Category: sea level rise

Sea level rise: three visions of a future summer holiday at the coast

Sea level rise: three visions of a future summer holiday at the coast

By Nick Davies and David Jarratt

The COVID-19 pandemic will ensure summer 2020 is a washout for most. With international travel restrictions limiting holidays abroad, many people in the UK have opted to stay somewhere closer to home. As a result, there have been remarkable increases in the number of visitors to beaches across the UK. Thousands flocked to a beach in Bournemouth on a single day in June, causing the local council to declare a major incident.

But far greater disruptions to our summer holidays lie ahead. About half of all tourism takes place in coastal areas, but with global warming set to raise sea levels by somewhere around two metres over the next 80 years, how will our relationship with the coast change?

Will we commemorate the old coastal boundaries with forlorn sojourns above the sunken land? Will we recreate the beach in the heart of our cities? Or will we preserve the drowned coast as a nature reserve – a quiet memorial to what was lost?

We imagined three different versions of what a beach holiday might look like as climate change eclipses the coastline we once knew.

1. Floating in place

Sea level rise may seem a distant threat, but resorts and other tourism operators are already considering how they can stay near the coast and operate above the water. On the Caribbean island of Barbuda, resort huts have been built on stilts.

The aim is to keep tourism viable in the same place it has thrived for decades, while minimising damage from higher water levels.

Seasteading is one answer to this conundrum. The idea to build settlements on platforms at sea originated with the hope of creating more sustainable and equal societies away from land. The technology is still being developed, while researchers consider the engineering, legal and business implications.

New research suggests that coastal flooding could threaten up to 20% of global GDP by 2100, with much of it tied to the tourism industry. Tourism could instead become a new source of income for seasteads. Given the dwindling coastal space for tourists, creating new spaces out at sea might be a way to meet the problem of sea level rise head on.

A cabin raised several feet above the sea water on stilts.
Heavy engineering could keep some resorts afloat. Serge Skiba/Shutterstock

2. Bringing the beach to you

The urban beach is a concept that’s growing in popularity worldwide. It involves creating sandy areas in towns and cities by importing sand onto concrete. There may also be artificial pools and fairground rides. Each one has different features. There are family-friendly options, and those catered to adults, with cocktail bars or restaurants.

The opportunities for hedonism are still there, but instead of travelling miles to enjoy it, it’s right on your doorstep. Less travel means less carbon emissions, and urban beaches might help ease pressure on the real coast.

Perhaps the most famous urban beach is the Paris Plage. Since its opening in 2002, Parisians and summer tourists have been able to lounge under palm trees on the banks of the river Seine. It cost over two million Euros to create and has since been extended due to its popularity.

The Paris Plage – a sandy beach with potted palms overlooking the River Seine.
‘Sous les pavés, la plage!’ Efired/Shutterstock

The Nottingham Riviera is an attempt to recreate this success in the UK. The landlocked beach in the middle of the city has sand and water, amusement arcades and beach bars.

The urban beach is becoming an industry in itself, with companies specialising in fake beaches that can be built as seasonal fixtures or permanent areas. If reaching the coast becomes too arduous in the future, these examples could provide everything needed for a seaside experience without the sea.

3. Rewilding the coast

Perhaps the most pragmatic solution is to accept nature taking its course and relinquish control as rising seas reshape the terrain. Allowing the new coastline to rewild could create millions of acres of new wetlands – habitats that are very good at storing carbon and that have deteriorated by about 50% since 1900.

Examples from Hong Kong, Spain, and Wallasea Island in the UK demonstrate how turning heavily managed coastal areas into new habitats can create new opportunities for wildlife and people.

So does the Mexican island, Mayakoba. Its unique mangrove forests were damaged and polluted by the building of numerous hotel chains on the seafront, but today, only 10% of these hotels rem ain on the coast.

