Sea level rise of 1 meter within 100 years

Jan 08, 2009
The curve shows the sea level from the year 200 to the year 2100. The future rise in sea level of 1 m is calculated from global warming of 3 degrees in this century. The dotted line indicates the UN Intergovernmental Panel on Climate Change's prediction. The blue shade indicates the calculations' degree of uncertainty. Credit: Aslak Grinsted, Niels Bohr Institutet

New research indicates that the ocean could rise in the next 100 years to a meter higher than the current sea level - which is three times higher than predictions from the UN's Intergovernmental Panel on Climate Change, IPCC. The groundbreaking new results from an international collaboration between researchers from the Niels Bohr Institute at the University of Copenhagen, England and Finland are published in the scientific journal Climate Dynamics.

According to the UN's Intergovernmental Panel on Climate Change the global climate in the coming century will be 2-4 degrees warmer than today, but the ocean is much slower to warm up than the air and the large ice sheets on Greenland and Antarctica are also slower to melt. The great uncertainty in the calculation of the future rise in the sea level lies in the uncertainty over how quickly the ice sheets on land will melt and flow out to sea. The model predictions of the melting of the ice sheets are the basis for the Intergovernmental Panel on Climate Change's predictions for the rise in sea level are not capable of showing the rapid changes observed in recent years. The new research has therefore taken a different approach.

Looking at the direct correlation

"Instead of making calculations based on what one believes will happen with the melting of the ice sheets we have made calculations based on what has actually happened in the past. We have looked at the direct relationship between the global temperature and the sea level 2000 years into the past", explains Aslak Grinsted, who is a geophysicist at the Centre for Ice and Climate at the Niels Bohr Institute at the University of Copenhagen.

With the help of annual growth rings of trees and analysis from ice core borings researchers have been able to calculate the temperature for the global climate 2000 years back in time. For around 300 years the sea level has been closely observed in several places around the world and in addition to that there is historical knowledge of the sea level of the past in different places in the world.

By linking the two sets of information together Aslak Grinsted could see the relationship between temperature and sea level. For example, in the Middle Ages around 12th century there was a warm period where the sea level was approximately 20 cm higher than today and in the 18th century there was the 'little ice age', where the sea level was approximately 25 cm lower than it is today.

A rise in sea level in the future as in the past

Assuming that the climate in the coming century will be three degrees warmer, the new model predictions indicate that the ocean will rise between 0,9 and 1,3 meters. To rise so much so quickly means that the ice sheets will melt much faster than previously believed. But it has already been observed that the ice sheets react quicker to increases in temperature than experts thought just a few years ago. And studies from the ice age show that ice sheets can melt quickly. When the ice age ended 11.700 years ago, the ice sheets melted so quickly that sea level rose 11 millimeters per year - equivalent to a meter in 100 years. In the current situation with global warming, Aslak Grinsted believes, that the sea level will rise with the same speed - that is to say a meter in the span of the next 100 years.

Source: University of Copenhagen

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User comments : 15

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MikeB
2.4 / 5 (16) Jan 08, 2009
OK Physorg, I think that this article is in direct disobedience to Al Gore. Please, in the future call Mr. Gore first before you consider publishing this type of nonsense, Everyone knows that the sea level will rise between twenty and eighty feet by 2050. Please, please tell everyone the truth. If you don't, you will be responsible for all the drownings worldwide.
Thanking you in advance for calling Al Gore first,
Mike
Velanarris
3.2 / 5 (11) Jan 08, 2009
I thought the 1 meter rise was already knocked down, how current is this article?
gmurphy
3.5 / 5 (8) Jan 08, 2009
this is good work, it's an intelligent approach to the complex problem of predicting climate change. This has further potential for enhancing the accuracy and relevance of climate models. Then again, it could be part of the conspiracy led by Al Gore, better put on those tinfoil hats fellas...
GrayMouser
2.2 / 5 (11) Jan 08, 2009
Remember, what is happening now is due to human influence so looking at historical events is not relevant.

