With the greenland ice melt in the news, what can we do to adapt to a rising sea level, and how much will it actually be? First, the melting this summer was nothing unexpected. Last year Greenland had so much snow in 2017–8 that it actually gained ice rather than lost ice. So, now we have a warmer summer and it loses more than usual - not a big deal. This of course is the northern hemisphere summer which is why this news is about Greenland rather than Western Antarctica.

Mark Serreze, Director of the National Snow and Ice Data Center, interviewed by Discovery blog put it like this:

If you look at temperature records for the Arctic, what you see is natural climate variability superposed upon the general warming trend. Given that there is a lot of natural variability, I guess I’m not all that surprised. The last few summers have been somewhat cool, so we were due for a warm one. And here we are.

10 billion tons of meltwater poured off Greenland in a day — but are things as bad as the Twittersphere says?

None of this changes the projections for 2100 from the NOAA (National Oceanic and Atmospheric Administration in the US ) or IPCC. What matters long term isn’t the ice melt in South West Greenland anyway - it’s how fast the glaciers flow into the sea in North and North East Greenland. They are currently flowing very slowly because they are buttressed by the floating ice pack on the sea. In future if that melts away they will flow faster and contribute much more to the global sea level rise.

For details see my

If you are worried about the Arctic fires see my

This article is about the long term projections by the IPCC and NOAA, and what effects we can expect through to 2100 and about what we can do to cope with sea level rise (even at 1.5°C we will have some sea level rise continuing throughout the century due to the warmer conditions).

Note effects of Greenland ice melt are far less in Northern Europe than in the tropics and southern hemisphere. That’s because the mass of the ice is actually causing the Atlantic to hump up a bit close to Greenland and when it melts that water then spreads out causing the highest sea level rises in the southern hemisphere and equatorial regions. A bit paradoxically Northern Europe is most affected by Western Antarctica ice melt. See comment for details.

This is another article I'm writing to support people we help in the Facebook Doomsday Debunked group, that find us because they get scared, sometimes to the point of feeling suicidal about it, by such stories.

Do share this with your friends if you find it useful, as they may be panicking too.

Projected sea level rises - wide range from one foot to over a meter by 2100, even 2.5 meters for “business as usual” (which we are not on)

In the IPCC’s​ Fifth Assessment Report in 2013, there wasn’t enough research to properly asses the motion of glaciers in Greenland and West Antarctica. It is just hard to model. However they didn’t ignore the problem. They stated it clearly, saying the science wasn’t there yet to evaluate it and warning policy makers to allow for higher levels than their estimates for this reason.

In the 2018 IPCC report, however, chapter 3.3.9, they say that there has been significant progress since the IPCC AR5 report in 2013 to give them detailed models to assess. There are now many papers that do detailed sea level modeling also taking account of glaciers. So they were able to summarize these.

They said that there was little consensus between the studies but there were studies to review, and they could give a range of the values for future sea level rise.This is based on modeling as well as other ways to assess sea level rise.

At 2°C then they report that it is between 0.24 and 1.17 meters (5 - 95% confidence) and most likely between 0.24 and 1.17 meters (17 - 84% confidence). That’s still a huge range. Anything between less than a quarter of a meter rise by 2100 and over 1 meter.

However - that is what the literature says and their job is simply to summarize it. This is what they said:

“There is little consensus between the reported ranges of GMSL rise (Table 3.1). Projections vary in the range 0.26–0.77 m and 0.35–0.93 m for 1.5°C and 2°C respectively for the 17–84% confidence interval (0.20–0.99 m and 0.24–1.17 m for the 5–95% confidence interval).

Chapter 3 of the report, section 3.3.9 Sea Level, page 206

They do not cover a 3°C rise. We will have to wait for the next IPCC report for that which will be finalized in 2022. The NOAA report published in 2017 gives us an idea, its new “Extreme level” is 2.5 meters, however that’s not for 3 C, it is for “business as usual” or RCP 8.5 and it is their extreme scenario even for "business as usual". Their lower end of the range number for "business as susual" is 0.3 meters.

We are not on that, we are already well below "Business as usual" once you take into account the policies already in place and unconditional pledges.

For a 2°C rise they have a range of 0.2 to 0.5 meters, a bit lower than the 2018 IPCC report.

At sea level rise of 2 meters an estimated 187 million are affected by this 2011 report, but that's at "business as usual" and assuming no mitigation (such as sea walls).

Mitigation with sea walls - no we do not have to “give up the netherlands”!

The wealthier countries can mitigate sea level rises with sea walls, especially around cities, so only a few of those 187 million are affected by this.

