Sea level has risen globally by around 20 cm from 1901 to 2010, at an average rate of 1.7 mm per year. The rate has increased over this period and is currently 3.2 mm per year. It is estimated that around 70 per cent of sea level rise from 1970 to 2005 can be attributed to human activities. At present the largest contribution is caused by thermal expansion of the world’s oceans – the volume of water increasing simply due to warming (40 per cent of the increase from 1993 to 2015). The rest is from the better-known losses of land ice from glaciers (25 per cent) and the Greenland and Antarctic ice sheets (20 per cent), along with transfer from land water sources such as groundwater and snow (15 per cent), with the ice sheet contributions increasing during this period. Data from Dr Tamsin Edwards’ report cited below.
Climate Central just completed a novel analysis of worldwide exposure to sea level rise and coastal flooding. They found that 147 to 216 million people live on land that will be below sea level or regular flood levels by the end of the century, assuming emissions of heat-trapping gases continue on their current trend.
Only countries with a total population of over 1 million were included in the Climate Central analysis. This means that most island nations do not appear in their tables, which are copied below:
These tables appear to grade countries according to the size of their populations and what proportion of that population is at risk from coastal flooding. Thus, China would have the greatest number of their inhabitants affected by sea level rise but, in terms of the percentage of their population as a whole, this is only 4%. Conversely, the Netherlands have a smaller number of their people at risk from coastal inundation, compared with China, but this represents almost half (47%) of their total population, putting them at the top of the table, percentage-wise. However, Vietnam comes second in the list, however the calculation is done, and Japan comes third and fourth. So many Asian countries are particularly at risk.
Chapter 1 (Figure 15) of my book features some of the maps produced by National Geographic Creative. These show the new coastlines if all of the ice caps were to melt. From these maps, I personally would want to place countries like Bangladesh, the Netherlands, Denmark, Cambodia, Japan, much of the eastern coast of USA (especially Florida), southern Thailand, much of Indonesia, most of the Pacific and Indian ocean island nations, very close to the top of the list. But then, I am looking at them in terms of territory lost, rather than the numbers of people displaced. It would be interesting to see these tables showing countries rated according to how much territory they would lose.
Another factor that needs to be looked at is the huge numbers of major cities of the world which would go under water. They include:
Alexandria, Amsterdam, Auckland, Baghdad, Bangkok, Beijing, Berlin, Bissau, Boston, Brussels, Buenos Aires, Cancun, Copenhagen, Dakar, Dar es Salaam, Dhaka, Doha, Freetown, Georgetown, Helsinki, Ho Chi Minh City, Hong Kong, Honolulu, Houston, Jakarta, Kolkata, Lagos, Lisbon, London, Manila, Maputo, Melbourne, Miami, Montevideo, Montreal, New Orleans, New York, Phnom Penh, Rangoon, Riga, Rio de Janeiro, Rome, St. Petersburg, Shanghai, Singapore, Stockholm, Tallinn, Tampa, Tokyo, Vancouver, Venice.
A recent article in The Guardian (5.10.18) focuses just on what is happening in the cities of the world, some of which are sinking (some due to the weight of the tall buildings that have been built there eg Bangkok), as well as sea-level rise and other reasons, such as the geology of the area. Sinking cities include London, Shanghai, Jakarta and Houston. A report from Christian Aid also focuses on the cities that are sinking and describes Jakarta, which is said to be sinking by 25 cm a year, largely because of groundwater extraction. Houston is sinking as the oil wells beneath it are depleted. The Christian Aid study focused on eight of the major cities of the world. For full details of the situation facing Jakarta (Indonesia), see the following report:
Slums in Jakarta, the world’s fastest sinking city
Many cities have been built in coastal areas and near major rivers. This makes them vulnerable, not only to sea level rise but also to storm surges. Amitav Ghosh has discussed the situation regarding Asian cities like Mumbai and Kolkata in his book “The Great Derangement: Climate Change and the Unthinkable” (2016, published by University of Chicago Press). He comments on Asia’s late entry into the process of industrialisation and believes that, due to the numbers of people involved, this has brought the climate crisis to a head. He surmises that “The brute fact is that no strategy can work globally unless it works in Asia and is adopted by large numbers of Asians.”
And to add to these reports, there was a recent piece in The Times, warning about the effects of rising sea levels in Scotland. It can be found at:
According to the Times report, scores of coastal towns, Prestwick airport and Faslane are all at risk, although Scotlandas a whole is rising rather than sinking.
And another recent report from Molly Rubin in Quartz, reports on measures that are being taken in New York to prevent another storm surge like the one that occurred with Hurricane Sandy in 2012. It involves a system of underwater gates, which can be raised and lowered to block surges. The UK and Netherlands use similar systems: the Thames Barrier in London and Maeslantkering in Rotterdam.
The US clearly has the money to introduce such systems, which developing countries do not have.
