Public Release: 19-Nov-2018
The research is the first to show how the melting of the Antarctic ice sheet will affect future climate
University of Arizona
As the Antarctic ice sheet melts, warming of the atmosphere will be delayed by about a decade but sea level rise will accelerate, according to new research scheduled for advance online publication in the journal Nature.
The study is the first to project how the melting of the Antarctic ice sheet will affect future climate, said first author Ben Bronselaer of the University of Arizona, adding that current climate models do not include the effects of melting ice on the global climate.
The entire Earth will continue to warm, but the atmosphere will warm more slowly because more of the heat will be trapped in the ocean, he said
“Warming won’t be as bad as fast as we thought, but sea level rise will be worse,” said Bronselaer, a postdoctoral research associate in the UA Department of Geosciences.
Observations show that the Antarctic ice sheet has been melting faster in recent years.
The UA-led team found that by the year 2100, sea level could rise as much as 10 inches more than the previous estimate of approximately 30 inches by 2100.
“No one had looked at the big picture of what Antarctic ice sheet melting means for the global climate,” he said.
To figure out whether the melting of the Antarctic ice sheet would affect global climate, the research team modified one of the most current climate computer models to include the ice melt.
Adding the melted ice into the team’s model indicated that the global temperature would increase by 2 degrees C (3.6 F) by the year 2065, rather than the year 2053, the team writes.
In addition to slowing warming and increasing sea level, the melting of the Antarctic ice sheet will change precipitation regimes because the tropical rain belt will shift north, said senior author Joellen Russell, who holds the Thomas R. Brown Distinguished Chair of Integrative Science and is an associate professor of geosciences at the UA.
“Our projections indicate the tropical rain belt will shift toward the Northern Hemisphere, making it slightly wetter in the Northern Hemisphere and slightly drier in the Southern Hemisphere than previously predicted,” Russell said.
The team’s research paper, “Change in future climate due to Antarctic meltwater,” is scheduled for online publication in the journal Nature on Nov. 19. A complete list of coauthors and their affiliations is at the end of this release.
The research is part of the National Science Foundation-funded Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) Project. The National Oceanic and Atmospheric Administration and NASA also funded the research.
Russell leads the part of SOCCOM that is charged with improving how the Southern Ocean is represented in the computer models of global climate. The Southern Ocean is the ocean that surrounds Antarctica.
Researchers previously thought the melting of the Antarctic ice sheet would affect only sea level, not the entire climate system.
To test that idea, Bronselaer ran a climate model with and without the ice- sheet melting included. The team included researchers from NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey and from Princeton University. The scientists used NOAA GFDL’s climate model called ESM2M and tested the simulation over the time period from 1950 to 2100.
In addition, they set the level of greenhouse gas emissions for the 21st century using the scenario known as RCP8.5, sometimes called the “business-as-usual” scenario.
Russell and Bronselaer were both surprised by their findings. They did not expect the Antarctic meltwater to affect the global climate system.
Ocean circulation moves heat from the equator to the poles. The heat is then released into the atmosphere, Russell said. However, the team’s new research reveals that the additional freshwater from the melting ice sheet acts like a lid on the waters around Antarctica and slows the release of heat.
“It’s the first new identified feedback on climate in 20 years,” she said. “The melting delays warming – it’s still warming but it will warm less steeply and give us another 15-year grace period.”
Another SOCCOM team that has deployed robotic floats throughout the Southern Ocean that are gathering temperature, salinity, and biological and chemical information about the ocean.
Russell said her next steps are evaluating climate models against the observations from the SOCCOM floats to see what else the models might be missing.
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Bronselaer and Russell’s coauthors on the paper, “Change in future climate due to Antarctic Meltwater,” are Michael Winton of the NOAA GFDL in Princeton, New Jersey; Stephen M. Griffies of NOAA GFDL and Princeton University; William J. Hurlin of NOAA GFDL; Keith B. Rodgers of Princeton University; Olga V. Sergienko of NOAA GFDL and Princeton University; and Ronald J. Stouffer of the University of Arizona and NOAA GFDL.
This is a typical “What if”scenaro beloved by the Warmers. But then the Media comes along and think that such “Results”is real scientific data and publishes it.
Is ther e a “Honest”University or research centtre anywhere in the World which has a “Model”which says that the World is cooling down ?
MJE
>..Russia…
This is a typical “What if”scenaro beloved by the Warmers. But then the Media comes along and think that such “Results”is real scientific data and publishes it.
Is ther e a “Honest”University or research body anywhere in the World which has a “Model”which says that the World is cooling down ?
MJE
The following, all of which directly affect global sea-level, have very high uncertainties on their associated quantitative values in the past, today and going into the future:
1) the temperature and associated heat distribution throughout Earth’s oceans as a function of depth, particularly below 2000 m (the average depth of Earth’s oceans is about 3,700 m).