When you hear people say

"We will have to give up the Netherlands"


To see this, consider the 300 meter high Nurek dam. It is an earth fill embankment just like the Netherlands

Nurek Dam Vakhsh River

Nurek Dam - Wikipedia

We are not going to get a sea level rise so high it can’t be solved by embankments in wealthy countries, if they choose to invest the resources needed to build them.

The Zuidplaspolder in Moordrecht is 6.76 meters below sea level Zuidplaspolder - Wikipedia

Some parts of Rotterdam are six meters below sea level or more, see topographical map here.

The famous dutch windmills to pump water from regions below sea level

That’s the reason for the numerous famous Dutch windmills, to pump the water out to keep the land dry at well below sea level. The thing is that the water from rainfall that flows through these areas in streams and ditches is below sea level, so something has to bring the water up to sea level to drain into the sea.

The windmills are no longer functional, are tourist attractions:

Credit: Henk Monster, CC BY 3.0. Dutch windmills used to pump dry swampy areas.

But in the nineteenth century they were the key to keeping the polders dry.

During World War II when the country ran out of fuel the historical windmills were the key to keeping Alblasserwaard from flooding.

This shows how all the windmills are part of a system to keep the water out.

Most polders are in the wealthier part of the country. So the inhabitants can afford the investment to keep the system functioning as sea level rises.

Those images and that summary is from this FAO article from 2010.

This video gives an account of how the Dutch were able to reclaim the sea bed and turn it into good agricultural land with more and more ambitious polders, and how they gained the experience to do this:

(click to watch on be)

What do they do with a one meter extra rise though?

But what can they do if the sea level rises another meter? Eventually it might need a big sea dike to keep out the sea - but then what about the big rivers of the Rhine and the Maas?

Rhine–Meuse–Scheldt delta - Wikipedia

The water flows through the Netherlands are complicated - it has tributaries such as the Rhine and the Maas- but it also has distributaries, the country is basically a big delta fed by multiple rivers that then merge and split again into more rivers that flow into the sea, with the whole thing managed by vast works of hydraulic engineering dating back centuries.

It’s one thing pumping out the polders, but it’s an altogether bigger project to pump an entire river up one meter?

Well the thing is that the highest sea levels are only during storm surges and very high tides. So - what you need to do is to stop the sea coming in during a big surge - and also have ways to back up the water from the river until they go out again.

The cities could be evacuated of course, but protection costs much less than evacuating. The idea engineers are looking at is giving the water space. Rotterdam has giant flood gates to keep out the sea at the highest tides:

Then as the tides drop the water is let out and boats can go in and out as normal:

This is one of the engineering marvels of Europe, designed by the architect Wim Quist. It’s the size of two Eiffel towers toppled over and has ball joints at each side that are 9 m (30 feet) in diameter and weigh 680 tns

It is already high enough for extreme sea level rises, but they are going to add an extra two feet to it.

The computers monitor sea level rises and open it and close it.

A new idea is the “room for water”. When the gates are closed then

“lakes, gardens, basketball courts, open-air theatres, parks and plazas could also double as enormous reservoirs for when the seas and rivers spill over.”

The Dutch solution to rising seas

See also video at the end of that page and interview here Living on Earth: Dikes, Floods and Adaptation

See also

(click to watch on be)

Only at the highest tides to start with

It will make a difference to fields, roads and houses that are only a little way above sea level already. The sea can't travel uphill, and at low tide will drain out again.

To start with it would happen only during the very highest king tides which are once a year or so, and after storm surges where the wind blows sea into humps against the land, and during hurricanes and typhoons where the low pressure can cause sea level rise.

Then as global sea levels rise it happens more often. However, it's not like the popular imagination that suddenly one year you find that e.g. Miami is permanently under water from then on. Miami is already affected by storm surges and as the sea rises this happens more often.

Only the lowest parts of the country are affected. For instance with Bangladesh it's just the delta where it meets the sea or around the river banks where the river backs up due to the sea level rise as well as river flooding because of the Himalayan glaciers which are melting more than usual in a warmer world.

For coastal areas outside of cities, then it's a matter of a decision about whether it is better to have a hard barrier or a kind of softer barrier. If you have a hard barrier it's fighting against nature and it may not be so ecologically valuable. Any beaches beyond it may be washed away.

Nowadays they tend to allow the sea in at least to some extent, to create natural salt marshes and mix those with lower barriers, the "barriers and sponges" approach.Salt marshes are also valuable habitats ecologically and they take up a lot of CO2.

