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A report suggests that large parts of some of the world’s biggest coastal cities will be submerged by 2050 due to rising sea levels. However, this intrusion from sea-level rise is already being seen in the form of seawater that is contaminating drinking water. 

When seawater finds its way into aquifers due to sea-level rise, it contaminates sources of drinking water. An aquifer is a layer underneath the land surface consisting of permeable rocks, rock fractures, or unconsolidated materials that can hold and transmit groundwater.

Many low-lying areas around the globe are already witnessing an increase in incidences where seawater is contaminating the groundwater. 

India, for example, has 4% of the world’s freshwater reserve. This put the country’s expanding population at risk since the demand for water has skyrocketed.

Since 1950, per capita availability of water in India has reduced by 70% due to high demand from consumers, as well as agriculture, and it is expected to decline even further in the years to come. Furthermore, the cyclonic storms that hound India’s coastline bring more trouble by flooding its low-lying areas with saline water. 

According to a study on the status of groundwater in India, Odisha – an Indian state on the eastern coastline- experiences 4 to 15 cyclonic disturbances a year. As a result, low-lying agricultural areas get submerged in seawater. Due to this exposure, aquifers get contaminated while wells start to yield saline water. This will eventually lead to water shortages and contamination in the region.

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Another report indicates that Chennai is the city most affected by seawater intrusion in the country with 14km of seawater intrusion. The report adds that the total affected area in India stands at nearly 2 600 km – an increase of 500 km between 2007 and 2017. 

The 20th century witnessed an increase in the mean sea level by 11-16 cm due to the climate crisis. Under a higher emissions scenario, sea-level rise this century could exceed 2m, while even immediate cuts to carbon emissions would result in a 0.5m rise.

These events further elevate the problem of seawater intrusion. While melting ice sheets are increasing sea levels, droughts reduce the downstream flow of rivers, a natural process which stops seawater from entering inland.

An article in Yale Environment 360 states that in the US, the Delaware River- which supplies water to millions in Philadelphia and southern New Jersey- is at risk of seawater contamination due to reduction in downstream supply due to droughts. If the trend continues, saline water will eventually find its way into consumable water reserves. Amy Shallcross, manager at Water Resource Operations, DRBC further adds, “There is a concern with climate change that we could get another record drought when we would run out of storage, in which case there would be added force pushing salt upstream from the ocean and less water to push it downstream.” 

The Biscayne Aquifer, which supplies water to 6 million people in southern Florida, is already dealing with the problem of saline water intrusion. Higher sea levels have reduced the gradient that blocks seawater from entering the interiors. As a result, canals aren’t functioning by pumping out fresh water from the depths of Florida. Sea levels in Florida are 20cm higher than in 1950. 

At the moment, we are fighting a battle on two fronts. The climate crisis is causing frequent droughts that dry up the rivers which pump freshwater into the sea. This process keeps the saline water from entering inland. On the other hand, our glaciers are melting due to rising temperatures that increase sea levels, thus increasing the chances of seawater penetration. 

While drinking water contamination from sea-level rise is a reason to worry, the ecology is also getting affected by seawater intrusion. Any life form that depends on freshwater for survival is at risk of perishing after being exposed to saline water. 

For example, in the Sundarbans, home of the world’s largest mangrove forest, royal Bengal tigers and various other species that thrive in this ecosystem are at risk due to the rising water level in the Bay of Bengal, which is rising twice as fast as the global average. As a result, the high species diversity observed in the region will decline if no action is taken.

The findings also suggest solutions to help stop seawater intrusion, including building percolation ponds, a technique in which rainwater is collected in large open ponds or areas surrounded by banks. The water then infiltrates into aquifers if the pond is permeable and if the aquifers are near the surface. Other methods include building desalination plants, regulating the use of groundwater, or moving water treatment plants further upstream, however this is an expensive process.  

While these solutions give a short term respite, we must address the root cause of the problem which is climate change. We can do so by adopting more sustainable lifestyles that stop the negative effects of human activities on the planet. On a grander scale, we need to reduce our global greenhouse gas emissions. Failing to do so will render large swatches of the planet literally uninhabitable.


In mid-May, a pocket of scorching hot air flowed north from Siberia and fanned out across the Arctic Ocean reaching as far as Greenland and triggering an unprecedented heatwave. In Khatanga, a Russian village above the Arctic Circle which normally remains below freezing in the spring, the mercury hit 25 degrees Celsius, smashing the previous record by 13 degrees C. According to temperature records which go back to 1958, no other year has been hotter in the Arctic for this same time period. This weather anomaly has since ignited significant wildfires in Russia and contributed to the rapid melt-out of sea ice in the Arctic Ocean — possibly jumpstarting this year’s melt season. Indeed, sea ice is currently at its fourth lowest for this time of year since record-keeping began in the 1970s. Could this increased Arctic ice melt actually be linked to the COVID-19 pandemic?