The local community abandoned their high-density model of tourism and protected the dunes and mangroves, which were being eroded by excessive development. New canal networks were dug to create an estuary, attracting birds and amphibians. This new wetland was designated as a nature reserve and visitors arrived to enjoy a new kind of tourist experience.

A floating jetty surrounding by mangrove swamp.
Rewilding the coast would provide new wetland habitat for threatened species. Lara Danielle/FlickrCC BY

Visitor capacity and beach activities were reduced to ensure sensitive coastal environments could remain protected. But allowing the sea back into reclaimed coastal territory allowed a more sustainable model of tourism to flourish – one which could be replicated elsewhere as sea levels rise.

But before that can happen, our views of the coast must change. Humans once saw land and sea as a continuation of one another, rather than two discrete entities. Reviving this concept could allow us to navigate a future in which once certain borders have blurred beyond recognition.


This article was originally posted on The Conversation.
Cover photo by Sven Scheuermeier on Unsplash.
Rising tides will leave no choice for US millions

Rising tides will leave no choice for US millions

By Tim Radford

The Texan city of Houston is about to grow in unexpected ways, thanks to the rising tides. So will Dallas. Real estate agents in Atlanta, Georgia; Denver, Colorado; and Las Vegas, Nevada could expect to do roaring business.

The inland counties around Los Angeles, and close to New Orleans in Louisiana, will suddenly get a little more crowded. And from Boston in the north-east to the tip of Florida, Americans will be on the move.

That is because an estimated 13 million US citizens could some time in this century become climate refugees, driven from their seaside homes by sea level rise of possibly 1.8 metres, according to new research.

And they will have to move home in a poorer economic climate: worldwide. If governments and city authorities do not take the right steps, sea level rise could erode 4% of the global annual economy, says a separate study. That is, coast-dwellers could witness not just their towns and even cities washed away: they could see their prosperity go under as well.

Californian scientists report in the Public Library of Science journal PLOS One that they used machine learning techniques – in effect, artificial intelligence systems – to calculate what is most likely to happen as US citizens desert Delaware Bay, slip away from the cities of North and South Carolina, and flee Florida in the face of rising sea levels, coastal flooding and increasingly catastrophic windstorms.

“Sea level rise will affect every county in the United States … everybody should care about sea level rise, whether they live on the coast or not”

In the year 2000, a third of all the planet’s urban land was in a zone vulnerable to flood. By 2040, this could rise to 40%. In 2010, in the US, more than 120m citizens – that is nearly 40% of the entire population – lived in coastal counties. By 2020, this proportion could already be higher.

And by 2100, at least 13.1m people could be living on land likely to be inundated if sea levels rise by 1.8 metres. Except that they won’t: they will have already seen the future and moved away from it, to some settlement well away from the rising tides.

Those who might otherwise have purchased their abandoned seaside houses will be looking for somewhere safer and adding to the pressure on the housing market.

“Sea level rise will affect every county in the United States,” said Bistra Dilkina of the University of Southern California at Irvine, a computer scientist who worked with engineers to model the human response to the future.

She and her colleagues started from patterns of movement that began with Hurricane Katrina, in 2004, and Hurricane Rita a year later, both in Louisiana. They then let the algorithms take over the challenge of guessing what American families and businesses are most likely to do as the tides begin to flood the high streets.

Action promised

“We hope this research will empower urban planners and local decision-makers to prepare to accept populations displaced by sea level rise. Our findings indicate that everybody should care about sea level rise, whether they live on the coast or not,” she said.

The California team’s worst-case forecasts are based on a premise that the world takes no real action to combat sea level rise, which is driven by global warming powered in turn by fossil fuel emissions into the atmosphere on an ever-increasing scale.

But in Paris in 2015, more than 190 nations did agree to act: to contain global warming to “well below” 2°C by the century’s end. So far, very few have committed to sufficient action, and the President of the US has pronounced climate change a “hoax” and announced a withdrawal from the Paris Agreement.

