New study finds sea level rose 2.4 mm/year between 2005 and 2011

Jun 03, 2013 by Bob Yirka report
Global mean sea level (GMSL) change. a, GMSL change observed by the TOPEX/Poseidon and Jason-1/2 satellite altimeters during the period 1993–2012. b, The same as in a, but for the most recent 7-year period (January 2005–December 2011). Credit: (c) NPG, Nature Geoscience (2013) doi:10.1038/ngeo1829

(Phys.org) —A new study conducted by researchers at the University of Texas' Center for Space Research, indicates that sea level rise between 2005 and 2011 was due primarily to glacial and polar ice shelf melting. In their paper published in Nature Geoscience, the team describes how they studied data from satellites and ocean surface sensors to measure changes in ocean mass and density which allowed them to calculate an average global sea level rise of nearly 2.4mm/year.

The researchers note that sea level changes come about in three main ways: changes in the mass of the water in the ocean, its density, and changes in the volume of . To measure all of these over the period 2005 to 2011, the team studied data from the Gravity Recovery and Climate Experiment (GRACE) and from the Argo project (a global array of 3,500 profiling floats that record ocean temperatures and salinity on an ongoing basis.)

from GRACE allows researchers to measure the mass of the world's oceans (divided into six regions) and thus the changes that occur over time. The data showed, the researchers report, a global increase in ocean mass that led to an average ocean level rise of 1.8mm/year during the years studied. They suggest the increase in mass was due to melting of the and glaciers atop mountains around the globe.

In studying data from Argo, the researchers found a reduction in the average density of the world's oceans led to a rise in sea levels of approximately 0.6mm/year. The researchers did not delve into the nature of the decrease in sea water density, but the presumption is that it's due to an increase in .

To calculate the total average over the years studied, the researchers added the rise due to an increase in ocean mass and the rise due to a reduction in average density—this gave them an average rise of 2.39mm/year. The researchers note their numbers reflect more rise than other studies have found but agree with those that have claimed sea levels are rising at an accelerated rate in more recent years. They also conclude that most of the change in global sea levels is due to melting of polar ice sheets and mountain glaciers.

Explore further: Questions of continental crust

More information: Contribution of ice sheet and mountain glacier melt to recent sea level rise, Nature Geoscience (2013) doi:10.1038/ngeo1829

Abstract
Changes in global mean sea level primarily reflect the sum of three contributions: water mass changes in the oceans, water density changes, and variations in the volume of the ocean basins. Satellite altimetry data1, 2, 3, 4 suggest that sea level rose by about 2.39±0.48 mm yr−1 between 2005 and 2011. However, previous estimates5, 6, 7, 8, 9 of sea level rise from density and ocean mass changes were lower than the altimeter data indicate. Here we show that the gap in the sea level budget disappears when we combine gravity data from the GRACE (Gravity Recovery and Climate Experiment) satellite mission and temperature and salinity observations from the Argo programme collected between 2005 and 2011. The Argo data indicate a density-driven sea level rise of 0.60±0.27 mm yr−1 throughout this period. To estimate ocean mass change from the gravity data, we developed a forward modelling technique that reduces the bleeding of terrestrial signals into the ocean data. Our reassessment suggests an ocean mass contribution of 1.80±0.47 mm yr−1, for a total sea level rise of 2.40±0.54 mm yr−1, in agreement with the altimeter-based estimates. On the basis of the GRACE data, we conclude that most of the change in ocean mass is caused by the melting of polar ice sheets and mountain glaciers. This contribution of ice melt is larger than previous estimates10, but agrees with reports11, 12, 13 of accelerated ice melt in recent years.

Related Stories

Models without volcanic forcing underestimate sea level rise

May 28, 2013

Volcanic eruptions spew sulfur dioxide into the atmosphere, which tends to block incoming sunlight, sometimes cooling the planet for several years. This cooling leads to a decrease in the heat stored in the ocean and thus ...

La Nina caused global sea level drop

Oct 29, 2012

The 2011 La Niña was so strong that it caused global mean sea level to drop by 5 millimeters (0.2 inches), a new study shows. Since the early 1990s, sea level has been rising by about 3 millimeters (0.1 inches) per year, ...

Recommended for you

Questions of continental crust

9 hours ago

Geological processes shape the planet Earth and are in many ways essential to our planet's habitability for life. One important geological process is plate tectonics – the drifting, colliding and general ...

Better forecasts for sea ice under climate change

Nov 25, 2014

University of Adelaide-led research will help pinpoint the impact of waves on sea ice, which is vulnerable to climate change, particularly in the Arctic where it is rapidly retreating.

User comments : 10

Adjust slider to filter visible comments by rank

Display comments: newest first

VENDItardE
1.3 / 5 (13) Jun 03, 2013
Rigggghhhhhhht.
Howhot
3.8 / 5 (10) Jun 03, 2013
On the basis of the GRACE data, we conclude that most of the change in ocean mass is caused by the melting of polar ice sheets and mountain glaciers. This contribution of ice melt is larger than previous estimates10, but agrees with reports11, 12, 13 of accelerated ice melt in recent years.