Applying the ingenious dutch ideas to the US and around the world

There are many other ingenious Dutch ideas which they are exporting to the US and other places. With their experience of living with the sea higher than their country for centuries they already know how to deal with conditions that other cities are beginning to face for the first time. This is what is likely to be needed for New York, a new project under construction that uses some of their ideas such as a variety of barriers, and storage for the water:

Project to ring lower Manhattan with 16 kilometers of protection from storms - with various barriers as well as floodwater runoff and storage areas. Credit: BIG-Bjarke Ingels Group. Dutch Masters: The Netherlands exports flood-control expertise

Example of Bangladesh

The system of dikes and the engineering of the Netherlands is expensive to build. Bangladesh is another country that has large areas consisting of the vast Ganges delta. Fertile land but very low, vulnerable to sea level rise

Ganges delta - Wikipedia

The poorer countries are more likely to solve it by internal migration. An estimate for Bangladesh finds that 0.9 million people of its population could be displaced by direct inundation by 2050 and 2.1 million by 2100, almost all of this in the southern half of the country.

As well as sea level rise - about half of those in the urban slums were displaced by river bank erosion and river flooding. This is because of the way rainfall increases and becomes more erratic with climate change, and also the melting Himalayan glaciers affecting river flows. They also are affected by stronger cyclones in a warming world which damages infrastructure.

Every day 1000 to 2000 people migrate to Bangladesh’s capital Dhaka - and almost all of them when asked say they migrated because of the changing environment.

However Bangladesh is also spending considerable amounts on climate mitigation and adaptation. It spends $1 billion per year on climate change adaptation - a lot for a poorer country. That is 6 to 7 percent of its annual budget.

Three quarters of that money comes directly from the government, only a quarter from international donors.

The average European emits as much carbon in 11 days as a Bangladeshi in a year. Yet it is the average Bangladeshi who is footing a lot of the bill for our carbon dioxide. For poorer Bangladeshis, the climate change bill per year often reaches as high as double their annual income, and poorer communities there are picking up crippling debts. So the costs of climate change are already hitting Bangladesh hard

Bangladesh would need about $3 billion a year by 2030 for climate adaptation, and $2 billion to mitigate against effects of climate change. So far the average domestic and external investment combined is $1.3 billion leaving a $1.7 billion funding gap. However Bangladesh is seen as an example of a country that is doing a lot to combat climate change.

The higher income countries agreed to mobilize $100 billion a year worldwide in climate finance by 2020 to help support low and middle income countries become climate resilient and transform to clean energy. So far though the amount of finance available is far below this. Oxfam estimate $16-21 billion

These funds of course benefit everyone by helping us remain within a world with lower emissions worldwide and as well as creating a world with resilient countries which can contribute to the world rather than need assistance in emergency support as the climate impacts hit them later on.

It is hard for Bangladesh to reduce its emissions since its per capita emissions are already very low, 0.46 metric tons per capita per year, and it is industrializing and it’s low income. However it’s INDC (Intended Nationally Determined Contributions) has:

  • an unconditional contribution to reduce GHG emission by 5% from business as usual [BAU] levels by 2030 in the power, transport and industry sectors
  • a conditional 15% reduction in GHG emissions from BAU levels by 2030 in the power, transport and industry sectors;”
  • a number of further mitigation actions in other sectors which it intends to achieve subject to the provision of additional international resources (conditional).

Because of their similar situation, Bangladesh has support from the Netherlands in several projects, notably the Bangladesh Delta Plan 2100 (BDP 2100) by knowledge transfer, and support of the institutions responsible for delta planning.

It will be financed internally up to a level of 2.5 per cent of GDP per annum by 2030 of which, 2.0 per cent of GDP would be from public funding and 0.5 per cent would be from the private sector.

For the river flooding, one innovation in Bangladesh is to make floating farms that rise as the river levels rise.

(click to watch on be)

They can also use the sallt water to keep shrimp and crabs.

(click to watch on be)

Rebecca Eldon, who researched into Bangladesh’s NDC for her thesis, puts it like this:

Since my first visit to Bangladesh, the country has stood out to me as one of the most unique places in the world. There is incredible beauty, seen both in the population’s love for art and culture, and in the deeply rooted kindness and hospitality people show to one another. At the same time there is heart-breaking poverty, which is exacerbated as Bangladeshis experience some of the most severe impacts of climate change in the world.

Researching Bangladesh’s Nationally Determined Contribution | International Centre for Climate Change and Development (ICCCAD)

Example of Florida

Florida is especially hard hit by sea level rise because it is built on foundations of limestone, a porous rock. There is nothing they can do to keep out the highest "King tides" and storm surges, except build up.

