding models such as the Green Climate Fund to support people living in remote communities that are suffering the worst impacts of climate change. But it remains to be seen if or how those funds will be mobilized to help the climate refugees of the Solomon Islands.

“This ultimately calls for support from development partners and international financial mechanisms such as the Green Climate Fund,” Melchior Mataki, chair of the Solomon Islands’ National Disaster Council, said in The Conversation article. Mataki was not involved in the study. “This support should include nationally driven scientific studies to inform adaptation planning to address the impacts of climate change in Solomon Islands.”

Source: Mongabay