“Overall, this winter wasn’t particularly warm, but now that’s flipped around in the last month and we’re really seeing the effects,” says Mark Serreze, director of the National Snow and Ice Data Center (NSIDC). “Big holes are opening up along the Siberian coast where it’s been the warmest.”

This Central Arctic heatwave may not be a one-off event only occurring in spring 2020, researchers suggest. Rather, if levels of global industrial air pollutants continue to fall due to the COVID-19 pandemic, the current Arctic warmth could be a bellwether of what’s to come later this summer when sea ice melt annually kicks into high gear.

According to a recent study in Nature Climate Change, daily global greenhouse emissions dropped by 17 percent in early April compared to last year’s numbers. If maintained, a decline in carbon pollution is a good thing for global climate stability and for avoiding the most severe consequences of climate change.

But in the short-term, a drop-off in atmospheric pollutants can actually cause a slight increase in global warming. That’s because heat-trapping gases such as carbon dioxide and methane aren’t the only thing released by burning fossil fuels. Sulphate aerosols are also spewed into the air, and these aerosols are known to produce a cooling effect on the planet, mitigating some of the warming from greenhouse gases. If aerosol emissions are going down, it’s possible we could see a slight temperature bump upward this spring and summer which could speed up Arctic sea ice melt.

“Ultimately we need to eliminate sulfur pollution and sulphate aerosols, which cause lots of other problems too, such as acid rain,” says Michael Mann, a renowned climatologist and director of the Earth System Science Center at Pennsylvania State University. “But it is a ‘Faustian bargain’ in the sense that [reductions in aerosols] unmasks some of the global warming that had been hidden for decades by the sulphate aerosol pollution.”

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Sulphate Aerosols Reflect Solar Heat

Unlike greenhouse gases which can remain in our atmosphere for years, sulphate aerosols are relatively short-lived. They’re typically washed out of the troposphere in a matter of weeks, and therefore need to be constantly replenished by industry to maintain their cooling benefits.

Sulphate aerosols counteract planetary warming in two different ways. For one thing, they’re highly reflective. “They reflect a lot of sunlight back into space, rather than have it absorbed and warming the earth,” explains Michael Diamond, an atmospheric scientist at the University of Washington. “They can also change cloud properties. Clouds aren’t just pure water — they need a seed or a nuclei to form.” Sulphate aerosols provide such nuclei for water to condense around, creating a greater abundance of clouds, and more reflective clouds as well — an effect known as ‘cloud brightening.’

“It’s like a lot of little mirrors reflecting sunlight back to space,” says Diamond.

The United Nations Intergovernmental Panel on Climate Change has long struggled to quantify the exact cooling impact of sulphate aerosols. According to Mann, aerosols have likely been responsible for offsetting about 0.4 degrees Celsius of global surface warming, and a much larger amount — more than 1 degree C (1.8 degree F) — in the mid-latitude regions during summer when there is more sunlight to reflect back.

An AGU Advances study published in March 2020 sought to further quantify the aerosol impact on cloud brightening, with researchers zeroing in on a shipping lane in the southeast Atlantic. Diamond, who served as lead author of that study, found that sulphate aerosols from shipping were responsible for reducing warming by two watts per meter squared. To put that in perspective, greenhouse gases are responsible for warming of about 4 watts per meter squared. When Diamond and his team calculated the global cooling effect from all industrial activity around the world, on land and at sea, they found that sulphate aerosol-seeded clouds masked about a third of all warming from greenhouse gases.

covid-19 arctic ice melt
As sunlight intensifies in the Arctic during the spring and summer, clouds matter; the fewer the clouds, the more sunshine, and the more melt (Source: VisualHunt).

And Then Came COVID-19

Researchers around the world are now trying to parse out how Coronavirus lockdown measures have affected global emissions. In the Nature Climate Change study published last month, an international team of scientists found that daily CO2 emissions dropped by 17% at the peak of the coronavirus shutdown. However, emissions are creeping back up as shelter in place measures are relaxed. By year’s end it’s expected 2020 CO2 emissions will end up between 4 and 7% lower than 2019 — the biggest drop since World War II.

Another study published in Geophysical Research Letters in May found that nitrogen dioxide pollution over China, Western Europe, and the United States decreased by as much as 60% in early 2020 compared to the same time last year. And a study focused on northern China found that levels of Particulate Matter 2.5, a notable human health hazard, decreased by approximately 60% in January and February.

But Diamond says the picture is a bit more muddied when it comes to aerosols. His research group has been examining emission levels from China in February 2020. “In the clouds over the South China Plain and East China Sea, you don’t see any difference in the size of those cloud droplets,” he says, indicating there hasn’t been a significant change in the level of sulphate aerosols in the atmosphere. One explanation could be that though passenger traffic has fallen during the pandemic, electricity generation for industrial combustion is only down by about 10%, according to data from the Chinese government.

However, coincidentally, in January 2020, the United Nations International Maritime Organization implemented a policy banning ships from using fuels with a sulphur content above 0.5%, resulting in a seven-fold reduction from 3.5%. “Any signal we’re seeing in international shipping right now is a combination of this policy and the pandemic,” says Diamond.

