When UN climate negotiators met for summit talks in Nov 2017, there was a new figure on the table: 3C. Until now, global efforts such as the Paris climate agreement have tried to limit global warming to 2C above pre-industrial levels. However, with latest projections pointing to an increase of 3.2C by 2100, these goals seem to be slipping out of reach.
“[We] still find ourselves in a situation where we are not doing nearly enough to save hundreds of millions of people from a miserable future,” said Erik Solheim, the UN environment chief, ahead of the upcoming Bonn conference.
One of the biggest resulting threats to cities around the world is the sea-level rise, caused by the expansion of water at higher temperatures and melting ice sheets on the north and south poles.
Scientists at the non-profit organization Climate Central estimate that 275 million people worldwide live in areas that will eventually be flooded at 3C of global warming.
Asian cities will be worst affected. The regional impact of these changes is highly uneven, with four out of five people affected living in Asia.
Although sea levels will not rise instantaneously, the calculated increases will be “locked in” at a temperature rise of 3C, meaning they will be irreversible even if warming eventually slows down.
Osaka, Japan is the first city to be drowned by global warming and 5.2 million people will be affected. Due to unseasonably late typhoons and relentless rain, Japan is already confronting the threat posed by climate change. A land is almost as big as that of the Netherlands – would disappear beneath the water threatening the local economy and almost a third of the wider region’s 19 million residents.
As a result of global sea-level rise, storm surges, and other factors, economists project that coastal flooding could put almost $1tn of Osaka’s assets at risk by the 2070s, according to the Union of Concerned Scientists. The costs of protecting cities from rising sea levels and storms are also likely to rise – as are the costs of repairing storm damage.
Like much of Japan, Osaka already has a network of seawalls and other coastal defenses in place to combat tsunami – although their effectiveness was disputed in the aftermath of the 2011 triple disaster.
Osaka city authorities are investing in other infrastructure to mitigate the effects of flooding, but public education is also vital, according to Toshikazu Nakaaki of the Osaka municipal government’s environment bureau.
“In the past, our response was focused on reducing the causes of global warming, but given that climate change is inevitable, according to the Intergovernmental Panel on Climate Change (IPCC), we are now discussing how to respond to the natural disasters that will follow,” Nakaaki said.
Alexandria, Egypt will be the second city to be drowned by global warming and 3 million people will be affected. On the Alexandria Corniche, waves slowly lap at a shoreline dotted with plastic chairs and umbrellas from the beachside cafes. Students perch on the steps of the imposing Alexandria library. But the same coastline that draws locals to its scenic vistas is threatening to slowly engulf the historic city as sea levels rise due to global warming.
The IPCC reported that Alexandria’s beaches would be submerged even with a 0.5-metre sea-level rise, while 8 million people would be displaced by flooding in Alexandria and the Nile Delta if no protective measures are taken. A 3C world threatens far greater damage than that.
Yet for many residents, there is little public information to connect the increasingly chaotic weather and floods with climate change. The vast majority of Alexandrians don’t have access to knowledge, and the government is not taking steps to raise awareness of this problem.
“Egypt spends 700m EGP [£30m] annually to protect the north coast,” said Dr. Magdy Allam, head of the Arab Environmental Experts Union, who was previously part of the Egyptian environment ministry.
Allam cited the Mohammed Ali seawall built in 1830 as a key protection, as well as the concrete blocks lining the shoreline designed to “detour flood water away from residential neighborhoods”. But critics say that this is far from enough given the scale of the problem.
“There are studies indicating that our city is one of many coastal human settlements around the world which will be partially submerged by 2070 if nothing is done,” said Ahmed Hassan, of the Save Alexandria Initiative, a group that works to raise awareness of the effects of climate change on the city.
Rio de Janeiro, Brazil is the third city to be drowned by global warming and 1.8 million people affected. Residents have plenty of reasons to fear global warming – even if they don’t quite know it. According to Climate Central, a temperature rise of 3C would cause flooding of not just Rio’s famous beaches such as Copacabana and its waterfront domestic airport, but also inland areas of the Barra de Tijuca neighborhood, where the Olympic Games were held. Barra is built around a network of heavily polluted lagoons that empty into the sea.
