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Recent media speculation has led us to believe that in a few hundred years some cities may start to see the effects of global warming and rising sea levels. However, new scientific findings suggest that this future will be much sooner then we initially thought. This article sheds light on 25 at risk coastal cities and developing islands around the world.

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Click on a circle to see what city, country, and population it represents. The colour and size of each circle will represent the amount of risk that city is in relevant to the sea level scroll bar. Choose a level or press the play button to see the change over time.

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Note* this article is intended to be purely informal and should not be used as a scientific paper. Data and predicitons are based on finding averages and generalisations and therefore are not concrete evidence of what will happen, but instead what could happen.

Picture that perfect getaway island, that one you dream of when you’re stuck behind the desk and the boss is breathing down your neck. You want to turn around and tell him the two words every man and women working 9 to 5 in an office has ever dreamt of saying; “I quit”. However, you can’t because you know you need that job to earn that money that pays for that airfare that gets you to that magical utopian paradise that you always dreamt of. Well, that dream may well remain a dream with the threat of global warming and rising sea levels. According to a recent report by ‘The Intergovernmental Panel on Climate Change’ (IPCC), the last century has seen the Global Mean Sea Level (GMSL) increase by an annual average of 1.7 millimetres. However, in the last 17 years from 1993 to 2010, this rate has increased to 3.2 millimetres a year. This is an increase of almost 200% in just a 20-year period. Whilst this escalation is quite staggering, the most alarming findings come from scientists who predict that by 2100 GMSL could rise by one meter. This would average out to be 10.5 mm a year, an increase of 300% from the last 20 years. This will have devastating effects on low lying cities such as Miami and Venice. Furthermore, lowly elevated islands, especially those in the South-Pacific, have already witnessed these impacts and thousands of people have had their homes damaged and forced to migrate to places such as the US.

What causes GMSL rise

The causes of rising GMSL are derived from two sources; thermal expansion, and the melting of earths ice reserves.

Thermal Expansion – comes from the theory of thermodynamics in which it states; matter changes in shape, area, and volume as result of temperature change. As a substance is heated, the kinetic energy of its molecules increases. To put it simply, as the earth and the sea becomes warmer, it assumes a greater mass. Almost a third of contributing factors for the predictive GMSL rise is contributed by thermal expansion.

Melting of Earths Ice Reserves – ice caps represent 68.7% of all freshwater on earth. Therefore, if they were to melt it would have devastating effects on civilisation and entire marine eco-systems would be damaged. If all glaciers were to melt today, the GMSL would rise by 70 meters(NSIDC). This would be enough to flood thousands of cities and leave millions of people homeless. Fortunately, ice caps have only seen partial loss. However, when you take in to consideration the astonishing mass of these ice reserves, the tiniest fraction would constitute massive impacts on the GMSL. The IPCC’s ‘Fifth Assessment Report’ found that the Antarctic Ice Sheet alone accounted for 0.41mm of the annual GMSL rise. The report also found that this huge amount of ice loss has likely increased from about 30Gt (1 gigatonne = 1 billion tonnes) per year between 1992 to 2001 to approximately 147Gt per year between the years 2002 and 2011, an increase of 490%. In Greenland, the rate of ice shafting is even worse. For the same period, Greenland’s rate of ice loss has increased by 630% from 34 Gt per year to a staggering 215 Gt’s a year. The melting of these ice reserves and other glaciers accounts for over a third of GMSL rise.

Cities at Most Risk

Based on the numerous government reports, scientific findings, core samples, tide gauge readings, and satellite measurements it is highly evident that a strong correlation between climate change and GMSL rise exists. But what affect does this have on the planet and who is at most risk. We have compiled data on over 25 coastal cities, combining a total population of over 180 million people and spanning 17 countries to analyse those most at risk. To calculate the level of risk for each city, we averaged the annual GMSL rise based on the IPCC’s predictions and compared this data with each cities average elevation. At the top of the list, with minimal surprise was Venice, Italy. Venice has a mere average elevation of only 1 meter above sea level. Many Scientists have warned about the potential ‘disappearing’ of one of the most historic coastal cities in the world. Venice is home to many important historic events including the Renaissance and Symphonic Opera music. If Venice was to become submerged, an entire part of civilisations history would go with it. Venice is also home to over two and a half million people, which if these predictions are true, would mean that over two million people could be homeless by the year 2100. This will ultimately lead to a number of issues as a result of the forced migration from these coastal areas to mainland cities of Italy. However, if you thought that was bad imagine not having a ‘mainland’ to escape to when your home becomes submerged by rising sea levels. That is the exact and disheartening fate for the thousands of people who call the south pacific islands, such as Tuvalu home. A number of lowly elevated islands, especially those in the South Pacific region face a daunting future if sea levels rise at the predicted rate. Tuvalu, a small group of islands consisting of five coral atolls and four reef islands, is one of these areas. Tuvalu lies in the Oceania about halfway between Australia and Hawaii and has a total population of roughly 10, 000 people. Tuvalu has an average elevation of 2 Meters and its highest point is only 4.6 meters. This makes it one of the most at risk areas of rising sea levels in the world. Tuvalu has already seen the impacts of global warming with high tides, tropical storms and trade winds destroying many homes and crops. However, if global warming and GMSL rises continue at the expected rate these issues will become much more destructive and frequent. Based on our findings, Tuvalu will see drastic impacts over the next 100 years and continue to do so until the area is completely submerged.

