Islands going under

  • Environment
  • Tuesday, 30 Jul 2013

Global warming forces change in lifestyle for Pacific islanders.

THE Micronesian island state of Yap is small and remote. “Paradise, if you can find it,” the Los Angeles Times once wrote.

But there’s trouble in paradise. Queens University of Charlotte science professor Reed Perkins says global climate change has triggered a domino effect that he has witnessed on Yap, resulting in decreased food supply amid increasing demand. Perkins and others are using the latest technology in hopes of devising an adaptation strategy that could have future benefits locally and worldwide.

Perkins returned June 2 from Yap (population 7,000), where Queens staff and students have built long-term data sets in visits since 2001. With only 214sqkm of land, Yap consists of three high islands and about 133 low-lying coralline atolls – ring-like islands and reefs that nearly or entirely enclose a lagoon – scattered over 258,000sqkm of ocean.

About 45% of Yap state’s growing population lives on the outer atolls. Yap is one of four member states of the Federated States of Micronesia, where, according to Perkins, satellite altimetry shows global climate change is forcing sea levels to rise faster than the global average: 5mm to 10mm per year compared with 3mm per year since 1993.

“The greatest cause for concern is when higher sea levels are combined with increased storm surges,” he said. “With a rise in sea level and storm intensity, these surges can make atolls uninhabitable and make near-shore land on high islands such as Yap unproductive. Those near-shore areas are some of Yap’s most productive for agriculture.”

The rising sea levels cause islanders living on coral atolls to relocate to the main island of Yap, he said. “Meanwhile, sea-level rise is also causing salinisation of near-shore agricultural lands. This means a decreased ability to grow food.”

The biggest challenge is “integrating food production with biodiversity protection. On a small island, it’s easy to see how everything is connected. The ridge leads directly to the reef. Terrestrial blends with the aquatic. So, whatever agricultural practice is developed on land will have a direct and immediate impact on the near-shore environment.”

In their project – funded by a three-year, US$150,000 grant from the US Forest Service – Perkins and Yapese scientific colleagues are trying to find suitable places to relocate the agricultural areas with the help of geospatial analysis (GPS, remote sensing) and geographic information systems. Perkins said basically that GPS tells you where you are, while GIS takes the where and adds the “what” and other information.

“In other words, GIS is a computer-based approach to managing spatial data by combining information about location with a description of that location. Every part of a landscape, say, the soils, streams, roads, plants, can all be stored as separate layers (imagine an infinite stack of clear transparencies on an overhead projector). In addition to knowing that a place recently burned, you could add information about how intense the fire was, what caused it, how it’s recovering.”

This helps anticipate possible future scenarios, Perkins said. “As sea levels rise, Yap needs to anticipate the changes that will occur. Using GPS, we can map precisely where agricultural areas are to combat the problem of dwindling food supply. Using GIS, we can analyse how much land will be degraded if the sea level rises. And, we can analyse what other areas upslope are best-suited for conversion to agricultural production based on the soils, slope and existing vegetation.”

Locally grown taro, a starchy vegetable, is a key consideration. Perkins cites the importance of another technological advance in the process: “What really makes the geospatial analysis sing is the inclusion of satellite imagery into the analysis. During this last trip, my students, Yapese counterparts and I mapped the location of several taro beds. Because taro reflects a particular collection of light wavelengths – it has a unique ‘spectral signature’ – we can use the satellite imagery to analyse every pixel on Yap for a similar signature. Then, we can estimate the total amount of area being used for taro production in low elevation areas.”

The Yap project transcends the preservation of a food supply. Because of the natives’ traditional emphasis on growing their own crops, it’s also about maintaining a way of life. “Every family owns a garden and a part of the reef,” Perkins said. “These gardens and reef areas are passed down from generation to generation. Each piece of land has a name and a history. In fact, when babies are born, their names don’t come from family members. They come from the parcel of land to which they are connected. There is enormous responsibility on you to properly take care of your land, because it is a part of you.” – The Charlotte Observer/McClatchy Tribune Information Services

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