Sulphate aerosols have been decreasing in the United States under the Clean Air Act as well, says Patricia Quinn, atmospheric chemistry leader at the U.S. National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Lab. Since the 1980s, sulphate aerosols have likely declined by between 30 and 50 percent. “It’s not serving as big as a mitigator [of warming] as it once was,” Quinn said. “Coal-fired power plants — a major source — aren’t being used as much as they were a few years ago because it’s a more expensive form of energy production now.”

Indeed, in a 2017 study, scientists posited that the sulphate aerosols released due to human activity masked the decline in Arctic sea ice in the mid-20th century, before the Clean Air Act went into effect, and actually led to periods of ice growth.

A Riddle, Wrapped in a Mystery, Inside an Enigma

So how might a reduction in sulphate aerosol levels affect the Arctic during the Coronavirus pandemic?

Quite a lot — maybe. Juan Acosta Navarro is an environmental scientist at the Barcelona Supercomputing Center. He says that, “The Arctic appears to be quite sensitive to changes in emissions of sulphate aerosols.” Using earth system computer modelling, his simulations showed that sulphate aerosol reductions in Europe since 1980 could potentially explain a significant fraction of Arctic warming over that period. Specifically, the Arctic received approximately 0.3 watts per meter squared of energy, warming by 0.5 degrees C (0.9 degrees F) on average as Europe’s sulphur emissions declined. “We conclude that air quality regulations in the Northern Hemisphere, the ocean and atmospheric circulation, and the Arctic climate are inherently linked,” his 2016 Nature Geoscience study stated.

But weather variability and climate system chaos — as always — still provide an obstacle to making any long-term predictions about the sea ice outcome this year, or any year.

“Patterns of the atmospheric circulation are going to play a huge role in what summer looks like,” says NSIDC’s Serreze. “Could we be looking at a record high global temperature this year? Maybe. We’re kind of on track for that right now. What’s going to happen with the sea ice? We know it’s well below average right now, but [weather variability] can counter the effects of greenhouse gases” in the short term.

Still, he’s energized — certainly not by COVID-19, but by the prospect of being able to test the role of sulphate aerosols on global warming. “Here we are, in a serendipitous sense, presented with this incredible global experiment. We can perhaps see what the effects are [of sulphate aerosol reduction] and how this relates back to the sea ice.”

“Every cloud has a silver lining,” he concludes.

Featured image by: Polar Cruises

This article was originally published on Mongabay, written by Gloria Dickie , and is republished here as part of an editorial partnership with Earth.Org. 


In early July, Venice tested its long-delayed flood barriers, in a public demonstration of the strength of the barriers months after floods swamped the city. 

The multi-billion-euro Mose (Experimental Electromechanical Module) scheme, which was still incomplete a decade after it was due to come into service, has been plagued by corruption and ever-inflating costs. The test saw all 78 giant yellow sluice gates rising above the water for the first time, but it is not expected to be fully functional until next year. Once fully operational, the Mose flood barriers system is designed to protect Venice from tides of up to three metres, which is well beyond the current record, but some experts are concerned that it will be overwhelmed by the rising seas that recent climate change models have predicted. 

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Additionally, the test was carried out in ideal conditions, far different from the 100kph winds and three metre waves that struck the city last November. Further, while all gates can go up, not all can currently go back down into their housings on the sea floor, due to sand in the works.

In November 2019, the worst floods in more than 50 years submerged 70% of the city at one point and rose to over 1.8 metres in some areas. Venice’s floods, called “acqua alta” (high water) are caused by rising sea levels and unusually high tides due to land subsidence that has caused the ground level of the city to sink. 

There are also concerns that Italy won’t be able to keep up with Mose’s astronomical costs, estimated at around €100m a year. Adding to the government’s borrowing to restart the economy following the COVID-19 pandemic that may push public debt to 160% of GDP, this may be an expense that is difficult to maintain.

To keep the sea level in the city from rising any more than it already is, keeping big ships out of the lagoon may help. However, Pietro Teatini, professor of hydrology at Padua university, believes that Venice should be lifted. He says that doing this by 20-30cm would help and to do this, seawater could be pumped into the already salty aquifers below the city. In 2008, it was estimated that a pilot scheme would cost €11.1m to launch and €1.4m a year to run; the full project around €80m and €10m a year. In comparison, the Mose scheme has devoured €6bn. 

Featured image by: Roberto Trombetta

In 2007, Marc Collins Chen, minister of tourism of French Polynesia, said that a third of the French Polynesian islands would be submerged by either 2035 or 2050- “depending on which scientist you spoke to.” An estimated 2.4 billion people- 32% of the world’s population- live in a coastal region and will likely be impacted by rising sea levels as a result of the climate crisis. In late 2018, Chen pioneered the concept of off-shore urban infrastructure, or ‘sustainable floating cities’, in order to tackle the issue of rising sea levels, founding the company Oceanix to put his vision into action.