Two and a half thousand kilometres north of Tuvalu lies Marshall Islands, a country with a very similar catastrophic fate. Marshall Islands has an average elevation of 2 metres and a total population of over 50, 000 people. Like Tuvalu, the Marshall Islands are already facing the impacts of GMSL rise and climate change. Many homes have been damaged and property repeatedly repaired. The threat of GMSL rise is so worrying that over one third of its population have migrated to the United States. Now, it would be inaccurate to say that this is the sole reason why so many people have left. However, the Marshallese president Hilda Heine, believes this to have a profound impact on these migration patterns. “I think to a certain extent there are people who are thinking about the sea level rise and they’re wanting to make sure they’re on secure land.”.

To the east of Tuvalu and the Marshall Islands lies yet another region of atolls at high risk of climate change. Kiribati consists of 33 atolls and reef islands with a population of over 100, 000. The last large tidal surge was so bad that it smashed through the doors and windows of a hospital, leaving behind sand and debris. Local handyman, Beero Hosea, believes the fate and rise of sea levels is all to real, “If the next one is combined with a storm and stronger winds, that’s the end of us. It’s going to cover this whole island”. All of the evidence points to the demise of these areas and the thousands of other islands like them. But why don’t we just re-locate them to other areas and other countries? We as a global collective have enough land and enough resources to cater for these few hundred thousand people who call these islands home. Besides the enormous amounts of money to relocate these people, the strenuous pressure it would place on many countries infrastructure and resources, and the numerous socio-political issues that it would invoke. These people will be losing their homes, livelihoods, and perhaps most importantly, their history and culture. The majority of these inhabitants have called these islands home for hundreds of years. These islands are rich with culture and history, forced migration of these people would mean losing a part of their history. These small developing nations may well be the most at risk, however, other very large cities could also face a similar fate, albeit a further future away. Miami, USA has an astonishingly low average elevation of only 1.8 metres. The coastal city, home to over 400, 000 people, has already seen the affects of a changing climate which scientists warn could have a very grim future. Miami has experienced some of its worst floods in recent years that has cost millions of dollars in damage. A recent report put Florida as the state with the most property at risk of climate change in the whole of the US. One report claimed that if sea levels rise by just half a meter by 2070, $3.5 trillion in assets would be at risk. Furthermore, Miami is not alone with mega cities like Bangkok, Shanghai, Lagos, and Dhaka facing a similar future. All four of these cities have a combined population of almost 60, 000, 000 people and are set to see the impacts of GMSL rise in the fore coming years. These cities may not be impacted for another 100 years and the vast majority of you reading this article will never see your house submerged or your favourite holiday destination vanished. But what about your children, and their children’s children? Do you really want to leave behind a planet that has lost so much of its beautiful natural habitat and rich history and culture? As sir David Attenborough says; “The truth is: the natural world is changing. And we are totally dependent on that world. It provides our food, water and air. It is the most precious thing we have and we need to defend it.”.



The Solution

Unfortunately, it is essentially impossible to stop GMSL rise altogether. By cutting emissions, the rate at which the sea level rises could well be reduced but would still reach devastating heights by 2100. A recent study by the National Center on Atmospheric Research (NCAR) concluded that if drastic cuts to emissions were made, then the 2100 predictions of a 1 meter GMSL rise could be reduced by 15cm to 50cm. However, that would still mean a huge rise in the GMSL and many of the aforementioned cities and islands would still be impacted. One of the core predicaments with reducing GMSL rise is that it’s a lot easier to alleviate global temperatures then it is to reduce GMSL rise. This is due to the carbon-dioxide that has already been released in the atmosphere which will stay atmospheric and likely impact the oceans for thousands of years. The study also finds that if emissions continue then the planet could see a 4℃ increase by 2100. There is much speculation over how much we could decrease this prediction amount by. In the most profligate statements where drastic global reductions in carbon emissions are completely stopped, we could see an increase of 0.6℃. However, this is essentially an impossible measurement and as stated earlier would still result in an alarming GMSL. The problem is, even if we were able to slow down the rate of GMSL rise then it would buy time for the ‘at-risk’ cities, but add on a few more centuries and these places are still going to be submerged and millions of people left homeless. Furthermore, despite advancements in renewable energy and the adoption of these practices by progressive countries such as Sweden and Norway, carbon emissions are on the rise. The United States Environmental Protection Agency (EPA) data The United States Environmental Protection Agency (EPA) data shows a huge increase in Global Carbon Emissions from fossil fuels. Since 1970, CO₂ emissions have increased by a staggering 90%, with emissions from fossil fuel combustion and industrial processes contributing about 78% of the total greenhouse gas emissions increase from 1970 to 2011. In conclusion, the Global Mean Sea Level is going to rise and millions of homes will be lost. However, if we can make drastic changes to the amount of carbon emissions as a global collective then we can hinder the rate at which this process occurs. This will leave us with more time to strategise further options and possibly create new solutions. This choice is ours, and the rate at which these things happen is up to us. So ask yourself; do you want to make the world a better place for future generations or watch it drown? As Ronald Reagan says “Preservation of our environment is not a liberal or conservative challenge, it’s common sense.”

The Facts


Ice Reserves

The Antarctic and Greenland ice caps have been melting at an average of 5 times faster in the last 10 years compared to the ten years before that. Ice caps represent 68.7% of all freshwater on earth and if they were to melt the global average sea level would rise by 70m

Sea Level

Over the last century the global sea level has risen by an average of 1.7mm per year. However, in recent years this rate has increased to 3.2mm per year. Furthermore, scientists predict a 1 meter increase by the year 2100, that would mean a futher 300% increase from the current rate.

Carbon Emmisions

According to The United States Environmental Protection Agency, since 1970, CO₂ emissions have increased by a 90%, with emissions from fossil fuel combustion and industrial processes contributing about 78% of the total greenhouse gas emissions increase from 1970 to 2011