Researchers in Austria report in the journal Environmental Research Communications that they decided to consider the potential economic cost worldwide of sea level rise alone. Scientists have been trying for years to guess the cost of flood damage to come: the latest study is of the impact of sea level rise and coastal flooding upon national economies worldwide.

The scientists considered two scenarios, including one in which the world kept the promises made in Paris, and one in which it did not, and made no attempt to adapt to or mitigate climate change.

Significant impact

By 2050 losses in each scenario would be significant and much the same. But by 2100, the do-nothing option promised to hit the gross domestic product – an economist’s favourite measure of economic well-being – by 4%.

Europe and Japan would be significantly hit; China , India and Canada hardest of all. If the world’s richest nations actually worked to limit climate change and adapt to the challenges ahead, the impact on the economy could be limited to 1%.

“The findings of this paper demonstrate that we need to think long term while acting swiftly,” said Thomas Schinko of the International Institute for Applied Systems Analysis in Austria, who led the study.

“Macroeconomic impacts up to and beyond 2050 as a result of coastal flooding due to sea level rise – not taking into account any other climate-related impacts such as drought – are severe and increasing.

“We, as a global society, need to further co-ordinate mitigation, adaptation and climate-resilient development and consider where we build cities and situate important infrastructure.”


This article was originally posted on the Climate News Network.
Cover photo of Houston, Texas by Vlad Busuioc on Unsplash
Ancient Antarctic ice melt caused extreme sea level rise 129,000 years ago – and it could happen again

Ancient Antarctic ice melt caused extreme sea level rise 129,000 years ago – and it could happen again

By Chris Fogwill, Chris Turney and Zoe Thomas

Rising global temperatures and warming ocean waters are causing one of the world’s coldest places to melt. While we know that human activity is causing climate change and driving rapid changes in Antarctica, the potential impacts that a warmer world would have on this region remain uncertain. Our new research might be able to provide some insight into what effect a warmer world would have in Antarctica, by looking at what happened more than 129,000 years ago.

We found that the mass melting of the West Antarctic Ice Sheet was a major cause of high sea levels during a period known as the Last Interglacial (129,000-116,000 years ago). The extreme ice loss caused more than three metres of average global sea level rise – and worryingly, it took less than 2˚C of ocean warming for it to occur.

To conduct our research, we travelled to an area on the West Antarctic Ice Sheet and drilled into so-called blue ice areas to reconstruct the glacial history of this ice sheet.

Blue ice areas are areas of ancient ice which have been brought to the surface by fierce, high-density winds, called katabatic winds. When these winds blow over mountains, they remove the top layer of snow and erode the exposed ice. As the ice is removed by the wind, ancient ice is brought to the surface, which offers insight into the ice sheet’s history.

While most Antarctic researchers drill deep into the ice to extract their samples, we were able to use a technique called horizontal ice core analysis. As you travel closer to the mountains of the ice sheet, the ice that been brought to the surface by these winds progressively gets older. We then were able to take surface samples on a straight, horizontal line across the blue ice area to reconstruct what happened to the ice sheet in the past.

Drilling into blue ice. Professor Chris Turney, Author provided

Our team took many measurements. We first looked at the fine layers of volcanic ash in the ice to pinpoint when the mass melting took place. Alarmingly, the results showed that most ice loss happened at the start of Last Interglacial warming, some 129,000 years ago – showing how sensitive the Antarctic is to higher temperatures. We think it’s likely this melting started well before the ocean warmed by 2˚C. This is concerning to us today, as ocean temperatures continue to increase, and the West Antarctic is already melting.

We also measured temperature-sensitive water molecules across the blue ice area. These isotopes revealed a large shift in temperatures, highlighting a major gap in our record at the start of the Last Interglacial. This indicates a period of sustained ice loss over thousands of years.