In a 2019 meeting with the UN, Chen and a group of specialists, including zero waste experts, proposed their idea of what sustainable floating cities would encompass. Their plan involves 4.5-acre hexagonal floating islands- about the size of three and a half football fields- that each house 300 people. These islands are the foundation upon which these settlements would be built. A village could be formed by combining six of these islands and connecting them via an open port. The idea is that as long as each island operates an essential service such as healthcare, education, spirituality and commercial services, they could be fully functional communities. Furthermore, outside these communities there could be uninhabited functional islands for energy collection and crop yielding.

Furthermore, Chen claims that marine life would not be threatened under his vision as ‘the technology exists for us to live on water, without killing marine ecosystems’. There have been several plans for floating homes and apartments but what makes Oceanix’s plan more viable is their plan for scalability, such that scaling up and looping six villages together would result in a city of 10 800 people. These floating islands are intended to be self-sustaining in terms of their energy, food and water production. Ideally, they would be efficient as well through their repurposing of waste materials produced, and fuelling all operations with energy produced by the islands themselves in a closed loop system. These efficiency goals are ambitious, and take inspiration from cities such as Stockholm, Amsterdam and Copenhagen (this city is planning to become the first carbon-neutral city by 2025) that are making efforts to steer away from their reliance on fossil fuels. 

The feasibility of the project hinders its implementation. Much of the technology to make this happen will need to be either invented from scratch or wholly adapted to fit the floating city. Further, Oceanix has yet to formulate a concrete business plan that would render them eligible to apply for green venture capital funds or government grants which aim to promote sustainable development. Furthermore, one of Chen’s main goals is to make these islands affordable but given the amount of investment and work that the first prototypes would need, this may be difficult to achieve. Moreover, the governance of such settlements has come into question, as it is unclear how these islands will be run, if inhabitants will have to commute to the mainland, and how they fit into more established economic systems. 

Despite the technicalities, the point of such a concept is to revolutionise the way that we live, and question the systems we have in place. In a world that is in need of change, it’s these crazy ideas that will breed the innovations and sustainable technologies that are needed to combat pressing environmental concerns.

Featured image: Oceanix’s rendering of its sustainable floating cities (Source: BIG-Bjarke Ingels Group). 

Mangrove forests won’t survive sea-level rise and will disappear by 2050 if greenhouse gas emissions aren’t reduced, according to a new study. 

How Does Sea-Level Rise Affect Mangrove Trees?

The study, published in the journal Science, used sediment data from the last 10 000 years to estimate the chances of mangrove survival based on rates of sea-level rise. It examined sea-level rise across 78 locations and explored how mangroves responded as the rate of sea-level rise slowed from more than 10mm yearly 10 000 years ago (as a result of glacial ice melt) to nearly stable conditions 4 000 years later. The storage of carbon as mangrove forests expanded during that period means that these ecosystems are important carbon sinks.

It found that when rates exceeded 6mm per year, similar to estimates under high-emissions scenarios for 2050, mangroves were likely to stop keeping pace with the rising water levels. Instead, mangroves are more likely to survive when sea-level rise is less than 5mm per year- which is projected for low-emissions scenarios this century. 

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Erica Ashe, a postdoctoral scientist at Rutgers University- New Brunswick and co-author of the study, says, “Under high-emissions scenarios, rates of sea-level rise on many tropical coastlines will exceed 7mm per year, the rate at which we concluded there’s a 6.2% probability mangroves can sustain growth. The loss of these mangrove ecosystems could result in increased carbon dioxide in the atmosphere and fewer vital buffers against storm surges in the long run.

Mangrove trees and forests are valuable coastal ecosystems found in Florida and Bangladesh, as well as other warm climates that store large amounts of carbon dioxide, reduce erosion from storm surges, currents, waves and tides, help protect coastlines and provide habitat for fish and other species. There are about 80 species of mangrove forests and they line nearly 3 000 km of shoreline. 

They naturally move inland if they can’t build vertically, but human development along coastlines hinder this movement. These areas are also deforested to make room for shrimp farms and other forms of aquaculture, as well as for their wood. They need freshwater to survive and can die when dams and other upstream developments stem the flow of rivers. 

Studies show that, pound for pound, mangroves can sequester four times more carbon than rainforests can. Most of this carbon is stored in the soil beneath the trees. In 2000, mangrove soil held around 6.4 billion metric tons of carbon. Between 2000 and 2015, up to 122 million tons of this carbon was released due to mangrove forest loss. 

Their monetary value is equally as important as their carbon-sequestering abilities. Researchers estimate the monetary value of the ecosystem services provided by these trees at US$194 000 per hectare annually. Multiplied by their global extent, the world’s remaining mangroves provide around $2.7 trillion in services every year.

The rate of sea-level rise has doubled from 1.8mm per year over the 20th century to 3.4mm per year in recent years. The scientists stress the importance of mitigating this rapid sea-level rise and ensuring that coastal adaptation measures allow mangrove forests to expand across coastal lowlands and not disappear before our eyes.

