Island states are at the forefront of climate change. Rising sea levels mean more coastal erosion, overtopping of defences and salinification of land. More frequent and devastating severe weather events are disrupting everyday life and acidification of the ocean is impacting on fishing. It is happening now, not in decades to come.
From atolls in the Pacific Ocean to the coast of Northern Ireland Lidar – light detection and ranging, is helping island nations to become more resilient and adapt to the effects of climate change. Data is critical in order to be able to accurately map and predict the impacts of rising global temperatures and protect traditions of the past for generations to come.
Climate change in the Pacific
Island states in the pacific such as Fiji, Tuvalu, Kiribati, Palau and the Marshall Islands are at the front line of global warming. Every possible effect from land loss to intense weather and coral bleaching events is happening right now. But it is easy to think that the effects of climate change are a bit like these islands – very far away.
Fiji for example sits deep in the Pacific Ocean 1,770km North of New Zealand. For listeners in the UK imagine the entire length of the country from Land’s End in Cornwall to John o’ Groats in Scotland, and back again. Tuvalu is another 1,180km north of Fiji. And Palau is another 5,000km away – closer to the Philippines than New Zealand. Meaning that they have developed as very unique, self-sufficient, and resilient places to live steeped in history and tradition, with a deep understanding of the natural environment.
Fiji resident, and environmental specialist for UNDP Pacific Office, Wini Nainoca explains that natural environment is changing in ways that her ancestors could not have foreseen.
“I come from a traditional fisher tribe, my family in the village hierarchy, we are the traditional fishermen,” she says explaining that preserving the traditions of the past means harnessing technology of the future.
Wini is also a marine scientist with a PhD in conservation, a former university lecturer and is currently acting head of the resilience and sustainable development team of the UNDP in the Pacific. “We have about 65 projects in our team, from formulation to implementation stage from various funders, some are bi-laterals directly from the countries and also include other big vertical funders for environmental protection, such as the Global Environment Facility, and the Green Climate Fund.”
These projects include using lidar to survey the island nation of Palau in order to create a baseline map that will allow the government to understand exactly how the island coastlines are changing under coastal erosion and climate change.
It is work that builds on an earlier study done for the islands of Tuvalu, which have allowed it to become the first Pacific Island nation to create a long term coastal adaption strategy, and we will find out all about this later.
But in looking to the future it is important to understand the past. says that fisher tribes were known as the stewards of the sea, respected by the land based warrior tribes. Each part of the island community knew what the other had to offer and would work together for their mutual benefit. Knowledge is passed down generation to generation and traditions endure. “For instance when we go and visit a warrior tribe, we take the fish, and we are not allowed to eat fish in front of them. And they bring us pigs, and root crops, and they are not allowed to eat pigs in front of us.”
Changing conditions
Sadly things are changing for ancestors of both fisher tribes and warrior tribes as the effects of climate change take their toll. “Sea level rise means the water has encroached into the village and some of my cousin’s houses. Some parts of it are underwater during high tide. So they have learned to survive, they build longer structures, you know, these stilts, are longer and once the tide goes away, it becomes drier again,” says Wini.
There are many other effects too from warmer waters and acidification reducing fish habitats resulting in unpredictable catch volumes. At the same time populations are rising and competition for fish is increasing. Weather patterns too are changing.
“Tropical small islands have particular vulnerabilities,” says Arthur Webb, chief technical advisor and a coastal adaption strategist at UNDP. Alongside that he is also a research fellow with the University of Wollongong in southern New South Wales specialising in smaller islands known as atolls. He was also the lead author for the Intergovernmental Panel on Climate Change report into the effect of climate change on small islands.
Being remote, the islands are exposed to oceanic tectonic disturbances but new pressures are having an impact. “Climate change brings a whole new suite of challenges in that changing weather patterns, tropical storms, more intense storms, the fact that so many of our shores are living reef mediated shores. So that means they’re reliant on living reefs to mediate wave energy to produce material for the shorelines. And we know that with climate change, not only is sea level rise, ongoing and accelerating, but we’ve also got these incredibly concerning impacts to coral reefs across the world.
Tipping the balance
Arthur’s real passion is around protecting the smallest and newest of islands, the atolls, which are most at risk from climate change thanks to their small land area and their tendency to be low lying. “They are very young, geologically speaking. They seem an idyllic place and they are in so many ways. But it doesn’t take much to tip the balance,” he says.
