Five Pacific islands go under
Sea levels are rising faster in the Solomon Islands -
and send a warning to the rest of the world.:
by Simon Albert, Alistair Grinham, Badin Gibbes,
Javier Leon, John Church
Sea-level rise, erosion and coastal flooding are some of the greatest
challenges facing humanity from climate change. Recently at least five
reef islands in the remote Solomon Islands have been lost completely to
sea-level rise and coastal erosion, and a further six islands have been
severely eroded.
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.
This is the first scientific evidence, published in Environmental
Research Letters, that confirms the numerous anecdotal accounts from
across the Pacific of the dramatic impacts of climate change on
coastlines and people.
A warning for the world
Previous studies examining the risk of coastal inundation in the
Pacific region have found that islands can actually keep pace with
sea-level rise and sometimes even expand.
However, these studies have been conducted in areas of the Pacific
with rates of sea level rise of 3-5 mm per year - broadly in line with
the global average of 3 mm per year.
For the past 20 years, the Solomon Islands have been a hotspot for
sea-level rise. Here the sea has risen at almost three times the global
average, around 7-10 mm per year since 1993. This higher local rate is
partly the result of natural climate variability.
These higher rates are in line with what we can expect across much of
the Pacific in the second half of this century as a result of
human-induced sea-level rise. 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.
Natural variations and geological movements will be superimposed on
these higher rates of global average sea level rise, resulting in
periods when local rates of rise will be substantially larger than that
recently observed in Solomon Islands. We can therefore see the current
conditions in Solomon Islands as an insight into the future impacts of
accelerated sea-level rise.
We studied the coastlines of 33 reef islands using aerial and
satellite imagery from 1947-2015. This information was integrated with
local traditional knowledge, radiocarbon dating of trees, sea-level
records, and wave models.
Waves add to damage
Wave energy appears to play an important role in the dramatic coastal
erosion observed in Solomon Islands. Islands exposed to higher wave
energy in addition to sea-level rise experienced greatly accelerated
loss compared with more sheltered islands.
Twelve islands we studied in a low wave energy area of Solomon
Islands experienced little noticeable change in shorelines despite being
exposed to similar sea-level rise. However, of the 21 islands exposed to
higher wave energy, five completely disappeared and a further six
islands eroded substantially.
The human story
These rapid changes to shorelines observed in Solomon Islands have
led to the relocation of several coastal communities that have inhabited
these areas for generations. These are not planned relocations led by
governments or supported by international climate funds, but are ad hoc
relocations using their own limited resources.
The customary land tenure (native title) system in Solomon Islands
has provided a safety net for these displaced communities. In fact, in
some cases entire communities have left coastal villages that were
established in the early 1900s by missionaries, and retraced their
ancestral movements to resettle old inland village sites used by their
forefathers. In other cases, relocations have been more ad hoc, with
individual families resettling small inland hamlets over which they have
customary ownership. In these cases, communities of 100-200 people have
fragmented into handfuls of tiny family hamlets. Sirilo Sutaroti, the
94-year-old chief of the Paurata tribe, recently abandoned his village.
"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," he told us.
The global effort
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.
Interactions between sea-level rise, waves, and the large range of
responses observed in Solomon Islands - from total island loss to
relative stability - shows the importance of integrating local
assessments with traditional knowledge when planning for sea-level rise
and climate change.
Linking this rich knowledge and inherent resilience in the people
with technical assessments and climate funding is critical to guiding
adaptation efforts.
Melchior Mataki who chairs the Solomon Islands' National Disaster
Council, said: "This ultimately calls for support from development
partners and international financial mechanisms such as the Green
Climate Fund. This support should include nationally driven scientific
studies to inform adaptation planning to address the impacts of climate
change in Solomon Islands."
Last month, the Solomon Islands government joined 11 other small
Pacific Island nations in signing the Paris climate agreement in New
York. There is a sense of optimism among these nations that this
signifies a turning point in global efforts.
However, it remains to be seen how the hundreds of billions of
dollars promised through global funding models such as the Green Climate
Fund can support those most in need in remote communities, like those in
Solomon Islands.
- Third World Network Features
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