Featured image by: James St. John

Jakarta, the capital of Indonesia, sits precariously on the Pacific Ring of Fire (an area of high tectonic activity) and annually experiences severe flooding, monsoons, tsunamis, and earthquakes, the effects of which are getting more extreme as the climate crisis worsens. It is also one of the fastest sinking cities in the world. To escape the rising sea levels, the Indonesian government is moving its headquarters to Borneo, the island famous for its orangutans. What are the social and ecological consequences of such a move?  

In April 2019, Indonesia’s president Joko Widodo announced his cabinet’s plans to move the capital from Jakarta to a more central location in the Indonesian archipelago. While some welcomed this as a sign that the Java-based government is taking greater interest in the development of its more remote communities situated on other islands, the reality is that at the current rate of rising sea levels and sinking foundations, areas of Jakarta will be entirely submerged by 2050

How is Indonesia affected by sea level rise? 

The land under Indonesia’s current capital is sinking at an average rate of 1-15 cm per year, with the rates of sinking unevenly distributed around the city’s districts, from 1cm per year in the south to up to 15cm in the west and 25cm in North Jakarta. This phenomenon is known as land-subsidence, and is predominantly a consequence of unmoderated human activity. Land-subsidence is caused by the extraction of large volumes of groundwater from aquifers beneath the city, and in the case of Jakarta, the sinking is further exacerbated by the soft, swampy ground on which the city sits. Despite some of this extraction being illegal, the city does not have the resources to police it effectively and, due to the inadequate provision of drinkable water to many of its districts, the local populace often has no alternative.

Land-subsidence is a serious issue for locals, as it increases the severity and duration of flooding, preventing run-off from finding its way back into the sea and rivers. Even in relatively dry periods, the sinking causes cracks in walls and uneven surfaces leading to structural instability in buildings that frequently needs to be patched up. 

What will happen to Jakarta once the administrative buildings and government officials have been relocated? Plans for the new capital city only accommodate 1.5 million of the 10 million people currently living in the capital. After prioritising civil servants and their families, the remaining places will likely go to the wealthy or well-connected, leaving the middle- and lower-class majority of Jakarta to address the increasingly urgent issues of land subsidence, flooding, traffic congestion and air pollution themselves. In an interview last year, President Widodo agreed that Jakarta must embark on the Giant Sea Wall project, discussions of which began a decade ago. The project has been repeatedly postponed amid debates about the cost of the project and the impact it could have on the local coral reef and fishing industry.

The finalised location for the new capital, as announced in August of last year, is the province of East Kalimantan on the southern, Indonesian-owned end of the idyllic and sparsely populated island of Borneo. This island was the strong favourite for several reasons: firstly, that it would ease the overcrowding of Java, the most densely populated island in Indonesia, and secondly, it would separate the governmental centre from the economic hub, redistributing wealth away from Java which currently contributes 58% of Indonesia’s GDP. In comparison, Kalimantan contributes less than 9%, and Bali-Nusa Tenggara and Maluku-Papua, the most eastern regions, contribute 3% and 2.5%, respectively.

Finally, moving the capital to a more central location in the archipelago would give the impression of a more unified country and a government that takes greater interest in its more remote, isolated regions in the east, whose development has long been neglected. 

There have been mixed feelings regarding the move amongst the locals of East Kalimantan, with some hoping that the increased development in the area will result in better education and employment prospects. On the other hand, there is concern among locals and environmental groups about what the large influx of immigrants, and the accompanying development, will mean for the pristine tropical rainforests and biodiversity in the region. Not only would there be grave regional implications of further pollution and deforestation, but the planet’s health would also be compromised further. Borneo has been called the ‘lungs of the world’ due to the large amounts of CO2 the heavily forested island absorbs, similar to the Amazon rainforest. With the introduction of large-scale human activities such as mining and logging, Borneo may risk emitting more greenhouse gases than it absorbs. President Widodo has promised to preserve the protected rainforest in the region, a promise which will hopefully be honoured. 

It remains to be seen to what degree the move will be a success in terms of social welfare and economic growth for remote Indonesia, and for those inhabitants left behind in Jakarta. In the meantime, it is imperative that the government boosts efforts to reduce the impacts of rising sea levels through physical buffers and reducing emissions.

Featured image by: Dino Adyansyah

The climate report warns of increasing sea-level rise as the polar ice caps continue to melt and says that as a result, intense storms, coastal flooding, and loss of marine life due to global warming are already inevitable. But the world still has time to avert even more severe consequences.

A new report from the Intergovernmental Panel on Climate Change (IPCC)  warns that extreme events caused by sea-level rise from melting ice caps – high tides, intense storms, and massive floods that used to occur once a century- will strike every year worldwide by 2050, no matter whether global emissions are curbed or not. 

The report, written by more than 100 climate and marine scientists from more than 36 countries, explores the links between oceans, glaciers, ice caps and the climate. It states that sea level rose globally by about 15 cm during the whole of the 20th century, and it is currently raising more than twice as fast, and accelerating over time. 

How does greenhouse gas emission affect sea level rise?

