Rising sea levels: The time to act is now to protect Pacific island communities
Pragmatic and cost-effective solutions can address rising sea levels across the Pacific – if action is taken now.
Over the last 100 years, sea levels have risen 200-250mm globally. Satellite data over the past 30 years shows that after a slow start, the rate of sea level rise is accelerating.
The World Meteorological Organisation this year revealed that global sea levels rose about 15 mm between November 2014 and February 2016 as a result of El Niño, well above the post-1993 trend of 3 to 3.5mm per year, with new record highs in early 2016.
This may not seem like a major or immediate problem for many countries. But for many small low-lying atoll nations across the Pacific it is potentially catastrophic, says Calibre Consulting’s Senior Project Director, Peter Ollivier, whose thoughts are reinforced by colleague Dr Arthur Webb, one of the world’s pre-eminent coastal management researchers.
As Principal Fellow with the University of Wollongong, most recently working in Tonga on coastal management, vulnerability and climate change adaption projects, Dr Webb has more than two decades of research in this category under his belt.
“Sea level rise is an imminent threat to land masses, cultures and peoples across the Pacific,” he states. “Many countries in the Pacific have atoll communities that are very low-lying. A huge proportion of the population is immediately threatened.
“Even on islands with higher landforms, the majority of settlements and infrastructure are also located in low-lying near-shore zones similar to atolls. So there is an awful lot of vulnerability in these communities from tsunamis and storms, and now from sea level rise.
“It is worth remembering that sea levels naturally fluctuate, in some locations by up to half a metre a year. This band of peaks and troughs is lifting over time; the peaks are getting higher and higher, and there are more frequent instances when those peaks cause coastal flooding and damage.”
Breach before repair.
Dr Webb says that another problem is also becoming clear as the sea rises. “As land becomes more frequently inundated over time it can change from a freshwater ecosystem to a sea water system, with corresponding effects on the local population.
“If you look at traditional modes of living in the Pacific islands, they are coastal and depend on living reefs for fishing, island building and wave protection, as well as near-shore freshwater swamps which often lie just a few metres inland.
“Any small change in reef productivity or structure can affect important resources like fisheries, as well as island building processes. Any threat to inundate swamps with sea water can destroy their agricultural potential. If reefs become dysfunctional, their ability to sustain the islands and their communities also comes into question.”
This means, he says, that work needs to be done to understand the nature of the island landforms and processes so they can be properly protected. But time is running out to do so.
What underpins the challenges?
Finding, funding and applying the right - and cost-effective - engineering solutions to protect reefs, coastlines and communities is essential, says Peter Ollivier, who has worked with Dr Webb on a number of projects.
“Many atoll shores are dynamic – they are continually moving, depending on the wind and waves,” says Ollivier. “Sea walls should not be assumed as an ideal solution, as they are fixed in place and stop this movement, so they can disrupt the natural processes and can either initiate or accelerate erosion on other parts of the atoll.”
He says that although sea walls provide immediate protection against waves and erosion, which is often the reason they are built, they are unlikely to provide a sound long-term protection against sea level rise.
“Atolls are porous, so, as the sea rises, water will come up through the ground behind the sea walls to flood the atoll; or the waves will come over the top of the walls or destroy them, as often happens in tropical cyclones.
“We therefore have to think differently to apply the appropriate solution to each individual problem. The solutions that might commonly be developed in New Zealand and Australia for our own conditions may not be appropriate for low-lying porous atolls. Techniques need to be tailored to local conditions, cultures and budgets.
“Understanding the coastal and tidal dynamics of a place takes time: years, in some cases. But if you look at most of the aid that supports this work, it is undertaken on a project-by-project basis, and often on a short-term cycle of one to three years. The donor wants results, so in many cases they cannot spend enough time on the underlying science to ensure the right job.”
So, what’s being done?
One thing is for sure: a lot of money is being spent to try to address these challenges. Hundreds of millions of dollars. But is the money always being spent in the right ways?
“Funding is coming from all over the world,” says Dr Webb. “There are examples of land reclamation globally, with different objectives and reasons – including lengthening runways, creating space for population growth and reinforcing national boundaries. So the technology is there, but the challenge is applying this appropriately in the Pacific.
“A sustained, multidisciplinary approach is key to ensuring resources are targeted to the best outcomes. The approach and resources must be targeted correctly, and we must find a balance between what is technically feasible and what may work in the context of unique Pacific Island cultures and landforms. There are huge opportunities to direct money into pragmatic and efficient solutions that look to the long term, and there are examples where resources are being used on inappropriate approaches.