On the other hand, if you accept historical events for this, why not accept historical reading of CO2 levels many times higher than now with out runaway warming?
MikeB
2.4 / 5 (11) Jan 08, 2009
Gray,
For the love of all that you hold admirable, please do not try to make sense out of any study you read on physorg. Don't you realize that the only thing that matters is that we must follow Dr. Gore. We must believe with our hearts, NOT our minds. You are NOT a scientist. They are saying one meter, ONE METER of sea level rise! That's about three feet. When Dr. Gore finds out about this, this... ridiculous claim he will set these physorg people straight! If... IF they change their ways and begin to publish the truth IMMEDIATELY, Dr. Gore might be able to find a small place for them in the new world order of peace, habitability and oneness with nature that all right-thinking people strive for, and hold deeply in their hearts.
Hug a tree today!
Mike :)
RAL
2.8 / 5 (11) Jan 09, 2009
Give me a few minutes and a spreadsheet and I'll bet I can project a rise double this. With the proper alarmist projections I should have an inside track in the next funding cycle and be able to buy a bigger spreadsheet to make the oceans rise even faster -- on paper.
SteveS
3.3 / 5 (4) Jan 09, 2009
"Looking at the direct correlation"

Correlation does not imply causation. Without knowing the mechanism they cannot make reliable predictions.

Models can be used to test possible mechanisms and past data used to test the models. This appears to be the method used by the IPCC.

I know I'm opening myself up to a world of abuse by appearing to praise models or anything originating from the IPCC, but this is the way science works. Observe, theorise, test, and refine.

out7x
2.5 / 5 (10) Jan 09, 2009
This article is pure nonsense. An embarrassment to science.
BenD
3.1 / 5 (11) Jan 09, 2009
Gentlemen, please. This isn't that bad an article. It has a genuine bit of science with a reasonable methodology of observation and correlation. SteveS, the relationship does appear valid, as temperature directly affects both the main drivers of sea level, thermal expansion and ice melt.

Now, the problems: It is not a reasonable result. You are saying that sea level will rise at the same rate as at the end of an ice age. That violates common sense, so that will require a lot of corroberating evidence. Then, they will have to show that the correlation between temp and sea level is linear and not Arrhenius shaped (my gut tells me that it should be the latter). This goes to show that extrapolation is almost always a bad idea that gives unsupportable results.

Furthermore, they explain that this is based on a 3 degrees (C?) rise in temperatures. This temperature rise is utterly unsubstantiated in facts. There is no evidence for it (climate models, which are extrapolations themselves, cannot be evidence. Their results are interesting, but provide possibilities only.)

Alright, maybe it is that bad an article.
Velanarris
3 / 5 (10) Jan 09, 2009
They also completely ignore the atmospheric potential of water vapor content, which the IPCC took into account in their models (surprisingly), and the ambient precipitation that follows taken up by the remaining ice and glaciers.

It's almost as though this research assumed x amount of ice means x amount of sea level rise, and ignored all other factors that are potentially at play.

It's simply a poor model.
lengould100
1 / 5 (2) Jan 09, 2009
Geniuses at work again, I see.
lengould100
2.4 / 5 (5) Jan 09, 2009
[knock knock]

Are you in, genius?
Are you in, competent?
Are you in, sufferable?

[from the classic Bugs Bunny / Roadrunner cartoons ;
Nartoon
1 / 5 (3) Jan 09, 2009
I could be mistaken, but didn't the last ice age cover half of North America and Europe with ice 3 km thick. I haven't looked outside for a few minutes, but I don't think it's quite that thick yet.
MikeB
3 / 5 (2) Jan 10, 2009
Uhhhh... who said anything about an ice age?
Velanarris
not rated yet Jan 12, 2009
Uhhhh... who said anything about an ice age?
We'd have to currently be in one in order to have a sea level rise similar to that predicted by the above study if I'm reading what Nartoon said correctly.

Realistically you wouldn't though. If there was a permanent and constant 3 degree rise 1 meter is reasonable.

I don't see a 3 degree rise by 2100 happening, neither do even the most bold of agw predictions. I think the average noted rise now a days is 0.5 degrees C with the bigger ones being around 1 full degree C.

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