At 1.5 C the most likely increase is around 0.3 meters by 2100. But it coudl be more. In Florida it would be more like 0.5 meters because the sea level rises faster than the average sea level there.

In a warmer world if we get as far as a 1.8 meter sea level rise, then according to one study, there would likely be 2.5 million Florida residents migrate away, most from Miami. 250,000 would likely leave San Francisco and nearby areas. Meanwhile Texas could see an additional 1.5 million immigrants, just because of the sea level rise.

'We're moving to higher ground': America's era of climate mass migration is here

According to Climate Central who specialize in detailed sea level rise modeling a twelve foot rise would look like this:

It is an interactive graphic, this is half of each

And original:

It is built on limestone so you can’t keep out the sea with a sea wall. However the sea is tidal of course. This is only for the very highest tides. Either storm surges or a King tide.

These images are for the new “Extreme” level of sea level rise added by NOAA to its projections in 2017, corresponding to the unlikely but now increasingly plausible possibility that some parts of the Antarctic ice sheet may begin to collapse much sooner than scientists previously thought. It would mean a faster sea level rise, by 8 feet by 2100 or a bit over an inch a year. Currently it is rising at about a tenth of an inch a year. But this is for "Business as usual" and we are well below that. More details here

However it has knock on effects. Florida has an extensive drainage system of canals that eventually ends up in the sea, and the water is kept artificially higher than sea level to keep it flowing into the sea. If the sea level rises an extra six inches, a plausible rise within decades, then about half of South Florida’s flood control capacity would be crippled. It’s already risen eight inches in the twentieth century.

Then to make it worse, the worst hurricanes are expected to get worse in a warming world which leads to more flooding, and if that’s associated with a high sea level, then the water can’t drain so the flooding is worse.

Even if we stop emissions right away then the ice will continue to melt, though not so fast, and Florida will have to adapt to higher sea levels.

These levels are nothing like the ones during the last ice age though, when the sea level was probably 6 to 9 meters higher. This is what Florida looked back then - you can actually trace out the past sea level from various fossil shell beds and other evidence.

Florida's Geological History The red line shows the location of Cody Scarp, an indicator of the past sea level during the ice ages.

Cody Scarp which was the ancient shoreline. credit Suwannee River Hydrologic Observatory, Santa Fe Maps Florida's Geological History -- Figure 9. The position of the Cody Scarp

We aren’t going to get that far by 2100, but in a warmer world if we get as far as a 1.8 meter sea level rise, then according to one study, there would likely be 2.5 million Florida residents migrate away, most from Miami. 250,000 would likely leave San Francisco and nearby areas. Meanwhile Texas could see an additional 1.5 million immigrants, just because of the sea level rise. 'We're moving to higher ground': America's era of climate mass migration is here

The e Southeast Florida Regional Climate Change Compact was formed to look into ways to mitigate this in 2010.

By 2100 then residents of South Florida may end up living on stilts much like the inhabitants of Venice. That’s for a 1.5 meters rise.

The Compact predicts the sea will rise 31 to 61 inches by 2100. If the sea rises 61 inches, much of South Florida will be under water. People will be living in buildings on stilts and using water-based transportation. With decades to adapt, some people may find living atop water a viable lifestyle.

Here are some of the possible effects:

  • Coastal inundation of inland areas
  • Increased frequency of flooding in vulnerable coastal areas
  • Increased flooding in interior areas because the region’s stormwater infrastructure – gravity drainage systems and the region’s canals — will become less effective
  • Saltwater intrusion into the aquifer and local water supply wells
  • Contamination of the land and ocean with pollutants and debris and hazardous materials released by flooding
  • People will move away
  • Decrease in property values and tax base
  • Higher insurance costs
  • Loss of services and impaired access to infrastructure

Interview about it here with two scientists, the first is Susy Torriente, chief resilience officer and assistant city manager for the city of Miami Beach talking about what they are doing in Miami.

They are doing sea walls as flood barriers, a pump based system, and raising roads.

Their main point is that we still have time to find solutions. A huge challenge but one they need to move through as a nation.

See also

The U.S. Army Corps of Engineers, by the 2016 Water Resources Development Act have to study 10,000 miles of coastline along the south Atlantic and Gulf Coast

“to identify the risks and vulnerabilities of those areas to increased hurricane and storm damage as a result of sea level rise.”
Read more here: here

A key part of all this is the multibillion dollar Everglades Restoration project. this will help keep the Everglades ecosystem, by increasing the flow of the water, but as they say in the 2015 report, this will allow nature to respond in a more gradual fashion, rather than the salt rapidly moving into the slough features of the Everglades, the increased flow will give the freshwater head to allow nature to retreat back from the rising sea and make new organic soil as it does so.