If greenhouse gas emissions are reduced significantly, preventing a 2C temperature increase, global average sea levels could still rise by 30 to 60 cm above current levels by 2100. If emissions keep climbing instead of falling, and it causes 2C or more temperature increase, sea levels could rise by one metre by the end of this century — ten times the rate in the 20th century. At this rate, the rise could exceed five metres by 2300.

The report warns that the world could lose many of its glaciers by the end of this century because of global heating. Small glaciers in Europe, eastern Africa, the tropical Andes, and Indonesia are expected to lose more than 80% of their current ice mass by 2100. “Many glaciers are projected to disappear regardless of future emissions,” the report says. “About 20 cm of sea-level rise from melting glaciers alone is likely in a 2C scenario. If emissions are drastically cut and warming is stabilised at 1.5C, glacier melt from the warming already locked in would contribute about 8.9 cm of sea-level rise.”

As glaciers continue to melt in Greenland and Antarctica, the sea-level rise is further accelerating. “In recent decades the rate of sea-level rise has accelerated, due to growing water inputs from ice sheets in Greenland and Antarctica, in addition to the contribution of meltwater from glaciers and the expansion of warmer sea waters,” says Valérie Masson-Delmotte, co-chair of a UN Intergovernmental Panel on Climate Change group that produced the report. “This new assessment has also revised upwards the projected contribution of the Antarctic ice sheet to sea-level rise by 2100 in the case of high emissions of greenhouse gases.”

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Climate change is devastating the oceans and polar regions as never before, the report warns.

In the Himalayas, glaciers feeding ten rivers, including two prominent trans-boundary rivers in Asia — the Ganges and Yangtze, could shrink dramatically if emissions do not fall, hitting water supplies across the continent. Thawing permafrost in places like Alaska and Siberia could release vast quantities of greenhouse gases, potentially unleashing feedback loops driving faster warming.

The report projects that 20-90% of the world’s current coastal wetlands would disappear by 2100, depending on different sea-level scenarios. Since 1950, more than 50% of the world’s wetlands have already vanished.

Meanwhile, marine heatwaves are becoming more intense, devastating coral reefs — including much of Australia’s Great Barrier Reef. The heatwaves have grown more intense and doubled in frequency since 1982 making oceans hotter, more acidic, and less oxygenated. They would be 20 times more frequent in a 2C world, and if emissions push temperatures past that point, they would happen 50 times more often. 

The world still has time to avert the severe consequences of climate change by curbing global warming below 2C. “We will only be able to keep global warming to well below 2C above pre-industrial levels if we effect unprecedented transitions in all aspects of society, including energy, land and ecosystems, urban and infrastructure as well as industry,” says Debra Roberts, a co-chair of IPCC working group. “The ambitious climate policies and emissions reductions required to deliver the Paris Agreement will also protect the ocean, and ultimately sustain all life on Earth.”

Sea-level rise is threatening West Africa. Growing stronger by the year, the tides push wave after wave into cities and villages, decimating dwellings and farmlands.  

The western coast of Africa, stretching more than 6500km from Mauritania to Cameroon, is in peril. Caused by global warming, rising sea levels are causing massive erosion — in some places eating away more than 30 metres of land in a single year.  

The more frequent occurrence of damage caused by rise in sea level affects different communities in specific ways, depending on population size, wealth, and geography. Governments and transnational organisations need to prepare contextualised response plans for affected communities.

West Africa Sea Level Rise

Sea levels are expected to rise by more than 76 cm around the world by the end of this century, but they are expected to rise faster than the global average in west Africa, where the coastal areas host about one-third of the region’s population and generate 56% of its GDP. A recent World Bank study shows that flooding and coastal erosion due to sea-level rise cost the region about $3.8 billion and cause 13,000 deaths in just one year.  

Ghana — the fastest growing economy in the world — is among the worst affected countries in the region. Coastal erosion at its 580km coastline comprising of sandy beaches and outcrops has consumed areas like Keta, Ada, and Shama. Rising temperatures have triggered the migration of fish stocks while salinisation has contaminated farmlands and freshwater reserves affecting the livelihoods of millions of fishermen and farmers. Frequent inundation has led to the destruction of commercial buildings, houses, and even human lives. 

Once a thriving trading hub, Ghana’s Keta city has suffered massive coastal erosion in recent decades that forced more than half of the population to flee. Fuveme — a coastal village in Keta that lies between the Gulf of Guinea and the Keta Lagoon — has already been reduced to an island forcing thousands of families to migrate to the inland. 

Senegal, another west African country, has been witnessing the devastating effects of sea-level rise this decade. The country’s famous colonial city Saint-Louis — a UNESCO World Heritage site with a population of 300,000 people — is seeing houses destroyed, streets flooded, and crops damaged by the encroaching saltwater.

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Encroaching waters off the coast of west African countries are destroying homes, schools, farmlands, and a way of life.

