Rising seas set to double coastal flooding by 2050: study

May 18, 2017 by Marlowe Hood
The tiny Indian Ocean atoll of the Maldives has a successful luxury tourism sector—but rising sea levels threaten the world's lowest-lying country, with coastal flooding predicted to double by 2050

Rising sea levels driven by global warming are on track to dramatically boost the frequency of coastal flooding worldwide by mid-century, especially in tropical regions, researchers said Thursday.

A 10-to-20 centimetre (four-to-eight inch) jump in the global ocean watermark by 2050—a conservative forecast—would double flood risk in high-latitude regions, they reported in the journal Scientific Reports.

Major cities along the North American seaboard such as Vancouver, Seattle, San Francisco and Los Angeles, along with the European Atlantic coast, would be highly exposed, they found.

But it would only take half as big a jump in ocean levels to double the number of serious flooding incidents in the tropics, including along highly populated river deltas in Asia and Africa.

Even at the low end of this sea rise spectrum, Mumbai, Kochi and Abidjan and many other cities would be significantly affected.

"We are 95 percent confident that an added 5-to-10 centimetres will more than double the frequency of flooding in the topics," lead author Sean Vitousek, a climate scientist at the University of Illinois at Chicago, told AFP.

Small island states, already vulnerable to flooding, would fare even worse, he added.

"An increase in flooding frequency with climate change will challenge the very existence and sustainability of these coastal communities across the globe."

The Indian metropolis of Mumbai is among many major cities across the globe threatened by rising sea levels which will see coastal flooding dramatically increase over the next 30 years, researchers say

Coastal flooding is caused by severe storms, and is made worse when large waves, storm surge and high tides converge.

Hurricane Sandy in the United States (2012), which caused tens of billions or dollars in damage, and Typhoon Haiyan in the Philippines (2013), which left more than 7,000 dead or missing, both saw devastating flooding.

Rising seas—caused by the expansion of warming ocean water and runoff from melting ice sheets and glaciers—is also a contributing factor.

Sea level 'wild card'

But up to now, global estimates of future have not adequately taken into account the role of waves, Vitousek said.

"Most of the data used in earlier studies comes from tidal gauge stations, which are in harbours and protected areas," he explained. "They record extreme tide and storm surges, but not waves."

To make up for the lack of observational data, Vitousek and his colleagues used computer modelling and a statistical method called extreme value theory.

"We asked the question: with waves factored in, how much sea level rise will it take to double the frequency of flooding?"

Los Angeles is one US coastal city which could face the fallout from rising sea levels, amid a feared doubling of the frequency of flooding by 2050, according to a study by climate scientists who also warn of risk to Europe's Atlantic coast

Not much, it turned out.

Sea levels are currently rising by three to four millimetres (0.10 to 0.15 inches) a year, but the pace has picked up by about 30 percent over the last decade.

It could accelerate even more as continent-sized ice blocs near the poles continue to shed mass, especially in Antarctica, which Vitousek described as the sea level "wild card."

If oceans go up 25 centimetres by mid-century, "flood levels that occur every 50 years in the tropics would be happening every year or more," he said.

The US National Oceanic and Atmospheric Administration (NOAA) predicts global average will rise by as much as 2.5 metres (98 inches) by 2100.

Global average temperatures have increased by one degree Celsius (1.6 degrees Fahrenheit) since the mid-19th century, with most of that happening in the last 70 years.

The 196-nation Paris Agreement, inked in 2015, calls for capping at well under 2C (3.6F), a goal described by climate scientists as extremely daunting.

Explore further: Increase in extreme sea levels could endanger European coastal communities

More information: Scientific Reports (2017). nature.com/articles/doi:10.1038/s41598-017-01362-7

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16 comments

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Shootist
2.1 / 5 (14) May 18, 2017
Better start walking, I tell you what . . . sea-level has been rising for 11,000 years.
antialias_physorg
4.4 / 5 (14) May 18, 2017
Better start walking

Better start saving up. Your tax dollars are going to pay for the disaster relief.
Shootist
2.3 / 5 (12) May 18, 2017
Better start walking

Better start saving up. Your tax dollars are going to pay for the disaster relief.


The same disaster relief we've been paying for 11,000. Put on your shoes and walk. There is no disaster when change takes decades. Alexandria has been buried for a millennium, cities on the Indian sub-continent for many thousands of years. Forests in the Engrish Channel... it's all the same. Put on your shoes and walk.

If you're actually worried about a warming climate . . . paint your roofs and roadways white and change the albedo of the planet. At least that is actual science.
jackmurdock
5 / 5 (7) May 18, 2017
There is no disaster when change takes decades.


Unless you're an ecosystem that can't just walk away because it took a million years to evolve. So yea, while us humans can just walk away, where shall we go when our natural world collapses around us due to environmental change at hyper-speeds?
Lino235
1.8 / 5 (15) May 18, 2017
"The sky is falling. The sky is falling!!"

"The oceans are rising. The oceans are rising!!!"
Benni
1.7 / 5 (12) May 18, 2017
Better start walking

Better start saving up. Your tax dollars are going to pay for the disaster relief.