Yep, that sounds about right. I've always been a fan of 12 and the accelerated ice melt theory.
ScooterG
2 / 5 (12) Jun 07, 2013
2.4mm is 3/32 of an inch.

I call bulls**t on this one.

I do not believe it is physically or humanly possible to measure the ocean levels accurately enough to make this claim. Nice try, but a swing-anda-miss.
Howhot
3.7 / 5 (9) Jun 07, 2013
Scooter, your always calling bulls**t on something. This is from high precision satellite data and matched to temperature and salinity observations. What do you need? To be spoon-fed the data like your nanny did? So in 10 years its 2.4cm=1in. and 100 year 24cm=10in without tides. Based on the impact that sea-level rise has had on some island in the period 2005-2011, this will really cause some concern for some nations.
ScooterG
2.1 / 5 (11) Jun 08, 2013
Scooter, your always calling bulls**t on something. This is from high precision satellite data and matched to temperature and salinity observations. What do you need? To be spoon-fed the data like your nanny did? So in 10 years its 2.4cm=1in. and 100 year 24cm=10in without tides. Based on the impact that sea-level rise has had on some island in the period 2005-2011, this will really cause some concern for some nations.


Did they account for any seismic and volcanic activity or anything else that might displace water? How do you measure that when you don't even know it's happening?

We will never have all the information we need to make such a claim - I don't care if you have 50,000 satellites up there and 2,000,000 sensors down here, it's up-proveable bullsh*t.
ubavontuba
1.4 / 5 (9) Jun 08, 2013
More bad science from GRACE. GRACE cannot differentiate the mass of the oceans from the mass of the crust, the mantle, and whatever lies between it and the center of the earth. How do they know that denser magma hasn't simply circulated around?

Yep, that sounds about right. I've always been a fan of 12 and the accelerated ice melt theory.
Logical fallacy. If glacial ice melt was accelerating, then sea level should be changing at a correspondingly accelerating rate. As this isn't happening, one can conclude that ice melt is therefore not accelerating.

But AGWites aren't known for their logic and science skills. To them it's all about the doomsday march.

Anyway, when the beaches I played on as a kid begin to diminish, I'll begin to worry. Otherwise it's all B.S..

ScooterG
1 / 5 (7) Jun 08, 2013
Scooter, your always calling bulls**t on something. This is from high precision satellite data and matched to temperature and salinity observations. What do you need? To be spoon-fed the data like your nanny did? So in 10 years its 2.4cm=1in. and 100 year 24cm=10in without tides. Based on the impact that sea-level rise has had on some island in the period 2005-2011, this will really cause some concern for some nations.


Did they account for any seismic and volcanic activity or anything else that might displace water? How do you measure that when you don't even know it's happening?

We will never have all the information we need to make such a claim - I don't care if you have 50,000 satellites up there and 2,000,000 sensors down here, it's up-proveable bullsh*t.


Sorry for the typo...that should read "un-proveable".
Neinsense99
3.4 / 5 (10) Jun 08, 2013
VENDItardE:

Rigggghhhhhhht.

Wwiiinnnnggg....
Neinsense99
3.4 / 5 (10) Jun 08, 2013
Scooter, your always calling bulls**t on something. This is from high precision satellite data and matched to temperature and salinity observations. What do you need? To be spoon-fed the data like your nanny did? So in 10 years its 2.4cm=1in. and 100 year 24cm=10in without tides. Based on the impact that sea-level rise has had on some island in the period 2005-2011, this will really cause some concern for some nations.


Did they account for any seismic and volcanic activity or anything else that might displace water? How do you measure that when you don't even know it's happening?

We will never have all the information we need to make such a claim - I don't care if you have 50,000 satellites up there and 2,000,000 sensors down here, it's up-proveable bullsh*t.

Argument from ignorance.
ScooterG
1.5 / 5 (8) Jun 09, 2013
Scooter, your always calling bulls**t on something. This is from high precision satellite data and matched to temperature and salinity observations. What do you need? To be spoon-fed the data like your nanny did? So in 10 years its 2.4cm=1in. and 100 year 24cm=10in without tides. Based on the impact that sea-level rise has had on some island in the period 2005-2011, this will really cause some concern for some nations.


Did they account for any seismic and volcanic activity or anything else that might displace water? How do you measure that when you don't even know it's happening?

We will never have all the information we need to make such a claim - I don't care if you have 50,000 satellites up there and 2,000,000 sensors down here, it's up-proveable bullsh*t.

Argument from ignorance.


100,000,000 square miles of ocean up to 36,000 feet deep??? Ain't a snow-ball's chance in Hell of accurately knowing the volume of a tub like that.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.