Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search

 

Low-lying Pacific Island Has More Land Above Sea Level Than In 1943

An inhabited island in the low-lying Pacific nation of the Marshall Islands, which are thought to be at risk of being inundated by rising sea levels, has actually increased in size since 1943, scientists say.

And the increase in area above sea level is likely not confined to Jeh Island on Ailinglaplap Atoll, one of 29 coral reef atolls that form the Republic of the Marshall Islands which lie roughly half way between Hawaii and Australia. The low-lying Islands have been called the most endangered nation on earth due to the potential effects of sea level rise.

Atoll islands like those in the Marshall Islands are low-lying deposits of reef-derived sediments deposited in the last 5000 years or less. Despite local sea level rise, scientists have observed growth in land area of most atolls since the mid-20th century, suggesting they are able to accumulate the sediment needed to expand.

But this process of aggregation of sediment is not well understood. In particular, little research has been done to establish whether sediment deposits which accumulate on coral atolls are recent deposits or sediment that has built up over many decades.

In a new study Dr Murray Ford from the University of Auckland and Professor Paul Kench from Simon Fraser University in Canada compared aerial photographs from 1943 and used satellite imagery and radiocarbon dating of sediment deposits on Jeh Island.

Photographs and satellite images show the island, sparsely populated with about 40 homes, has increased in land area by 13 per cent since 1943, from 2.02 sq km to 2.26 sq km, reaching 2.28 sq km by 2015. It also appears Jeh is a merger of at least two formerly separate islands where sediment has built high enough to form one larger continuous land area.

As well, satellite images from 2010, 2015 and 2019 reveal a spit at the western-most end is continuing to extend, adding to the total land area above sea level.

In trying to track where the island-building sediment is from and how long ago it accumulated, the ages of sediment samples were calculated using radiocarbon dating. The team tested coral fragments, mollusc shells and microscopic marine organisms called foraminifera at the Island’s western end.

In total 28 radiocarbon dates of island sediments were analysed which showed accretion of sediment deposits was from more recent material, generally post-1950.

“This study has found that the expansion of islands through sediment generation under conditions of sea level rise is possible,” Dr Ford says.

“The coral reefs which surround these islands is the engine room of island growth, producing sediment which is washed up on the island shoreline. Healthy coral reefs are essential for this process to continue into the future.

“In this work and in previous studies, we have found Islands are resilient in the face of rising seas and that sediment supply to some atolls is out-pacing sea level rise. What we don’t know is how that will play out in coming decades but studies of low-lying reef island formation do need to take these findings into account.”

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 

TradeMe: Property Prices In Every Region Hit New High For The Very First Time

Property prices experienced their hottest month on record in December, with record highs in every region, according to the latest Trade Me Property Price Index.\ Trade Me Property spokesperson Logan Mudge said the property market ended the year with ... More>>

Motor Industry Association: 2020 New Vehicle Registrations Suffer From Covid-19

Chief Executive David Crawford says that like some other sectors of the New Zealand economy, the new vehicle sector suffered from a case of Covid-19. Confirmed figures for December 2020 show registrations of 8,383 were 25% ... More>>

CTU 2021 Work Life Survey: COVID And Bullying Hit Workplaces Hard, Huge Support For Increased Sick Leave

New data from the CTU’s annual work life survey shows a snapshot of working people’s experiences and outlook heading out of 2020 and into the new year. Concerningly 42% of respondents cite workplace bullying as an issue in their workplace - a number ... More>>

Smelter: Tiwai Deal Gives Time For Managed Transition

Today’s deal between Meridian and Rio Tinto for the Tiwai smelter to remain open another four years provides time for a managed transition for Southland. “The deal provides welcome certainty to the Southland community by protecting jobs and incomes as the region plans for the future. The Government is committed to working on a managed transition with the local community,” Grant Robertson said. More>>

ALSO:

OECD: Area Employment Rate Rose By 1.9 Percentage Points In The Third Quarter Of 2020

OECD area employment rate rose by 1.9 percentage points in the third quarter of 2020, but remained 2.5 percentage points below its pre-pandemic level The OECD area [1] employment rate – the share of the working-age population with jobs – rose ... More>>

Economy: Strong Job Ad Performance In Quarter Four

SEEK Quarterly Employment Report data shows a positive q/q performance with a 19% national growth in jobs advertised during Q4 2020, which includes October, November and December. Comparing quarter 4, 2020, with the same quarter in 2019 shows that job ad volumes are 7% lower...More>>

NIWA: 2020 - NZ’s 7th-warmest Year On Record

The nationwide average temperature for 2020, calculated using stations in NIWA’s seven-station temperature series which began in 1909, was 13.24°C (0.63°C above the 1981–2010 annual average). New Zealand’s hottest year on record remains 2016, when... More>>

Quotable Value New Zealand: Property Market Set To Cool From Sizzling To Warm In 2021

Nostradamus himself could not have predicted the strange series of events that befell our world in 2020 – nor the wild trajectory of New Zealand’s property market, which has gone from “doom and gloom” to “boom and Zoom” in record time. Even ... More>>