The same disaster relief we've been paying for 11,000. Put on your shoes and walk. There is no disaster when change takes decades. Alexandria has been buried for a millennium, cities on the Indian sub-continent for many thousands of years. Forests in the Engrish Channel... it's all the same. Put on your shoes and walk.

If you're actually worried about a warming climate . . . paint your roofs and roadways white and change the albedo of the planet. At least that is actual science.


........but "science" is not what the foul mouthed name calling brigades are here for. They are are here for social networking, antialias_physorg simply being one of the same motley crew who can't make friends in the real world, so he comes here to find people like Stumpy to send his resume to.
aksdad
2.1 / 5 (11) May 18, 2017
These estimates are more than double the current rate of sea level rise. There is no evidence at all that the current rate is accelerating. Current rate is:

1.5 mm per year according to tide gauges
3.4 mm per year measured by satellite telemetry

In the next 33 years that works out to:

4.95 cm (1.95 inches) if the tide gauges are more accurate
11.22 cm (4.42 inches) if the satellite measurements are more accurate

Whichever is true, they are both far less than the so-called "conservative" forecast of 10 to 20cm. See here for current global and local sea level rise:

https://climate.n...a-level/
http://sealevel.colorado.edu/
https://tidesandc...nds.html

Where do they manufacture their forecasts? Computer models. Proving once again that the computer models aren't designed to mimic the natural world, they are crafted to create scary numbers.
Solon
1.8 / 5 (10) May 18, 2017
We also know that even in the inter-glacial warming periods that there can be cool periods that can be more devastating to an unprepared society than the slow, supposedly man made rate of warming. 1560-1610 for example, caused by solar activity, what we going to do about those periods?
1560-1610: Major advances by all glaciers.
greenonions1
4.3 / 5 (12) May 18, 2017
According to Aksdad's own reference - http://sealevel.colorado.edu/ - satellite data - cross checked against a network of tide gauges - shows the current rate of sea level rise to be 3.4 mm per year. Same reference also states
barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade.
So the numbers presented in this analysis are very reasonable.
tblakely1357
2.5 / 5 (8) May 19, 2017
Weird, I thought our coastlines were supposed to already be underwater.
Ojorf
4.1 / 5 (15) May 19, 2017
Shootist, Benni, aksdad, cantdrive, antig, tblakely, Solon, lino etc. (just about everyone consistently getting ratings < 2 ) your tenacity is almost admirable.
Time after time your claims are debunked, article after article the data turns against you, year after year the climate gets hotter, comment after comment your ratings get lower.
What a weird way to live.
ImTheOneWhoKnocks
3.6 / 5 (9) May 19, 2017
At first I was going to suggest that nobody is this stupid (looking at the peanut gallery rejects - Shootist, Benni, aksdad, cantdrive, antig, tblakely, Solon, lino etc.) and that perhaps this is yet another marketing campaign by big oil et al.

However, I have to remind myself just how stupid people are, particularly my fellow countrymen in these United States.
antialias_physorg
3.9 / 5 (8) May 19, 2017
What a weird way to live.

They must be getting paid or massive masochistic loners where this is their only form of human interaction.

Probably both.
Solon
2.3 / 5 (6) May 19, 2017
"Time after time your claims are debunked, article after article the data turns against you, year after year the climate gets hotter, comment after comment your ratings get lower."

As with most sites that have some kind of rating system for comments, those who do not believe the standard model fairy tales about black holes, dark matter, AGW etc, are always voted down by the majority, those who have been brainwashed by an education system that is stuck in the 19th century. Education should teach HOW to think, and not WHAT to think, and allow them to come to their own conclusions based on logic and reasoning.
It is also so obvious to those who can think independently and do their own research, that the mainstream media are all selling the same snake oil, and that anything science or research that goes against their agenda of even further dumbing down the masses, is omitted from the news or is twisted in such ways as to support mainstream views. This post will be a 1 no doubt.
greenonions1
4.1 / 5 (7) May 19, 2017
Solon - I was educated in the U.K. - think I got a pretty decent exposure to the ideas of critical thinking - and have certainly worked hard to nurture my critical thinking as an adult. I grew up very religious - and now understand very clearly that religion is the pinnacle of group think. I escaped. I live in the Bible belt - a deeply Conservative/religious part of the world. Anti science also runs very strong here. I think that people who have good flexible - critical thinking skills - will tend to support main stream ideas such as evolution, black holes, anthropogenic climate change etc. as those ideas were developed - by a system - that is based on research, data, multiple lines of evidence etc. It seems very clear to me that it is the narrow thinking folks who disagree with evolution etc. (ie are anti science).
Ojorf
4.3 / 5 (6) May 20, 2017
As with most sites that have some kind of rating system for comments, those who do not believe the standard model fairy tales about black holes, dark matter, AGW etc, are always voted down by the majority, those who have been brainwashed by an education system that is stuck in the 19th century. Education should teach HOW to think, and not WHAT to think, and allow them to come to their own conclusions based on logic and reasoning.


Well anyone who believes that the mainstream view (the simplest and best explanation that fits the data the closest and has repeatedly been challenged and verified by by rival scientists and groups) is without exception wrong (... fairy tales about black holes, dark matter, AGW etc.) has some soul searching to do.
You literally have to believe in a HUGE conspiracy and repression of information, coordinated across almost all scientific disciplines and including almost all the governments on earth.

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