Thursday, July 17, 2014

Paper predicts increased precipitation in Antarctica will slow sea level rise by > 1 mm/yr

Comment by Frank Walters, elevated to a post:

I found an interesting paper: Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues, by C. GENTHON, G. KRINNER, H. CASTEBRUNET (Annals of Glaciology 50 2009)

The paper suggests that the INCREASE in snow and ice on the margins of Antarctica may cause the rate of rise in global sea level to be 1 mm per year LESS than the rate of rise otherwise expected..

The increase in sea ice can be linked to increase in precipitation on the margins of Antarctica. This is what one would expect intuitively, since the melting of the grounded coastal ice in accompanied by an endothermic process that causes refreezing as sea ice.

A buildup of snow on top of the glacier adds weight and causes strain within the ice (shear) and thus increases the amount of ice moving down slope and calving from the seaward margin of the grounded ice.

What needs to be explained is the increase in precipitation over the margins of Antarctica.

Since the interior of the continent is a desert, snowfall on the plateau can be ignored.

Full paper available here:

Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues


ABSTRACT. All climate models participating in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, as made available by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) as the Coupled Model Intercomparison Project 3 (CMIP3) archive, predict a significant surface warming of Antarctica by the end of the 21st century under a moderate (SRESA1B) greenhouse-gas scenario. All models but one predict a concurrent precipitation increase but with a large scatter of results. The models with finer horizontal resolution tend to predict a larger precipitation increase. Because modeled Antarctic surface mass balance is known to be sensitive to horizontal resolution, extrapolating predictions from the different models with respect to model resolution may provide simple yet better multi-model estimates of Antarctic precipitation change than mere averaging or even more complex approaches. Using such extrapolation, a conservative estimate of the predicted precipitation increase at the end of the 21st century is +30 kg m–2 a–1 on the grounded ice sheet, corresponding to a > 1mm a–1 sea-level rise [i.e. equivalent to 1 mm less sea level rise & acting as a negative feedback]. About three-quarters of this rise originates from the marginal regions of the Antarctic ice sheet with surface elevation below 2250 m. This is where field programs are most urgently needed to better understand and monitor accumulation at the surface of Antarctica, and to improve and verify prediction models.


  1. Earth is an 8,000 mile globe with a surface area of 210 million square miles. 71% of it is covered by water with an average depth of 16,000 feet or 3.03 miles, thus includes 451 million cubic miles of sea water. Every foot of depth is equal to 28,000 cubic miles of seawater.

    Arctic ocean ice floats and is accounted for like ice cubes in a glass of water. Melting it makes no difference in the sea level. According to The Journal of Geophysical Research, JGR, all the glaciers and Antarctica include 41,000 cubic miles of ice which melt forming 36,900 cubic miles of water. This would increase the water level on Earth 1.32 feet or 16 inches and not the 260 feet claimed by the USGS bureau.

    The published JGR analysis is never reported in mainstream media. People who want to scare you say the seas will rise 260 ft. They want new taxes, your money and more power by scaring you. It is just that simple.

    For science and political matters explained to you in language you can understand come to "Two Minute Conservative," via Google and when you speak they will listen.

    1. Adrian,

      The JGR paper finds all the glaciers EXCLUDING Antarctica and Greenland contain 41,000 cubic miles of ice.

      Please repeat your calculations...


    3. That link supports my figure. I have done this from data that included all the ice on Antarctica, I am sure as "all the glaciers" would include the ice on Antarctica.

    4. The piece was written in a confusing manner regarding studies of the many small glaciers, but then totaled the figure stating, "Through a combination of direct satellite observations and modeling, they determined the total volume of ice tied up in the glaciers is nearly 41,000 cubic miles (170,000 cubic kilometers), plus or minus 5,000 cubic miles (21,000 cubic km)."

    5. The paper is here and it clearly says "For all mountain glaciers and ice caps outside of the Antarctic and Greenland ice sheets we find a total ice volume of 170 × 103 ± 21 × 103 km3, or 0.43 ± 0.06 m of potential sea level rise."