This period of missing ice coincides with extreme sea level rise, suggesting rapid ice melt from the West Antarctic Ice Sheet. DNA testing of ancient microbes preserved in the ice revealed an abundance of methane-consuming bacteria. Their presence suggests that the release of methane gases from sediments under the ice sheet may have also played a role in accelerating the warming process.

The West Antarctic ice sheet can tell us a lot about the effect of warming ocean temperatures because it rests on the seabed. It’s surrounded by large areas of floating ice, called ice shelves, that protect the central part of the sheet. As warmer ocean water travels into cavities beneath the ice shelves, ice melts from below, thinning the shelves and making the central sheet highly vulnerable to warming ocean temperatures. This process is currently being researched on the West Antarctic Thwaites Glacier, nicknamed the “Doomsday Glacier”.

Using data from our fieldwork, we ran model simulations to investigate how warming might affect the floating ice shelves. These ice shelves protect the ice sheets and help slow the flow of ice off the continent. Our results suggest a 3.8 metre sea level rise during the first thousand years of a 2˚C warmer ocean. Most of the modelled sea level rise occurred after the loss of the ice shelves, which collapsed within the first two hundred years of higher temperatures.

These findings are worrying – especially if persistent high sea surface temperatures could prompt the larger East Antarctic Ice Sheet to melt, driving global sea levels even higher. But our findings suggest the West Antarctic Ice Sheet may be close to a tipping point. Only a small temperature increase could trigger abrupt ice sheet melt and a multi-metre rise in global sea levels.

At the moment, research suggests that global sea levels could rise between 45-82cm over the next century. However, it’s thought that Antarctica will only contribute around 5cm of this – most of this sea level rise will be caused by warmer ocean waters and the melting of the Greenland Ice Sheet. But based on our findings, Antarctica’s contribution could be much greater than anticipated.

Despite 197 countries committing under the Paris agreement to restricting global warming to 2˚C by the end of this century, our findings show that even minor increases in temperature could have far-reaching impacts.


This article was originally published on the Conversation.
Cover photo from pixabay.
Climate threat to tourism threatens economic stability of island nations

Climate threat to tourism threatens economic stability of island nations

By Will Bugler

The threat that climate change poses to the tourism industry threatens to collapse the economies of several island nations around the world. Those countries that are most dependent on tourist dollars to sustain their economies also have tourist industries that are highly vulnerable to climate change and its impacts. In 2017 there were 20 countries for which tourism contributed more than 25 percent of GDP, the overwhelming majority of which are small island developing states. Climate impacts such as extreme heat, sea level rise, extreme storms and ecosystem destruction, pose a severe risk to the sustainability of these industries.

For island nations such as the Maldives, Seychelles, Antigua and Barbuda and the Bahamas, the tourist industry contributed 76.6%, 65.3%, 51.8% and 47.8% of GDP respectively. The level of dependence on tourism for such countries makes them highly vulnerable to climate risks that threaten the industry. However, they are also highly exposed to just those risks.

The most significant driver of tourism for small island states are their coastlines. Tourists are drawn to the magnificent sandy beaches and marine ecosystems. However, sea level rise, ocean warming, and coastal erosion is likely to damage or destroy these assets entirely. Recent studies indicate that the world’s coral reef ecosystems could be gone by 2050 and a sea level rise of 1 m would submerge almost all of the world’s beaches. This is far from unlikely, a 2017 NOAA report offered the scenarios shown below, with sea level rise ranging from 0.3 m to 2.5 m by 2100.

The coloured bars on the right represent IPCC 90% probability. The dashed lines represent the projections of a more recent study by DeConto and Pollard. Source: Modified from Sweet, et al. 2017.

Such a rise would be devastating for coastal economies. The map below shows coastal areas in blue that would be submerged should sea levels rise by 1m.  

Areas in blue show land that would be submerged should sea levels rise by 1m (40 in). Source: http://globalfloodmap.org/

The extent to which it is possible for vulnerable nations to diversify their economies will determine, to some extent, how resilient they are able to become in the face of climate change. However, climate change poses an existential threat for many island nations. For instance, at current rates, sea levels could be high enough to make many island atolls uninhabitable by the end of the century.