The Thames Barrier in London
And another recent article, this time in The Guardian (3rd November 2017) focuses on Lincolnshire and outlines how much farmland and coastal regions will go under water with 3 degrees of global warming, changing the coastline for ever.
According to The Guardian, the county is a major recipient of the government’s six-year £2.5bn programme to strengthen sea and flood barriers in England. This is done with a mix of soft defences (sandy shores, mudflats and wetlands to absorb wave impact) by the coast along with hard defences (concrete walls) further inland. The authorities replenish eroded beaches such as Skegness each year with 350,000 cubic metres of of sand. Earlier this year, two new flood-alleviation reservoirs were completed in Louth and Horncastle. A public inquiry has also been held for a £100m flood barrier scheme in Boston.
This is another example of a developed country being able financially to deal with the effects of sea level rise.
A coastal region of the flat Lincolnshire countryside
A 2015 report in The Guardian states that some UK coastal communities could be facing up to 6 metres of sea level rise, even if it is possible to keep global warming below 2 degees.
I have just come across a Government-commissioned report on the impact of sea level rise on the UK. The 39-page report “Future of the Sea:Current and Future Impacts of sea level rise on the UK” has been written by Dr Tamsin Edwards and published in August 2017. It can be found at:
Below is a copy of the executive summary of the report:
“Sea level rise increases coastal flooding and erosion, creating risks for UK
infrastructure, communities, businesses and natural capital. Coastal flooding is one of the top four priority risks for the UK Government, and estimated annual damages are £540 million. Sea level rise projections for the 21st century are very uncertain, generally ranging from around 25 cm to around 1 m (depending on greenhouse gas emissions and ranges of modelling uncertainties), with a few estimates consistent with 1.5–2.5 m.
Uncertainty in the Antarctic ice sheet response to climate change is the largest driver of uncertainty concerning sea level rise during this century. The first study to estimate probabilities of sea level rise from rapid Antarctic ice losses, co-led by the UK, strengthens evidence for the lower end: median total sea level rise of around 70 cm, implying estimated annual damages of £1.3–1.5 billion in the 2080s under current adaptation. A high-profile 2016 study has mean Antarctic estimates consistent with 2 m total sea level rise, but with large uncertainties and no consensus on their reliability. The UK is in a strong position to reduce this uncertainty due to world-leading expertise.
The 2017 Climate Change Risk Assessment is wide-ranging, but the underlying research may systematically underestimate coastal flood risks. Better understanding of coastal processes, correlated risks (floods and impacts connected across space, time, business, sectors or nations), indirect impacts (such as disruption), infrastructure exposure and vulnerability, and the impacts of population and demographic changes on risk, would increase confidence that risks are sufficiently assessed.
Risks can be reduced with sea defences, coastline realignment, land-use planning,
forecasting, and property-level protection. However, not all risks can be offset, increasingly so with sea level rise and population increase.
Response options for risk management include improving data collection, understanding, and uptake. Exposure and vulnerability data are sparse in several areas such as infrastructure and wellbeing, and the co-benefits and negative impacts of adaptation are not well-quantified. Use of existing evidence on risk management is limited in key sectors across individuals, infrastructure, businesses and local authorities.”
Following on from this is a report in The Guardian , which warns that 12 of Britain’s 19 nuclear sites are on land at risk of coastal flooding and erosion due to climate change. The information is from a government document obtained under the Freedom of Information Act in 2012. Among the sites at risk is Hinckley Point in Somerset, which is one of eight sites around the UK which has been proposed for the building of new nuclear power stations. See:
Among the list of countries at risk of coastal flooding at the beginning of the article is Thailand (7th on list 1 and 3rd on list 2). A new report about this country and its capital, Bangkok, can be found in the Financial Times and at:
In the South China Morning Post, the heading is given:
Bangkok is sinking. How will Thailand’s capital cope when flooding disaster strikes again?
With the weight of skyscrapers contributing to the city’s gradual descent into water, Bangkok has become a victim of its own frenetic development. Bangkok is a sprawling city of more than 10 million and is under siege from the environment, with dire forecasts warning it could be partially submerged in just over a decade.
Bangkok, built on once-marshy land about 1.5 metres (five feet) above sea level, is projected to be one of the world’s hardest hit urban areas. “Nearly 40 per cent” of Bangkok will be inundated by as early as 2030 due to extreme rainfall and changes in weather patterns, according to a World Bank report. Currently, the capital “is sinking one to two centimetres a year and there is a risk of massive flooding in the near future,” said Tara Buakamsri of Greenpeace.
Flooding in Bangkok
Other Asian cities are also sinking, for example Jakarta and Manila.
Indonesian President, Joko Widodo, has announced that the country will relocate its capital Jakarta to the island of Borneo. Taking on concerns of overcrowding, pollution, and income disparity, the move also hopes to address issues of extreme land subsidence. The new city would be built over 800 miles away from the current capital.