2) the overall rate at which heat energy is transferred vertically from Earth’s ocean surface layer to its depths
3) the overall rate at which heat energy is transferred horizontally across Earth’s oceans, especially from equator to polar regions
4) the overall rate at which heat energy is removed from the oceans due to evaporation (= function of water temperature, air temperature, relative humidity, wind speed, sea state and surface contamination)
Better accuracy (via physical measurements) of all of the above items is needed to accurately calculate the degree to which sea-level rise can be explained solely by temperature-induced volumetric expansion of seawater at global scale. If this were to be done, I am confident that melting of ice that is resting on land will be found to be a relatively minor contributor to sea-level rise.
Notwithstanding the above, there have been no accurate measurements, on a global scale, of the extent to which land subsidence and land uplift (plate tectonics and isostatic rebound from Earth’s last glacial period) in ocean bottom contours have combined to contribute to global sea-level rise.
Given this situation, one is hard pressed to imagine there is any accuracy in assigning a quantitative value to the extent melting ice in Antarctica (or elsewhere on Earth) affects sea-level rise.
In addition, the basic laws of physics say that since the world’s oceans are in thermal contact with solid Earth and its gaseous atmosphere, there can be no such thing as “trapping heat” in the ocean (water).
“Ocean circulation moves heat from the equator to the poles. The heat is then released into the atmosphere, Russell said” – this explains why the air temperatures in the Polar regions are so warm! I am off there for my next beach holiday.
What Russel should have said, is, that the heat remaining in the oceanic water after it’s long journey from the Tropics, has been dispersed into an exponentially larger volume of water, which warms the Polar regions very slightly.
Calling this garbage research and the dudes ho publish scientists is a category error.
What they did is not research. Scientific research is determining facts. And these clons ar not “scientists”
They are computer gamers running Madden 2018 and telling us ho ill in the super bowl in 2020.
Agreed alter, but check your keyboard – lol. In particular the “” key, I mean the “” key! Damn – the one beteen “q” and “e”… ;P
But we are doomed anyway.
Although currently at Arizona, (they move around like this to keep up the consensus coming out of the multifarious climate institutes, he is a product of Oxford Climate Change Institute, (Myles Allen, Diana Liverman, also at Arizona, Martin Parry)
https://bronselaer.files.wordpress.com/2015/11/cv_benbronselaer2.pdf
Yet another study making a prediction. Tested by running “a climate model with and without the ice- sheet melting included.” I’m sorry but real science demands that your hypothesis and prediction be validated with actual observations and measurements. Models are nothing more than part of the hypothesis.
Jim Whelan
You said, “Models are nothing more than part of the hypothesis.”
Models are complex hypotheses of how a dynamic system (such as climate) works. Unfortunately, they are not subject to rigorous testing against real world data to verify that they provide results that are sufficiently accurate to have predictive value. Modelers should set a goal, such as a 10% acceptance range, and evaluate both false-positive and false-negatives for temperature, precipitation, and wind. They should be rejected if any of the three predictions exceed the tolerance.
Instead, we have a situation where Hansen’s 1988 prediction is lauded as being “highly accurate” when it was only shear luck that the intermediate scenario came close to reality (and not as close as a naive linear extrapolation) ONLY because Hansen assumed a volcanic eruption that never happened. Being right for the wrong reason is unacceptable in science.
The biggest problem with all these projections is the issue of coastal area.
Coastal area is affected by sea level but many things affect the height of the land and the amount of coastal area.
Over the last 30 years according to a comprehensive study done 5 years ago the total coastal area of the world has been climbing. 30,000 km increased coastal land size. In other words even with all the sea level rise the amount of land we are living on is climbing NOT decreasing. Many people may find this hard to believe but it is true. There are many reasons for land and coastal areas to increase.
1. Silt from mountain erosion spreads down and accumulates at the sea.
2. Volcanic eruptions
3. Dendritis from the ocean accumulates on beaches
4. Increased rainfall is filling acquifers and increasing height of land 0.3mm yearly.
5. Natural tectonic plate movements
6. a natural rebound effect as glaciers melt and mountans erode of less mass causes the land in general to float higher just like the land was like sea ice. Archimedes principle on a larger scale
7. Some of the projected sea level rise is faked and imputed by removing the rebound from the ice age which is happening but which they subtract anyway from their estimates.
8. The biggest reason is: Man builds coastline. We build, fill in and expand coastline constantly all over the world.
The net result of these 8 things is that it has completely mitigated all sea level rise for decades. It will probably do so for the foreseeable future so essentially this entire worry is vastly misplaced and misunderstood.
With 40 years development
“current climate models do not include the effects of melting ice on the global climate.”
said Bronselaer,
“No one had looked at the big picture of what Antarctic ice sheet melting means for the global climate,” he said.
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Little late to search where to begin with.