Cover photo by Alessandro Caproni/Flickr (CC BY 2.0): Shipyard in the Maldives.
Far-sighted adaptation to rising seas is blocked by just fixing eroded beaches

Far-sighted adaptation to rising seas is blocked by just fixing eroded beaches

By Andrew G. Keeler, East Carolina University; Dylan McNamara, University of North Carolina Wilmington, and Jennifer Irish, Virginia Tech

Coastal communities around the world are struggling to adapt to rising sea levels and increasingly severe coastal storms. In the United States, local governments are making investments to reduce those risks, such as protecting shorelines with seawalls, “nourishing” eroded beaches by adding sand and rerouting or redesigning roads and bridges.

In the short run, spending public money this way is economically rational. But in the long run, many people who live near coastlines will probably have to relocate as seas continue to rise.

We have studied this problem by combining insights from our work in economics, coastal geomorphology and engineering. As we have explained elsewhere, short-term actions to adapt to coastal flooding can actually increase risks to lives and property. By raising the value of coastal properties, these steps encourage people to stay in place and delay decisions about more drastic solutions, such as moving inland.

Keeping millions in harm’s way

According to recent estimates, a 1-foot increase (0.3 metres) in sea levels will put about 1 million people in the United States at risk, and 3 feet (0.9 metres) will threaten about 4 million people. Global sea levels currently are projected to rise 0.5 to 2.1 feet (0.15-0.64 metres) by 2050 and 1.0 to 8.2 feet (0.3-2.5 metres) by 2100.

As we see it, market forces and public risk reduction policies interact in unexpected ways, reducing incentives for communities to make long-term plans for retreating from the shore. Nourishing beaches and building seawalls signal to individuals and businesses that their risks are lower. This makes them more likely to build long-lasting structures in risky areas and renovate and maintain existing structures. As a result, their property values increase, which reinforces economic and political arguments for more risk-reduction engineering.

To illustrate this pattern, we compared a sample of houses in Nags Head and Kitty Hawk, North Carolina, two popular beach towns less than 10 miles apart on North Carolina’s Outer Banks. When we consulted county tax appraisal values, Nags Head beaches had routinely received sand from beach nourishment, whereas Kitty Hawk beaches had not. On average, homes in our Nags Head sample were worth over US$1 million, while homes in the Kitty Hawk sample were worth about $200,000.

Other researchers have found that in some locations, the threat of rising seas is eroding coastal property values. But this tends to be true for properties that are viewed as highly vulnerable – for example, homes that have already flooded. In contrast, homes that are elevated or have other flood-proofing features tend to have much higher values, so they are perceived as assets.

Subsidizing risky choices

Some amount of risk reduction makes sense. If people who benefited paid its full cost, and everyone involved understood how imminent the risk was and how much engineering solutions would cost, then market forces would likely produce reasonably efficient solutions.

As an example, flood-prone Norfolk, Virginia recently adopted an ordinance requiring almost all new homes and many major renovations to be elevated and include other flood-proofing features. This approach will help to price flood protection into the cost of homes and will tend to reduce demands to directly subsidize protective engineering, flood insurance and post-disaster assistance.

In our view, such solutions are a move in the right direction. But they will not break the positive feedback loop we describe as long as other public policies continue to skew perceptions of the long-term viability of coastal communities.

Engineering projects to slow shoreline retreat and reduce flooding generally receive smaller subsidies now than in past decades, but many communities still benefit. For example, beach nourishment in Ocean City, Maryland is cost-shared between the federal government, which pays about half, and state and local agencies. The Federal Emergency Management Agency helps pay to rebuild homes and public buildings damaged in major disasters. And allowing people to deduct local taxes on their federal tax forms partly subsidizes local tax financing for risk reduction.