Storm surges recently destroyed hundreds of meters of beachfront pavement overlooking the Macumba beach, a popular surfing spot on Rio’s western fringes. In 2016, heavy waves in another storm surge felled an elevated, clifftop cycle path between Leblon beach and Barra de Tijuca which had not been built to survive such high seas, killing two people. The same year, Rio’s city government and the Federal University of Rio de Janeiro produced a study entitled Strategy for Adapting to Climate Change.
“The current challenge consists in deepening knowledge and monitoring of oceanic phenomena and the evolution of the seabed and coast,” a spokeswoman for the city’s Secretariat of the Environment said in an email.
An “adaption plan” for climate change produced with professors from the federal university suggested strategies to deal with vulnerabilities in areas such as transport, health, and housing. But so far little has been done.
The loss of Rio’s famous beaches would cost a lot of jobs. Some people know about global warming but they are unaware of the potential scale of the impact. Nobody takes it seriously yet.
Shanghai, China is the fourth city to be drowned by global warming and 17.5 million people affected. In 2012, a report from a team of UK and Dutch scientists declared Shanghai the most vulnerable major city in the world to serious flooding, based on factors such as numbers of people living close to the coastline, time needed to recover from flooding, and measures to prevent floodwater. According to Climate Central projections, 17.5 million people could be displaced by rising waters if global temperatures increase by 3C.
Projections show the vast majority of the city could eventually be submerged in water, including much of the downtown area, landmarks such as the Lujiazui skyline and the historical Bund, both airports, and the entirety of its outlying Chongming Island.
Since 2012, the government has been making steady inroads to tackle the threat, including building China’s largest deepwater drainage system beneath the Suzhou Creek waterway, made up of 15km of pipes to drain rainwater across a 58 sq km area. It has also rolled out a 40bn yuan (£5bn) River Flood Discharge project which will stretch for 120km between Lake
Taihu and the Huangpu river to try and mitigate the risk of the upstream lake flooding. Flood prevention walls are being built along the waterfront – in places so high the river is blocked from view – and 200km more are promised across the city’s outlying districts. Flood controls have been put in place along the famous Bund waterfront, where the walkway has been raised to help counter a flood risk, as well as a series of water controls and dams.
Miami, US is the fifth city to be drowned by global warming and 2.7 million people affected.
Few other cities in the world have as much to lose from rising sea levels as Miami, and the alarm bells sound ever louder with each successive “king tide” that overwhelms coastal defenses and sends knee-deep seawater coursing through downtown streets.
Locals consider this the “new normal” in the biggest city of Florida’s largest metropolitan area, which would simply cease to exist with a 3C temperature rise. Even at 2C, forecasts show almost the entire bottom third of Florida – the area south of Lake Okeechobee currently home to more than 7 million people – submerged, with grim projections for the rest of the state in a little more than half a century. In Miami-Dade County alone, almost $15bn of coastal property is at risk of flooding in just the next 15 years.
A sense of urgency is evident at city hall, where commissioners are asking voters to approve a “Miami Forever” bond in the November ballot that includes $192m for upgrading pump stations, improving drainage and raising sea walls.
“We have a really precious city that many people love and are willing to invest in right now, but it’s going to take some funds to protect it,” said Ken Russell, the city commission’s vice-chair.
In 2016, the city of Miami appointed sea-rise expert Jane Gilbert into the newly created role of chief resilience officer with instructions for a robust stormwater management plan that also looks at storm surges, such as that from Hurricane Irma in September which brought significant flooding to downtown Brickell and neighboring Coconut Grove.
Proposals include elevating roads and even abandoning neighborhoods to the water to protect others.
Flood maps were created using sea-level rise estimates from Climate Central and digital elevation data. Population estimates refer to urban agglomerations which comprise the built-up area of a city and the suburbs linked with it. Maps include OpenStreetMap data.
Temperature projections are based on University of Washington emissions modeling and UN warming estimates. Trajectories have been updated to match latest temperatures as recorded by the Met Office Hadley Centre.
As Josh Holder, Niko Kommenda, and Jonathan Watts reported to the Guardian.