Regional Impacts of Climate Change and Issues for Stormwater Management - South East Florida (2015)

It costs $10.5 billion with a 35+ year timeline and is the key to Florida’s successful climate adaptation.

(click to watch on be)

Here are some recent stories in the Miami Herald about some of the challenges and how they are meeting them.

Check sea level rise for your city

You are not going to be affected directly if you live several meters above sea level. Even the NOAA extreme level by 2100 is only 2.5 meters. It is larger in some areas because sea level rise is uneven e.g. larger in tropical areas, Florida is one of worst affected, local sea level rise 4 meters.

NOAA tool for the US

NOAA is the National Oceanic and Atmospheric Administration (US). They are experts on sea level rise and global temperature measurements.

If you live anywhere along the coast of the US you can check the sea level rise locally for the NOAA five scenarios from intermediate low through to extreme.

Map here

Sea Level Rise and Coastal Flooding Impacts

The five levels for the NOAA are 0.3 m, 0.5 m, 1.0 m, 1.5 m, 2.0 m and the new “Extreme” level of 2.5m.

The chances of reaching them for each pathway are shown in this table from their Technical report GLOBAL AND REGIONAL SEA LEVEL RISE SCENARIOS FOR THE UNITED STATES published January 2017:

There RCP 2.6 is the 1.5 °C path we are aiming for. 94% certain it remains at low (0.3 m). RCP 4.5 is 2.4 °C and we have a pretty good chance of that, it’s only a bit below the 3 °C we are already on and many countries including China are expected to ramp up their pledges in 2020. RCP 8.5 is “business as usual” and we are already well below that one.

  • RCP 2.6: reach 1.5 °C, ~490 ppm CO2
  • RCP 4.5: reach 2.4 °C, ~650 ppm CO2
  • RCP 6: reach 3 °C,~850 ppm CO2
    (with existing policies and unconditional pledges we are headed for around 3 °C).
  • RCP 8.5: reach 4.9 °C, ~1370 ppm CO2, “Business as usual”.
    (We are already well within this one, by existing policies alone)

It is a good tool but sadly only available for the US. There is a bit of a learning curve for it. It’s explained here

Surging seas map - over estimates future rises for your city

You can look up the sea level rise in the Surging Sea map. But this over estimates the effects:

Mapping Choices: Which sea level will we lock in?

There are many dramatic videos on this page

(click to watch on be)

Global Cities at Risk from Sea Level Rise: Google Earth Video

They do not mention it in that video but do in some of the others on that page and do if you se the tool itself - that these are for some time between 200 to 2000 years from now. We may well use carbon capture and storage or carbon capture and utilization or extensive reversing of desertification and new forests over those timescales.

Australia map

There is a good map to explore for Australia here. You can choose to show how high it would rise based on today's tides, and based on the highest tides for your location and they do it based on individual tide ranges for each coastal location. The Medium scenario is the one we are on now, roughly (it’s between 2.4 °C, and 3°C while we are on 3°C). The “low” level is the 1.5 °C one. But bear in mind as for the NOAA then we do not know for sure what the level is for each temperature increase, these are the best guesses so far.

Coastal Risk Australia

If you are worried about a recent article about the sea level rise in Australia since the ice age - that was 125 meters, 50 times the NOAA extreme level of 2.5 meters.

For the bigger picture:

See also, the IPBES report and their solution involving a high percentage of sociologists and economists:

I wrote that based on the summary for policy makers and the press conference. The draft chapters are now available online.

This article was originally posted in my Quora blog "Debunking Doomsday" as:

Doomsday Debunked

Seven tips for dealing with doomsday fears

If you are scared: Seven tips for dealing with doomsday fears which also talks about health professionals and how they can help.

If in the middle of a panic attack, see

Useful links to bookmark

Tip, bookmark those links to search for debunks more easily. Here is a screenshot of my bookmarks

Facebook support group

Facebook group Doomsday Debunked has been set up to help anyone who is scared by these fake doomsdays.

Wiki Doomsday debunked wiki

If you need help

Do message me on Quora or PM me on Facebook if you need help.

There are many others in the group who are available to support scared people via PM and who can also debunk fake Doomsday “news” for you if you get scared of a story and are not sure if it is true. See our debunkers list

If you are suicidal don’t forget there’s always help a phone call away with the List of suicide crisis lines - Wikipedia

Our petitions