Beach nourishment started at New York’s Coney Island a century ago. But with the sheer volume of sand needed to keep up with sea level rise, its costs could outweigh its benefits within a few decades.</small

Inaccurate perceptions of risk

Information and uncertainty are larger problems. Many coastal residents do not perceive medium- and long-term climate risk to be as serious as the scientific consensus suggests. Moreover, scientists are still analyzing how fast sea levels are likely to rise. Future storm frequency is uncertain, and could be affected by changes in global greenhouse gas emission trends.

On the positive side, engineering innovations such as designing storm-resistant homes could become more effective. But existing approaches like beach nourishment are likely to become more expensive as sand resources diminish and more communities compete for them. And growing uncertainty is likely to increase near-term demand for risk reduction engineering.

The most critical time for adaptation decisions is immediately after a storm or flood. Faced with expensive repairs or rebuilding, property owners face higher costs to return to the status quo. But if homeowners expect that public resources will be spent to protect them against future disasters, they are less likely to consider making big changes.

Federal or state financial rebuilding assistance creates a similar bias. If that money were used to subsidize relocation or other drastic adaptive actions, rebuilding patterns would be different. So far, however, programs for buying out flood-damaged properties have been largely unsuccessful. Many factors, including residents’ level of experience with disaster recovery and financial concerns, can make people unwilling to consider relocating.

Incentives to think long-term

There is no perfect formula for balancing near-term climate-proofing against more drastic steps to move people away from the coasts. But we believe that when communities focus excessively on reducing near-term threats, they risk inhibiting the successful adaptation that they are trying to promote.

We have three suggestions for breaking this cycle. First, local land use policies could be designed to discourage rebuilding homes to similar or higher property values after damage from storms. Second, communities could put increasing emphasis on adaptive engineering and large-scale planning practices – for example, sunsetting beach nourishment projects when sea level rise reaches some preannounced level.

Finally, adaptation decisions could be planned and implemented at a multi-jurisdictional level, rather than town by town. This approach would help to avoid “rich towns get richer” dynamics that can develop when wealthier jurisdictions deploy sand resources and other protective measures in a way that reduces their own risk while ignoring or heightening threats to nearby locations.

Change is coming to coasts around the world. We believe that broader understanding of how markets and public policy interact is essential to minimize the social and economic costs of this change.The Conversation


This article was originally published on The Conversation. Read the original article.

Cover photo by Ashley Satanosky on Unsplash.
Accelerating sea level rise triggered by Antarctic ice melt raises urgent adaptation concerns

Accelerating sea level rise triggered by Antarctic ice melt raises urgent adaptation concerns

By Elisa Jiménez Alonso

As was reported this week, satellites monitoring Antarctica indicated that roughly 200 billion tonnes of its ice are melting each year. The massive ice loss is accelerating sea level rise by about 0.6 millimetres per year – three times more than measured during the last assessment in 2012.

Overall, since 1992 the continent has lost 3 trillion tonnes of ice, enough to raise global seas by 8 millimetres. The researchers responsible for this new assessment say it is “too warm for Antarctica today. It’s about half a degree Celsius warmer than the continent can withstand and it’s melting about five metres of ice from its base each year, and that’s what’s triggering the sea-level contribution that we’re seeing.”

For low-lying coastal communities and cities, this rapid acceleration of sea level rise is troubling news as it is a harsh reminder of how little time there is to prepare for such a daunting challenge. The impacts of sea level rise are manifold, it can lead to coastal erosion, makes storms more dangerous because storm surges lead to flooding more quickly, king tides can flood communities, and for low lying island states it could even mean the loss of their land.

Meaningful and large-scale climate change mitigation could help avoid worst case scenarios. But, with the uncertainty surrounding such actions and the scale at which we could see it implemented in the next years, building resilience to the impacts of sea level rise will be paramount, or rather is already.


Cover photo by Cassie Matias on Unsplash.