The balance is well and truly tipping, but in order to predict exactly how far and how long some of these island communities have left, more data is needed.
“Even though the Pacific has three of the globe’s four, atoll nations, we haven’t had any systematic effort to actually understand the relationship between sea level and these land masses. So you know, we dwell in this world of generalisations, we talk about the low lying islands, and that they will become stressed by sea level rise. Well, that’s just not good enough. You know, we absolutely have the technology to do a better job,” says Arthur.
Because for many people time is running out. Doing a better job means obtaining better quality data in order to inform island communities about areas at risk and use predictive modelling to determine where might be safe in the future. “Now, in order to set up modelling that’s meaningful, you need high quality baselines that you need to be able to understand the shape of reefs that the depth of the reef below sea level and the shape of the beach in the land so that you can actually transform that wave from the reef where it’s broken across reef flats, and then over the island and understand how storms impact because that’s the whole other side of inundation threat.”
Basically to create the baseline you need accurate survey data, and that is where Lidar comes in. “LIDAR is a technology that’s been around for about 20 years. It’s uses laser and measures distance. So we capture the time from the pulse of light leaves the sensor to when it hits a target, and then returns, says Paul Seaton is regional director for strategic sales and marketing for Fugro.
Fugro has a number of systems that it can use for Lidar surveys. “The system that we’ve been using in the Pacific is a larger system, it uses a much more powerful laser It was designed originally for hydrographic surveys. So when in clear areas of the Pacific water clarity is, is good, we can get up to 80 metres in depth.”
Interestingly Fugro have different technologies for measuring the bathymetry, which is the land profile beneath the sea, and the topography, the profile of land above water along the coast, all carried on the same plane so that it is collected simultaneously. The flights use two pieces of equipment: the high powered laser to give us the greater depth penetration in the marine areas. “Overland we’re using a topo-bathy LIDAR as smaller lighter system that fires the laser at greater frequency, but with a lower power. And that gives us a very high resolution data capture over those land areas,” says Paul.
First time data collection
Tuvalu is the first Pacific Island nation to have Fugro gather this data and develop a long term coastal adaptation strategy. “All of these islands are extremely small. All of these islands are very low lying. And all of them are extremely sensitive to just a myriad of different stresses brought on by climate change,” says Arthur.
The good news is that the impact of these stresses from cyclones to sea level rise, can now be modelled against an accurate representation of Tuvalu’s islands, meaning that they can start to predict the future based on different scenarios. “By the year 2100, we may have an extra 0.75 metres of water to deal with. How does that translate in terms of wave impacts during that one in 50 years Cyclone or a one in 100 year Cyclone?”
It is very complex work requiring a lot of resources. The new understanding from this modelling is leading to accurate and appropriate coastal adaptation strategies. Wini says that in some parts of the pacific islands, villages have been moved only to have to move again five years later. Moving a village is a huge undertaking not just from a logistical perspective but there is much complexity over land ownership and availability. What is more most of these islands don’t know which land will be safe to live on in the future. “You need the baseline data and the adequate assessment to see whether or not that’s the case. Are their soils adequate for agriculture in this new location? Is it steep and subject to slumping? Is it barely any higher in elevation than the land they’ve just moved from and so will become subject to inundation very soon?”
There are so many considerations. It’s not simple. In Tuvalu having baseline data enabled them to identify a new area that will provide safe land for decades into the future. “It is indeed reclamation on the lagoon coast,” says Arthur explaining the plans for the capital Funfuti. “It’s informed by our new baseline and the wave modelling mentioned earlier. And it will provide roughly 7.5 hectares of raised safe land, which has a design horizon up to the year 2100, under current emissions scenarios.”
Planning for Palau
The Pacific Island nation of Palau has become the next to implement this type of surveying thanks to funding from the Japanese government. It is one of the 65 projects that Wini mentioned earlier. “When I saw the first few LIDAR images from Tuvalu, I saw that it captured the crayfish in the water. You know, like, I was so amazed,” says Wini.
Paul from Fugro explains that the survey itself was done in about 16 flights. “We didn’t cover all the islands, just the major ones,” he says. Palau has hundreds of islands. The exact number varies depending on the source but Wini says that there are around 500. “The data was captured in a relatively small period of time. So each flight can capture 30 to 40 square kilometres of data over survey area, depending on how far we’re transiting and the location of the airport. But we’re flying about 1,600 metres. And it’s a very efficient way to capture very valuable information,” says Paul.