“People are beginning to realise that broad scale land reclamation is an option, but on a scale that’s far beyond the experience of the Pacific to date. Communities are understandably nervous about the environmental implications of creating sea defences and raising ground levels. But for low-lying communities, there’s no option - and time is running out.”
Tuvalu takes an award-winning approach to the problem
The New Zealand Government is providing up to $200 million for climate-related support in the Pacific, and is leading the way in promoting reclamation projects.
The first, successfully completed, project is a Ministry of Foreign Affairs & Trade NZ Aid-funded project undertaken by Calibre Consulting to fill the ‘borrow pits’ on Tuvalu’s main atoll, which won the Gold Award at the recent 2016 ACENZ Innovate NZ Awards of Excellence.
The pits were dug during World War II when US Army forces excavated material from the atoll to construct a runway and reclaim the lagoon shore. Over time the pits filled with rubbish and became a health hazard.
The $10 million remediation project has filled in the pits, increased the available land area of the atoll by 6% and improved the resilience of the island to storm surges and sea level rise by lifting the land levels higher than the original levels. Completed in September 2015, it also reduced health risks for the population and significantly improved the quality of life for residents, with anecdotal reports of an immediate reduction in mosquitoes and dengue fever.
Described by the ACENZ judges as “setting a benchmark for cost-effective climate change response in the Pacific”, the project has also led to significant improvements in waste management and a major impact on the wellbeing of the Tuvalu community.
Key learnings from Tuvalu
A positive lesson from the Tuvalu experience was that it was not as risky as people thought, says Ollivier. “Just because you’re dredging in a coral island doesn’t mean you’re destroying the environment. We’ve shown that by doing your homework, you can manage dredging operations and protect the environment.”
“Most importantly, this project has shown that well-managed dredging and reclamation projects are viable large-scale options for low-lying island nations to consider as interim solutions to combat climate change, increasing resilience against sea-level rise. The project has demonstrated that the Government decision-makers in these small countries have the ability to shape their own future. Reclamation is an idea that has therefore come of age in the Pacific.”
“This is a great example of the government feeling empowered to make a decision to change their country for the better - an excellent example we can use to encourage other leaders to follow suit.”
Challenges of filling borrow pits around houses without flooding
Right solution, right place, before funding
Ollivier adds that a key learning is to apply the right solution to the problem at hand - before a project gets funded.
“We need qualified teams with the right experience to do the job, and we need long-term plans, not short-term thinking centred on building sea walls. If all that people believe is that sea walls work along a coast, they won’t seek the right solution for each new challenge.
“There are ways to work with the natural processes to create natural beaches and landforms. When combined with reclamation, they can provide more cost-effective methods to protect coastlines and avoid erosion. In the Netherlands, engineers have created what they call a sand engine - by understanding what happens along the coastline, they have placed a pile of dredged sand in one place and the currents move the sand along the coast and restore the beaches.
“While not necessarily the right solution for all atolls, it is a type of solution that needs to be considered. In Kiribati for example, MFAT is considering a large reclamation; it should be possible to create a new beach along the edges of the reclamation that is much more in tune with nature, and at a fraction of the cost of sea walls.
“Long term it’s all about that: natural defences are a lot cheaper long-term than sea walls and hard edges, but they require a little more time and money upfront. But for low-lying atolls, that costs a lot less than moving populations from their homes into new countries if their land isn’t protected.”
Positive, pragmatic action is needed now
Ultimately, says Ollivier, the risk of doing nothing means that future generations will suffer.
“The biggest problem is that the people in countries like Tuvalu and Kiribati have few resources. They need help to deal with coastal management. By taking the example of Tuvalu, other nations can see that this work can be done carefully and managed well with minimal environmental impacts.
“The Tuvalu experience shows that island governments can take positive and effective, pragmatic action. We can help them to protect their islands, continue to train and support their own technical people to gain buy-in from their own ministries, and lobby international agencies.”
He says that here and now is the time to act. “Many low-lying Pacific countries could end up being uninhabitable within 30-50 years, and then the people will lose their culture and sovereign status, along with their land.
“There’s a desperate urgency to use resources available today to help these small island states. If we don’t, the sea will continue to rise and people will have to move. We can either help them plan for it and do something, or we can sit by and let it become an urgent situation which needs a drastic response. In my mind, a planned response is always better than an unplanned response.
“People depend on coastal environmental systems and infrastructure. They need to be protected – or, in the case of infrastructure - redesigned or moved. Failure to act now and start to tackle these issues could spell real disaster for these communities. Let’s act now to try and save a nation.”
Locals playing volleyball