Perched at the edge of the Atlantic Ocean and at the foot of the Sahara Desert, the city is vulnerable to the rising sea because nowhere in the city is higher than 4 metres above the sea level. Rising tides have led to serious coastal erosion and forced schools, mosques, and hundreds of houses to be evacuated. Seawater has decimated crops that once thrived on the freshwater flow from the Senegal River.  

Nigeria, the most populous country in Africa, too has low lying cities that are being destroyed by the sea. Its most populous city Lagos, a megacity located next to the Atlantic Ocean, consists of a mainland and a series of islands with an estimated population of 21 million. A large number of city residents who live on waterfront slums with no proper drainage or water systems have been suffering due to rising sea levels as their dwellings get flooded frequently.

Other west African countries such as Benin, Cote d’Ivoire, and Togo face a high rate of coastal erosion. A World Bank study reveals that 56% of the coastline in these countries has been eroding 2 metre per year. Damages from the sea-level rise cost the government of Cote d’Ivoire nearly $2 billion — 4.9% of its GDP, while it cost the Benin government $229 million — 2.5% of the country’s GDP. 

Tackling Climate Change in West Africa

It would require hundreds of billions of dollars to protect cities and villages from sea-level rise in West Africa. Costs will continue to increase in the future as sea levels rise and populations in the coastal areas grow. But, most countries cannot afford sea-level rise adaption strategies as they are already struggling with immediate poverty challenges. 

However, there are external financial sources the west African governments can depend on.  One of them is international climate funds disbursed among the countries struggling with issues caused by climate change. 

Governments should direct funds towards education and agricultural strategies that are adaptive to environmental changes. Farmers can employ strategies such as floating cultivation, crop rotation and seasonal water management. Ultimately, states should begin to invest in programmes involving a managed retreat for rural coastline residents. States must facilitate these migrations by incentivising people to move early. Governments can expand public transportation between inland and coastal settlements, so that individuals who move inland can continue to work on the coast for as long as possible, or vice versa. Delaying relocation until the conditions become untenable can be traumatic for communities and local economies. A comprehensive managed retreat programme can be the most efficient way for communities to maintain economic output over time.

Imagine that the internet is suspended for days; no email, no social media, no online banking, and no streaming services. Sea-level rise caused by climate change could make the likelihood of a massive internet outage more likely.


Sea-level rise might cause massive internet outages that could disrupt modern life and inflict major damage on the global economy in the next decade.

How does sea level rise cause internet outage?

According to a recent study by the University of Wisconsin-Madison and the University of Oregon, more than 6500 kilometers of buried fiber optic conduit in the United States will be underwater due to sea-level rise in less than 15 years. More than 1,100 traffic hubs will be inundated in major cities like Seattle, Miami, and New York. Thousands of companies and millions of people across the world will be affected because of the subsequent internet blackout.

“The impacts (of infrastructure damage in US coastal cities) could ripple out and potentially disrupt global communications,” says the study’s lead author Ramakrishnan Durairajan.

Internet infrastructures in the US have already faced the wrath of climate change induced extreme weather events. In 2012, when Hurricane Sandy hit the East Coast, millions of residents in the states of New York, New Jersey, and Connecticut faced a complete internet blackout for days. Several central offices of major Internet Service Provider (ISP) Verizon in lower Manhattan, Queens, and Long Island City were flooded.

The new research — the first-ever study to look at the impact of climate change on the internet — warns that communication infrastructures in the US are much more vulnerable than previously imagined.

“Our analysis is conservative in that we only looked at the static dataset of sea-level rise and then overlapped that over the infrastructure to get an idea of risk,” Durairajan says. “Sea-level rise can have other factors — a tsunami, a hurricane, coastal subduction zone earthquakes — all of which could provide additional stresses that could be catastrophic to infrastructure already at risk.” 

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Seawater inundation projected for New York City by 2033 and its effect on internet infrastructure. Anything in the blue shade is estimated to be underwater in 15 years.

The buried fiber optic cables, data centers, traffic exchanges, and termination points are the nerve centers and arteries of the vast global information network. They are not waterproof like marine cables that ferry data under the ocean. When sea-levels rise, these conduits and cable landing points will be permanently submerged. Seawater will corrode connectors and optical transponders of the cables. Major ISPs like CenturyLink, Inteliquent, and AT&T will be affected.

“Most of the damage that’s going to be done in the next 100 years will be done sooner than later,” says the study’s senior author Professor Paul Barford. “That surprised us. The expectation was that we’d have 50 years to plan for it. We don’t have 50 years.”

Researchers estimate that over 771 Points of Presence (PoPs) — the infrastructure that allows remote users to connect to the internet — and 235 data centres will be affected when sea levels rise by one foot in 2030. As many as 780 PoPs and 242 data centres will be submerged by 2075 when the seawater rise by four feet. 

An internet outage due to sea-level rise even for a brief period will create significant detrimental impacts on economic activity around the world. A report from Brookings that examined the economic effects of 81 internet shutdowns that took place in the span of a year estimates that internet blackout cost a minimum of $2.4 billion in GDP, globally. The country most economically harmed by internet shutdowns was India—by a long shot—which lost out on nearly $1 billion in GDP. The bill for Saudi Arabia’s blackouts came to $465 million, Morocco’s was $320 million, and Iraq’s amounted to $209 million.

