New Zealand’s first climate adaptation plan includes most of the climate-resilient options you would expect to find. Nature-based and hard-engineering solutions, such as wetlands and sea walls, feature prominently. As do upgrades to properties and infrastructure to withstand more extreme weather conditions, and initiatives to better educate and prepare communities to the perils of climate change.
But it is chapter five in the 196-page document that got most media attention when it was unveiled in August 2022. It is entitled “Adaptation options,” but what made it newsworthy is that the rest of the title reads: “including managed retreat.”
Managed retreat involves the strategic relocation of people, buildings and other assets from areas vulnerable to climate change and natural hazards. It is not a new concept, but New Zealand’s announcement has certainly put it back in the spotlight.
The phrase “managed retreat” was used by coastal engineers in the early 1990s as a response to sea level rise in Essex, UK. It has since been viewed as a solution to global sea level rise that could impact up to 410 million people by 2100. For instance, the low-lying Pacific island nation of Kiribati bought land in Fiji in 2014 to allow a future migration if rising sea levels make their islands uninhabitable.
In some cases, managed retreat includes mechanisms such as “setbacks” that either require new development to be a minimum distance from the shore or restricted in density. But the concept of relocating whole communities is gaining credence.
Michael Szönyi, Head of Zurich Insurance Group’s Flood Resilience Program, believes managed retreat is a viable option. “In the past there was a long tradition of abandonment or managed retreat due to environmental or economic changes, such as drought or a loss of industry.
“But there may be a need to revive this tradition. It is not sustainable to build larger sea defences or levees along vast stretches of coasts or rivers. Other options will need to be considered. In some cases, managed retreat may even become a necessary response to the impacts of climate change in the decades ahead.”
Managed retreat is not only a potential answer to sea level rise. The village of Matatā in New Zealand pursued the managed retreat option due to flash flooding from nearby hills, while the town of Valmeyer, Illinois, relocated as it was being impacted by inland flooding caused by the Mississippi River (see box below). A 2017 study, which analyzed 27 cases of managed retreat in 22 countries, found that about 1.3 million people have been relocated through managed retreat over the past three decades in response to natural hazards, including tropical storms, erosion, earthquakes and tsunamis.
Examples of managed retreat
The coastal village of Matatā in New Zealand was engulfed in slurry, rocks and timber in a massive debris flow caused by flash floods coming down from the surrounding hills in May 2005. It destroyed 27 homes and damaged 87 other properties. The regional council was unable to find any viable engineering solutions or early warning systems that could mitigate the risk, so it opted to pursue a managed retreat in 2012.
In summer 1993, the farming community of Valmeyer, Illinois, was flooded twice in a month when the swollen Mississippi River topped its levee system. The floodwater lingered for months, damaging 90 percent of properties. Faced with rebuilding the town and risking further flooding, the 900 residents instead decided to use funding – including assistance from the Federal Emergency Management Agency (FEMA) – to rebuild an entire town “New Valmeyer” on higher ground a mile away.
Due to rising sea levels and threat of storm surge, the coastal village of Fairbourne in west Wales, UK, will need to adopt a policy of “managed realignment” between 2025 and 2055 – requiring the relocation of property owners and businesses (including 850 residents). The site will then be turned back into a tidal salt marsh. The villagers could be the UK’s first climate refugees “said The Guardian.”
The challenges of managed retreat
But people are not easily relocated from their homes. They build close attachments to their property, local culture and community, which can cause social and psychological difficulties – particularly if it involves loss of cultural heritage or moving a family from their ancestral lands. Even the term “managed retreat” to some people sounds like you are accepting defeat or giving up on a community – and that can be difficult to internalize.
Relocating communities also involves a huge financial cost. In New Zealand’s climate adaptation plan, it admits that “costs and benefits will need to be carefully weighed” in any considered managed retreat. Economic prospects can also be adversely impacted. For example, managed retreat might require fishing communities to move farther from the ocean. All these challenges – ethical, logistical, financial and legal – make it difficult for local and national governments to take decisions that could be considered controversial or politically perilous.
However, New Zealand’s Government is ensuring it will be prepared for these challenges. It plans to develop legislation through a new Climate Adaptation Act – delivered by the end of 2023 – to address these complex issues.
But it is one thing relocating a small town or village; another when you try to undertake a managed retreat from a megacity.
Jakarta is one of 570 coastal cities vulnerable to a sea level rise of just 0.5 meters by 2050. An issue compounded by severe land subsidence – caused mostly by excessive groundwater extraction – that is causing parts of the city to sink.
In 2019, the Indonesia government announced it would relocate its capital to the province of East Kalimantan on Borneo. It hopes to start relocating to the new city – called Nusantara – in 2024. Although it is not an official managed retreat, the relocation would help relieve pressure on Jakarta and potentially enable people in the worst affected areas on the coast to relocate.
“Even in a dire situation like that in Jakarta, you do not need to abandon the whole city. Some cities could undertake a partial managed retreat on some of its land on the coast to create a wetland area, such as mangroves. That would not only move people to safety living in those areas; it could also provide more natural flood spaces that can help the rest of the city’s population,” says Zurich’s Szönyi.
Better than a forced retreat
Despite some of the controversy that surrounds the concept of managed retreat, many communities are already in a forced retreat. According to the United Nations High Commissioner for Refugees (UNHCR), an annual average of 21.5 million people have been forcibly displaced by weather-related events – such as floods, storms, wildfires and extreme temperatures – since 2008. An estimated 1.2 billion people – often referred to as climate refugees – could be displaced globally by 2050 due to climate change and natural disasters.
The plight of climate refugees shows us that climate change does not only pose an immediate threat to people and property due to a destructive hurricane or wildfire. Climate change is also a long-term danger that can slowly destabilize societies and economies. It can reduce water availability and water quality, increase the spread of disease and raise the likelihood of drought leading to crop failures that may reduce incomes and cause hunger.
“The need to take conscious decisions about managed retreat will inch closer,” says Szönyi. “Climate change is already altering the size and direction of migration flows. Instead of people being forced into an unplanned retreat, strategically relocating people through managed retreat may be a better policy. Faced by climate change, our survival depends on changing our ways of life, including where we live.”
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