Once the data is captured it has to be processed. For about every hour of flying, there’s about four hours of processing after that and then it is handed over to clients. “It’s not just handing over the data, it’s making sure that everybody understands it and can use it and know how to extract from the data, what they need to make the contribution that it will make,” says Paul.
The findings were important. “It really came out that a lot of our coastal villages, you know, it shows how dangerous they are living close to the sea. And it shows the vegetation, you know, where they could move inland. And it showed the width, you know, of the beaches and, and it’s just so amazing.
Wini now hopes that the Palau government will use it in the same way that Tuvalu has, to develop long term coastal adaptation strategies.
Lessons for Northern Ireland
Twelve thousand miles away, on the other side of the world, there is another island seeking to make informed decisions. “We’re very much now at a point in Northern Ireland, where we need to have a greater understanding of how our coastline is changing. And we need to identify how best we can manage it in a sustainable way,” this is Dr Joanne Hanna, a coastal geomorphologist within the Department of Agriculture, Environment and Rural Affairs. “We need to know the areas which are going to be most impacted by sea level rise, and areas where storms are likely to cause the most harm so that we can be better prepared,” she says.
Northern Ireland’s magnificent coastline stretches for 763km from Lock Foyle in Londonderry in the north down to Warrenpoint in the south. It’s one of the most variable and scenic coastlines in the world with significant geological diversity ranging from dramatic cliffs and long, sandy beaches. This presents a range of challenges to manage from rocky headlands and cliffs and which are interspersed with sand and gravel. To soft sedimentary coastlines, which are mobile and dynamic and which would be most responsive to environmental conditions and human impacts.
Over centuries and in modern times developments have sprung up all along the coastline and Northern Ireland’s strategy has been to build hard engineering to defend the line. But climate change and costal erosion means that this strategy is becoming untenable. “Over the years, the traditional response has been to build hard sea defences to protect the developments. And it’s estimated that 32% of our coastline is armoured,” says Joanne.
Within that 25% of sandy beaches are backed by sea defences, which themselves affect the coastal dynamics. Hard engineered structures, aimed at holding the line have had negative impacts on the coastal environment as coastal processes and sediment dynamics have been altered and the natural buffering effect which soft sediment systems provide has sometimes been lost. At the same time, just as we saw in the Pacific Islands, climate change is leading to warmer temperatures and higher sea levels. This is resulting in coastal flooding, and an increase in the rate and the extent of coastal erosion.
A new approach
Northern Ireland is aware that a new approach is needed and that this should be underpinned by better data. To fill this evidence gap Daera, Northern Ireland’s Department of Agriculture, Environment and Rural Affairs commissioned the Northern Ireland three dimensional coastal survey. “It is a high resolution survey providing an accurate picture of the current morphology of the coast on the near shore environment,” says Joanne.
To build up this morphological picture, we selected various methodologies. “A topographic LIDAR survey and was what we felt was needed which will extend from the intertidal area to approximately 200 metres inland. And then the for the near shore environment we acquired satellite derived with bathymetry data from the intertidal area it a mapping depth of approximately 10 metres. And then as a pilot project, we trialled the use of bathymetric LIDAR, which is not a methodology, which has been used widely in this part of the world before.”
Of particular importance was the requirement for data for what Joanne calls “the dead zone”. This is the area where marine vessels can’t reach because of shallow water depths, but also where terrestrial systems don’t extend down to also sometimes known as the white ribbon area
The white ribbon area, or the dead zone where much of the coastal action happens but data is hard to gather. Fugro conducted the surveys using their rapid airborne multibeam mapping system, and they know this area well. “There is a bit of a myth out there that areas is just too difficult to capture. But the LIDAR technology has changed that and so we’re able now to capture a single data set that overlaps those areas,” says Paul.
Joanne says that this survey will provide the baseline that Northern Ireland needs. “And then once complete, we will be able to build in this evidence base, and hopefully have repeat LIDAR surveys every three to five years. And then we’ll have a much, much better understanding of how our coastline is changing.”
Coastal and island communities whether in the Pacific Islands, Europe or anywhere in the world, are at the very forefront of climate change. Impacts are happening now and destroying lives and livelihoods. To create appropriate and successful adaption strategies more information is needed about how land is changing so that it can be combined with other data about wave effects, weather patterns and land use to create accurate models giving a clearer idea about future impacts.
Partner: Fugro