Greenland is the world’s largest island with a vast body of ice sheet covering 1,710,000 sq km, roughly 80% of the surface. The climate here has been exceptionally stable in the past 10,000 years. But the Greenland ice sheet is now changing drastically.

Greenland ice sheet is a relic from the ice age, when gigantic glaciers covered vast stretches of the Northern Hemisphere. The ice in most places–Canada, the northeastern regions of the US, and Scandinavia–had melted away about 10,000 years ago. Although the Greenland ice sheet has persisted so far, it may not, anymore.

Authors of a new study published in the journal Proceedings of the National Academy of Sciences estimates that the Greenland ice sheet is now sloughing off an average of 286 billion tons of ice per year. Two decades ago, the annual average was just 50 billion. An analysis of satellite data reveals that the mass loss has increased sixfold since the 1980s.

Another study published last year reconstructed the changes in Greenland’s ice sheet over the past 350 years using ice cores and satellite data, and cataloged the history of variations in the ice sheet.

The research team found that melting in Greenland ice sheet started to pick up shortly after the dawn of the Industrial Revolution in the mid-1800s, when humans started burning coal, oil, and natural gas in huge quantities, sending tons of heat-trapping greenhouse gases into the atmosphere.

However, it’s only over the last 20 years that the melt rate has definitively increased beyond natural variability. One section of the ice sheet saw its melt intensity surge 575 percent over the last 20 years compared to pre-industrial times.

Sled dogs pull researchers from the Danish Meteorological Institute through meltwater in Greenland. Source: Steffen M Olsen/Twitter

Greenland gains some ice in the winter and loses some in the summer, but as the planet has warmed, the latter has outpaced the former. The ice sheet itself is also changing. The firn layer in the ice sheet, the boundary between snow and ice, is heating up and becoming denser. So water that would ordinarily trickle down through the snow and refreeze runs off the ice sheet instead.

The ice is also getting darker, as soot carried through the air and microorganisms like algae settle on the ice. Dark ice absorbs more solar energy and melts faster.

Besides global warming, a negative phase of the North Atlantic Oscillation (NAO)— a natural, irregular change in atmospheric pressure over the North Atlantic Ocean– also causes the rapid ice melt.   

What does it mean to you?

Although Greenland is located faraway at the northern end of the Atlantic Ocean, the sheer volume of ice melting into the ocean will have global repercussions affecting all of our lives.

Nasa reveals that if the Greenland ice sheet were to completely melt into the ocean, sea levels would rise by about 7 meters (23 feet) globally. The Earth’s rotation would slowdown lengthening the days. 

Greenland’s ice caps are currently the biggest single source of meltwater adding to the volume of the world’s oceans. They contribute about 20% of global sea-level rise, which is running at 4mm per year. All the melted ice has already contributed to more than 1.5 cm of global sea-level rise since 1972. Half of that increase came about in the last eight years alone. This pace is primed to double by the end of the century, according to the recent models used by the UN Intergovernmental Panel on Climate Change.

Rising water has already swallowed up at least eight low-lying islands in the Pacific Ocean. It also has increased coastal erosion. In Bangladesh and Thailand, coastal mangrove forests–important buffers against storms and tidal waves–are giving way to ocean water. Low-lying island nations, especially in equatorial regions, have been hardest hit. 

Vietnam is among the most vulnerable nations to global sea-level rise

A World Bank study found that if sea level were to rise by 1 metre, an area of 74,000 sq km in twelve countries–Brunei, Cambodia, China, Indonesia, North and South Korea, Malaysia, Myanmar, Papua New Guinea, Philippines, Thailand, and Vietnam–would be submerged permanently. Coastal communities in these countries will continue to face billion-dollar disaster recovery bills as flooding becomes more frequent and storms become more intense.  

Besides rising sea level, the relentless stream of meltwater threatens to disrupt oceanic currents stemming from the Gulf of Mexico that warm Europe’s coasts, contributing in no small measure to upkeeping the temperate climate north of the Mediterranean. Altering these currents, collectively known as the Atlantic Conveyor could lead to considerable changes in climate and rainfall patterns throughout the Northern Hemisphere. 

Ice sheets act as a protective cover over the land and ocean. They reflect the majority of the solar radiation back into space, keeping the planet cooler. Once they melt away, the excess heat would remain in the atmosphere causing a so-called feedback loop, which will warm the planet further. This temperature increase in air and ocean will create more frequent and intense coastal storms like hurricanes and typhoons in the Northern Hemisphere.  

Letting global temperatures get any higher could lead to irreversible mass loss of ice in Greenland. Cutting greenhouse gas emissions as aggressively as possible to limit the warming is the only solution. As the Intergovernmental Panel on Climate Change pointed out, limiting the temperature to 1.5C by 2050 would require an unprecedented global coordinated effort. 



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